Abstract. In the indirect dark matter (DM) detection framework, DM particles would produce some signals by self-annihilating and creating standard model products such as γ rays, which may be detected by ground- and space-based telescopes. Dwarf galaxies represent promising targets for the DM search as they are believed to be DM dominated and possess a reduced astrophysical background. The H.E.S.S. telescopes observed three different kinds of these objects known as dwarf irregular, dwarf spheroidal, and dwarf ultrafaint galaxies. We search for a DM signal looking for excess of γ rays towards these dwarf galaxies. We present the results on these observations interpreted in terms of velocity-weighted cross section for DM self-annihilation hσvi as a function of DM particle mχ mass for several annihilation channels. Another source we study is the nearest galaxy, Andromeda galaxy (M31). This source contains a non negligible astrophysical component that we need to characterize before studying a potential DM signal. We present the ongoing work on M31 morphology using the γ-ray data of Fermi-LAT. The results are obtained with skyFACT, a new method of γ-ray fitting which combines template fitting and image reconstruction. Thursday, 14 Novembre 2019 at 14:00

Fei Xie
INAF - Istituto di Astrofisica e Planetologia Spaziali, Roma

The Imaging X-ray Polarimetry Explorer (IXPE)

Abstract. The next NASA Small Explorer (SMEX) mission, IXPE ( Imaging X-ray Polarimetry Explorer) , will be launched in 2021, with three identical X-ray mirror module assemblies and Gas Pixel Detectors (GPD). IXPE introduces the capability for X-ray polarimetric imaging, uniquely enabling the measurement of X-ray polarisation with scientifically meaningful spatial, spectral, and temporal resolution. During its baseline two-year operation, IXPE will have polarisation measurements on a few dozen sources, including various types of neutron stars, blackhole systems, active galactic nuclei, and supernova remnants, help to probe the origin and destiny of our universe. A series of simulation activities together with the calibration for flight units are in progress. The polarimeter design and expected performance will be discussed. Wednesday, 19 June 2019 at 14:00

Tomaso Belloni
INAF - Osservatorio Astronomico di Brera

Fast variability in black-hole binaries: accretion and General Relativity

Abstract. I will review the current standpoint of fast variability from black-hole binary systems. The large amount of data obtained in the past two decades has led to a significant advancement in our knowledge, although it still needs to be consolidated through new observations. I will present the more recent evidences of General Relativistic effects obtained from the data from NASA’s RossiXTE mission and will present new data from NICER (NASA) and Astrosat (India). Monday, 8 April 2019 at 14:00

Luciano Burderi
University of Cagliari

THE HERMES PROJECT (HIGH ENERGY RAPID MODULAR ENSEMBLE OF SATELLITES): PROBING SPACE-TIME QUANTUM FOAM AND HUNTING FOR GRAVITATIONAL WAVE ELECTROMAGNETIC COUNTERPART

Abstract. I discuss how several of the proposed models for space-time quantization predict an energy dependent speed for photons. Although the predicted discrepancies with the general speed of light are minuscule, I discuss how it is possible to detect this intriguing signature of space-time granularity with a new concept of modular observatory for photons in the energy band 10 keV 30 MeV. This observatory may consist of a swarm of micro/nano- satellites on low orbits. Sub-microsecond time resolution and wide energy band allows to probe tiny energy dependent delays, expected to be the signature of the granular structure of space- time in several of the proposed theories of Quantum Gravity. Moreover this kind of experiment allows to perform temporal triangulation of high signal to noise impulsive events with positional accuracies of few arcseconds, making an observatory like that a promising hunter for the elusive electromagnetic counterparts of Gravitational Waves.

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Manisha Caleb
University of Manchester

The fast radio burst phenomenon

Abstract. Radio astronomy is currently exploring an intriguing new phase space that probes the dynamic Universe on timescales of milliseconds. Recent development of sensitive, high time resolution instruments over the last decade has enabled the discovery of millisecond duration fast radio bursts (FRBs). The FRB class encompasses a number of single pulses, each unique in its own way, hindering a consensus for their origin. The key to demystifying FRBs lies in discovering many of them in realtime in order to identity commonalities. Despite rigorous follow-up of the ~80 published FRBs only two have been seen to repeat suggesting the possibility of there being two independent classes. In my talk I will discuss the recent developments in the field, some of the open questions in FRB astronomy and how the next generation telescopes are vital in the quest to understand this enigmatic population.

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Lionel Metrailler
Suisse Space Center, EPFL

Phenomenological Earth Radiation Belts Modelling

Abstract. Since the Van Allen Belts are highly dynamic, this 3D model needs to include time variations linked to thesunactivity and position with respect to the Earth magnetosphere. An insight on this variations applied to the 3D model will also be shown.

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Saverio Braccini
Albert Einstein Center for Fundamental Physics, Laboratory for High Energy Physics, University of Bern

The Bern medical cyclotron laboratory and its beam line for multi-disciplinary research

Abstract. The Bern medical cyclotron laboratory is based on a 18 MeV proton cyclotron equipped with a specifically conceived 6 m long research beam line, terminated in a separate bunker. This particular configuration is designed for industrial Positron Emission Tomography (PET) radioisotope production as well as for novel detector, radiation biophysics, radiation protection, materials science, radiochemistry and radiopharmacy scientific activities. In particular, radiation hardness studies for space missions and high- energy physics experiments are performed. This project is the result of the successful collaboration among the University Hospital in Bern (Inselspital), the University of Bern and industrial partners. This facility is open to national and international collaborations. The scientific results of the first five years of operation will be presented.

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Mike Eracleous
Pennstate

Three LINERs Under the Hubble Space Microscope

Abstract. Low-Ionization Nuclear Emission Regions (LINERs) are found in approximately half of nearby galaxies. Their defining characteristic are strong, forbidden emission lines from ions in low-ionization states, e.g., [O I], [O II], [N II], [S II], that are emitted from a region of a few hundred parsec in size at the center of the galaxy. The vast majority of LINER nuclei harbor accreting, supermassive black holes, which suggests that photoionization by radiation from the accretion flow may be responsible for the relative intensities of the emission lines of LINERs. But other models invoking shocks or hot stars can also explain many aspects of the observed spectra. Moreover the active nuclei in LINERs do not emit enough ionizing photons to reproduce the absolute strengths of the emission lines from the line-emitting gas. In this talk, I will begin with a historical introduction to LINERs and then go on describe the puzzles and open questions. In the last part of the talk I will describe spatially-resolved spectroscopic observations of three LINERs that our team carried out recently with the Hubble Space Telescope. We achieved a spatial resolution of better than 10 pc, effectively placing the galactic nuclei under the microscope and looking for the source of power responsible for the emission lines on a variety of scales from a few pc to 100 pc. Based on a detailed comparison of observed emission-line strengths to model predictions, we found that photoionization from the active nucleus indeed powers the line emission in the inner 20-50 pc. At larger distances from the nucleus shocks appear to be responsible for exciting the gas. The shocks in this small sample of galaxies are likely a result of the interaction of jets with circumnuclear gas. Thus, the characteristic LINER spectrum represents a combination of multiple excitation mechanisms.

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Sotiria Fotopoulou
Department of Physics, Durham University

The XXL large scale structure: exploring the impact on AGN evolution

Abstract. In this talk I will give an update on the largest XMM-Newton survey to data, the XXL Survey. Spanning a combined 50 sq. deg. area, the XXL has revealed more that 400 X-ray detected clusters and more than 25 000 AGN. Due to it's contiguous area and medium depth, we are able to explore for the first time the cluster and field population of AGN from a single survey. I will show preliminary results of the impact of the large scale structure on AGN evolution and discuss future opportunities.

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Hiromitsu Takahashi
Hiroshima University

Hard X-ray polarization observations of Crab and Cygnus X-1 by PoGO+

Abstract. PoGO+ is a balloon-borne hard X-ray Compton polarimetry telescope operating in the energy range of 20–180 keV. The instrument is optimized for point-sources and has a field of view collimated to 2∘. During 1-week flight in 2016 from Kiruna, Sweden to Victoria island, Canada, PoGO+ managed to observe Crab and Cygnus X-1. The polarization fractions are measured as (20.9+-5.0)% for Crab, and the 90% upper limit of <8.6% for Cygnus X-1. I will introduce the PoGO+ detector performance and explain the polarization results.

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Ms. Pragati Pradhan
Pennsylvania State University USA and St. Joseph's College, Darjeeling India

Exploring the possibility of on-board transient detection with Athena/WFI

Abstract. X-ray transients are among the most enigmatic objects in the cosmic sky. The unpredictability of their transient behaviour has been a study of much interest in the recent years. While significant progress has been made in this direction, a more complete understanding of such events is often hampered by the delay in the rapid follow-up of any transient event. An efficient way to mitigate this constraint would be to devise a way for on-board detection of such transient phenomenon. The Wide Field Imager (WFI), which is a part of the upcoming X-ray mission Athena, with its 40’ X 40’ field of view can add some valuable contribution to this. In this work, we discuss an algorithm for the on-board detection of X-ray transients with WFI. We will also present a few test cases for the feasibility test of that algorithm on Swift-XRT data. Finally, we discuss what type of X-ray transients are best suited for on-board detection from WFI, their probability of detections and the useful science that can follow.

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Leanne Guy
LSST

LSST: Overview and status update

Abstract. ion on Cerro Pachón in Chile, will conduct an unprecedented decade-long survey \ of the southern sky. Featuring an 8.4 m (6.5 m effective) primary mirror, a 9.6\ deg2 field of view, a 3.2 Gigapixel camera and an automated data processing sy\ stem, LSST seeks to enable science in four main areas: the nature of Dark Matte\ r and understanding Dark Energy, cataloging the Solar System, exploring the cha\ nging sky, and Milky Way structure and formation. In this talk I will provide \ and overview and status update of the project.

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Denis Bernard
Laboratoire Leprince-Ringuet ECOLE POLYTECHNIQUE Route de Saclay 91128 PALAISEAU CEDEX

High-performance gamma-ray astronomy and polarimetry with gamma -> e+e-

Abstract. High-sensitivity observations of cosmic sources are scarce in the gap that lies between the domains in which Compton telescopes and pair telescopes are at their best, i.e. in the energy range ~ 0.1 -- 100 MeV. Also gamma-ray polarimetry, which would be such a powerful diagnostic of the process(es) at work in gamma-ray emitters, in particular related to the intensity and to the homogeneity/turbulence of the magnetic field, has never been achieved with e+e- pairs on cosmic sources. I will present how low-density active targets such as gas detectors can improve on the observation of MeV photons and enable (linear) polarimetry. We have characterized a gas time-projection chamber (TPC) prototype on beam and demonstrated for the first time the polarimetry of a MeV gamma-ray beam with a good dilution factor [Astroparticle Physics 97 (2018) 10].

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Aru Beri
University of Southampton

Pulse Profiles: A unique tool to probe into the accretion geometry of Accretion Powered X-ray pulsars

Abstract. In the case of high magnetic field neutron star binary systems (B ~ 1012 -1013 Gauss), the magnetic field plays an important role in channeling matter onto its surface. One important manifestation of the interaction between the neutron star accretion disc and its magnetic field is the accretion torque, which can result in transitions between spin-up and spin-down of the star. In this talk, I will discuss the process of accretion onto high B-field neutron stars: the accretion stream structure and formation, shape of the pulse profile and its changes with accretion torque. In particular, I will discuss the results from our recent study of a unique X-ray pulsar, 4U 1626-67. I will also present some results of Swift J0243.6+6124 obtained using 50,000 sec observation made by the Large Area X-ray Proportional Counter (LAXPC) onboard AstroSat. Swift J0243.6+6124 is a newly discovered X-ray pulsar, with a spin period of 9.85 sec. This source went into outburst in October 2017 and is of particular interest because it exhibited a super-Eddington X-ray luminosity (Lx∼5x1038 erg/sec, assuming a source distance of 4 kpc) within a month of outburst onset. In contrast to what is seen in other similar sources (like 4U 0115+63), a radio jet was also observed at peak Lx.

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David Smith
CENBG Bordeaux

Gamma Phase-folding a Thousand Pulsars

Abstract. In its 10th year on orbit, the Fermi LAT continues to discover GeV gamma-rays from over 20 pulsars per year. The most sensitive way to find them is to use rotation ephemerides to "phase fold" the gamma photons, to then look whether the resulting phase histogram is flat or not. We are currently doing this for over a thousand radio pulsars, using ephemerides provided by the Parkes, Jodrell Bank, and Nancay radio telescopes. I will present a dozen gamma-ray pulsars found in 2017, and explain how they enhance the sample of over 200 pulsars we already had. I will discuss possible causes of the gamma-ray "deathline" near a spindown power of Edot ~ few 1E33 erg/s. Finally, I will say some words about extrapolating the observed gamma-ray pulsar population to estimate the contribution of unresolved pulsars to the diffuse background.

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Chin-Ping Hu
University of Honk Kong, Hong Kong Special Administrative Region of the People's Republic of China

Magnetars and Rotation Powered Pulsars

Abstract. Pulsars are fast-rotating neutron stars with strong magnetic fields. Magnetars are pulsars with extraordinarily strong magnetic fields and remarkable for the bursting activities and high X-ray luminosities. However, recent discoveries blurred the boundary between magnetars and rotation-powered pulsars (RPPs). In this talk, I will introduce the recent works on the high-magnetic-field RPPs, especially the youngest ones of J1846-0258, J1119-6127, and B1509-58. Young and high-magnetic-field RPPs have surface temperatures between the magnetars and canonical RPPs, indicating that high-magnetic-field RPPs are potential bursters and may contain toroidal magnetic fields according to the magneto-thermal evolution model. This model implies that the toroidal field could play an important role in bursting rate and break the surface temperature symmetry. Our recent work suggested that the distribution of magnetar's pulse profile cannot be explained by a symmetric surface temperature distribution with an arbitrary viewing angle. This result agreed with the implication of the magneto-thermal evolution.

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Neven Caplar
ETH Zurich, Switzerland

Quasar variability of AGN in Palomar Transient Survey

Abstract.

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Matteo Bachetti
INAF-Osservatorio Astronomico di Cagliari, Italy

Mighty mice in the cosmos - Ultraluminous X-ray sources

Abstract. The extreme emission of Ultraluminous X-ray Sources (ULX) represents a unique testing environment for compact objects population studies and the accretion process. Their nature has long been disputed. Their luminosity, well above the Eddington luminosity for a stellar-mass black hole, was often considered evidence for intermediate-mass black holes, or a signature of a poorly known regime of super-Eddington accretion. Both these interpretations are important to better understand the accretion process and the evolution of massive black holes. The last few years have seen a dramatic improvement of our knowledge of these sources. In particular, the super-Eddington interpretation for the bulk of the ULX population has gained a strong consensus, even more after the discovery of three neutron star-powered ULXs (the "mighty mice"), at 100-1000 times their Eddington luminosity.

I will review the progress done in the last few years on these exciting sources, and I will devote the second half to explaining some current efforts in the identification of their compact objects with a multi-wavelength study of variability.

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Stephan Zimmer
University of Geneva

Fermi's view on Galaxy Clusters: 7+ years of observations but no detection yet

Abstract. Galaxy clusters are the most massive virialized systems known in the Universe and are believed to have formed through large scale structure formation. They host relativistic cosmic-ray (CR) populations and are gravitationally bound by large amounts of Dark Matter (DM), both providing conditions in which high-energy gamma rays may be produced either via CR interactions with the intracluster medium or through the annihilation or decay of DM particles. Prior to the launch of the Fermi satellite, predictions were optimistic that these sources would be established as gamma-ray-bright objects by observations through its prime instrument, the Large Area Telescope (LAT). Yet, despite numerous efforts, even a single firm cluster detection is still pending, requiring us to re-evaluate the underlying physics processes. In my talk I will provide an overview and discuss recent studies carried out by the LAT collaboration aiming to discover these missing gamma rays and discuss detection prospects with respect to an extended Fermi LAT mission.

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Christian Bockermann & Kai Brugge
TU Dortmund, Germany

Machine Learning for Gamma/Hadron Separation in FACT

Abstract.

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Miriam Ramos Ceja
Argelander-Institut für Astronomie, University of Bonn

Modeling the gas content in groups and clusters from the Sunyaev-Zel'dovich effect angular power spectrum

Abstract. The angular power spectrum of the thermal Sunyaev-Zel'dovich (tSZ) effect is considered an effective tool for constraining cosmology due to its sensitivity on key cosmological parameters like the normalization of the matter power spectrum. Conversely, if the relevant cosmological parameters are known from other probes, the tSZ power can be used as a powerful probe to investigate the gas distribution inside galaxy groups and clusters out to the redshift of their formation. In our work we explore the latter path to set meaningful constraints on the extent of non self-similar evolution in the cluster gas distribution using GNFW pressure models. The tSZ power takes its contribution from groups and clusters of all masses in the universe, and has particularly strong dependence on the high-z, low mass systems which are difficult to probe directly. Using SPT measured values of the CMB bandpowers we model the impact of non-standard scenarios like a redshift dependent gas-mass fraction or a changing ratio of cool core to non-cool core clusters on the tSZ power. We construct X-ray scaling relations from our results and compare them with recent publications to highlight some possible selection effects in the X-ray. Finally, we use simulated bandpowers for a future SZ experiment on-board CCAT to show how its improved sensitivity and angular resolution can break parameter degeneracies to simultaneously constrain the shape and evolution of the gas distribution with high accuracy.

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Odele Straub
Observatoire de Paris, France

Accretion discs around black holes. A journey.

Abstract.

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Andres Carmona
Institute of Planetology and Astrophysics of Grenoble, France

Determining the gas and dust structure of the gapped protoplanetary disk HD 135344B (SAO 206462)

Abstract. Transition disks are protoplanetary disks with an inner dust gap. The origin of these cavities is currently under debate. One exciting possibility is that they might be related to planet formation. HD 135344B is a F4V star with a transition disk that has been observed at multiple wavelengths with a diversity of techniques (imaging, interferometry, spectroscopy) tracing its dust and gas contents. The disk of HD 135344B has the remarkable property of displaying emission of warm CO gas at 4.7 micron inside the 45 AU dust gap imaged in the sub-mm. HD 135344B is also an object in which Herschel has detected [OI] emission at 63 micron. In this talk, I will discuss how the simultaneous radiative transfer modeling of multi-wavelength/multi-instrument gas and dust observations made possible to constrain the structure of the transition disk around HD 135344B, and the connection that this structure might have with planet formation.

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Matteo Guainazzi
European Space Astronomy Centre of ESA, Madrid, Spain

X-ray spectroscopy: a ruler for AGN

Abstract. The formidable energy output of Active Galactic Nuclei is produced on energy scales much smaller than the resolution power of any available telescope (radio jet emission notwithstanding). I will review in this talk how X-ray spectroscopy can overcome these shortcomings, allowing us to put constraints on the spatial scales of the main AGN ingredients (X-ray corona, accretion disk, ionised outflows, nuclear ambient gas). These constraints set the AGN structure model on a quantitative basis, and address two basic questions in AGN astrophysics: a) how does AGN feed-back on the host galaxy work? b) which are the true astrophysical foundations of the phenomenological variety of AGN types, classes and flavours?

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Anton Dmytriiev
Taras Shevchenko National University of Kyiv

Remote sensing of clouds with cosmic rays

Abstract. The optical properties of clouds is important in a wide range of scientific topics, from meteorology and climate science to astronomical observations. In particular, the presence of clouds perturbs the observation of very-high energy gamma-rays by Air Imaging Cherenkov Telescopes (IACT). Currently, the most common equipment for atmosphere exploration is a laser beam set, called LIDAR (LIght Detection And Ranging). We propose here that the Cherenkov light, produced by the cosmic rays particles penetrating into the Earth atmosphere and detected with the IACT or an air fluorescence telescope constitute itself a powerful tool for the remote sensing of clouds, complementing the LIDAR. Time-imaging of the clouds on sufficient time periods together with light curve measuring for the reflected and transmitted light, can be used for determining the multiple scattering parameters of the cloud.

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Claudio Ricci
Department of Astronomy, Kyoto University, Kyoto, Japan

The narrow iron Kα line as a probe of neutral material in Active Galactic Nuclei

Abstract. The narrow iron Kα line is the most distinctive feature in the X-ray spectra of Active Galactic Nuclei, and is possibly the most important tracer of neutral matter surrounding the supermassive black hole. One of the most interesting characteristics of the narrow Fe Kα line is the decrease of its equivalent width with the X-ray luminosity, the so-called X-ray Baldwin effect. This trend has been found by many studies of type-I AGN, and very recently also in type-II AGN (Ricci et al. 2013c).

In my talk I will review the main characteristics of the Fe Kα line, and present the results of our recent works aimed at explaining the X-ray Baldwin effect using iron-line emitting physical torus models (Ricci et al. 2013a,b), and at understanding the origin of the Fe Kα line (Ricci et al. 2013c,d).

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Andrei Bykov
A.F.Ioffe Institute of Physics and Technology, St. Petersburg, Russia

Particle acceleration and non-thermal emission of supernova remnants interacting with winds of young massive stars

Abstract. Powerful stellar winds and supernova explosions with intense energy release in the form of strong shock waves can convert a sizeable part of the kinetic energy release into fluctuating magnetic fields and relativistic particles. The starforming regions are known as a favorable site of energetic particle acceleration and could be efficient sources of nonthermal emission. We discuss models of energetic particle acceleration, interactions and nonthermal emission by supernova remnants in active starforming regions at different stages of their evolution. The high efficiency of particle acceleration in the sources implies the importance of nonlinear feedback effects in a symbiotic relationship where the magnetic turbulence required to accelerate the energetic particles is created by the accelerated particles themselves. Non-thermal emission produced by relativistic particles (both those confined in and those that escape from the cosmic accelerators) can be used to constrain the basic physical models of the sources. High resolution X-ray synchrotron imaging, combined with GeV-TeV gamma ray spectra, is a powerful tool to probe the maximum energies of accelerated particles. Future MeV regime spectroscopy will provide unique information on the composition of accelerated particles.

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Sotiria Fotopoulou
Max-Planck-Institut für Plasmaphysik (IPP), Garching, Germany

AGN Hard X-ray luminosity function and the Lockman Hole Deep Field

Abstract. The Lockman Hole field, is the area of the sky with the lowest galactic absorption, providing ideal observing conditions for extragalactic astronomy; it is the second deepest field observed by XMM-Newton with an exposure time of ~1.3Ms. I will present the first public release of deep broadband multiwavelength photometry in the Lockman Hole, discussing also the computation of photometric redshifts both for normal galaxies and X-ray selected AGN. Combining the Lockman Hole with other wide (XMM serendipitous survey, COSMOS) and deep X-ray fields (CDFS, AEGIS) we computed for the first time the evolution of the 5-10 keV AGN luminosity function. I will briefly introduce the methods commonly used to compute the luminosity function and discuss a comparison of the results between the 5-10 keV and the first meta-analysis of the 2-10 keV luminosity functions available in the literature.

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Nicolas Laporte
IRAP - Observatoire Midi-Pyrénées, Toulouse, France

Evolution of galaxies during the epoch of reionization

Abstract. Evolution of galaxies is well known up to z ~ 5, but beyond this limit and regarding the few number of galaxies confirmed by spectroscopy, their evolution is still uncertain. We have conducted two different surveys aiming to explore the high-redshift Universe: one taking benefit from the use of a lensing cluster (behind Abell 2667, to select faint sources at high-redshift) and another, the WUDS survey, using a large field of view (~400 arcmin²) to select bright sources at z > 4.5. We have used different set of data coming from HAWK-I and FORS2 @ VLT, IRAC and MIPS @ Spitzer, PACS and SPIRE @ Herschel and ACS @ HST to constrain the SED of the best candidates highlighted in our two surveys. Using all these data, we have shown the existence of extreme mid-z interlopers which can contaminate bright high-z sample and thus bias the results on the evolution of galaxies. During this talk, I will present you first the two surveys and the method I used to select high-z candidates as well as the different kind of contaminants found in these studies, and then the evolution of galaxies from z ~ 5 up to 9 as seen by the WUDS project and the survey behind A2667. I will finish my presentation by giving some perspectives, and especially the results that we can expected from futures instruments and telescopes (e.g. KMOS and MUSE @ VLT, EMIR @ GTC, JWST, Euclid and the E-ELT).

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Paolo Giommi
ASI Science Data Center, Roma, Italy

The multi-wavelength, multi-temporal (blazar) sky

Abstract. Data from different observational facilities, operating at all wavelengths across the electromagnetic spectrum and taken in different periods, is becoming increasingly available. I will show how new VO based tools, currently under development at ASDC and elsewhere, help users to exploit the potential of richer and richer multi-frequency astronomical archives. As a specific example I will present the results of a Planck, Swift and Fermi campaign to simultaneously observe samples of blazars from radio to high-energy gamma-rays and a new simplified scenario for the interpretation of the diverse observational properties that blazars exhibit in different energy bands.

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Victor Berezin
Institute for Nuclear Research, Moscow, Russia

Quantum black hole models and Schroedinger-like equations in finite differences

Abstract. It is shown that the quantization of the self-gravitating spherically symmetric thin dust shells leads to the stationary Schroedinger-like equations in finite differences. The method is elaborated for extracting the discrete mass (energy) spectra without solving the wave equations but using, instead, the analytical properties of the "correct" solutions and non-trivial causal structure of the geodesically complete space-times.

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Brian Reville
University of Oxford, UK

Particle acceleration at relativistic shocks

Abstract. I will review the first order Fermi mechanism for particle acceleration at relativistic shocks. Based on recent results of particle in cell simulations, limitations on the resulting synchrotron or synchrotron like emission are discussed.

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Juri Poutanen
University of Oulu, Finland

Fermi observation of blazars and implications for the origin of the gamma-ray emission

Abstract. Fermi Gamma-ray Space Telescope has detected hundreds of AGNs, most of them are blazars. Spectra of blazars show clear correlation with the luminosity confirming the blazar sequence. Interestingly, the GeV spectra of the brightest blazars cannot be described by a simple power law model or any smoothly curved models. A much better description is obtained with a broken power law, with the break energies of a few GeV. The sharpness and the position of the breaks can be well reproduced by absorption of gamma-rays via photon-photon pair production on He II and H I Lyman recombination continuum (LyC) and lines. This is the first direct observational proof that the blazar zone lies close to the broad-line region within a few light-months from a super-massive black hole. We also study spectral variability during flares of the brightest blazar 3C 454.3 and discover anti-correlation between the column density of the He II LyC and flux. This implies that the gamma-ray emission zone lies close to the boundary of the high-ionization part of the broad-line region and moves away from the black hole when the flux increases. Identification of the gamma-ray production with the relativistic jet, implies that the jet is already accelerated at sub-parsec distances from the central black hole, which favours the Blandford-Znajek process as the jet launching mechanism.

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Ekaterina Filippova
Space Research Institute (IKI), Moscow

Modeling and observations of flows interaction in binary systems

Abstract. My talk deals with the accretion processes in binary systems. It consists of three parts. The first one is devoted to the Classical Nova explosions. On the example of the system CI Cam it is shown that standard X-ray emission (3-10 keV) is a very useful energy band for detail study of this phenomenon immediately (in hours) after explosion and can be used for systematical discovery of such systems by X-ray surveys. The second part of the talk is devoted to the problem of interaction between an accretion disk and a stream of matter from the inner Lagrangian point in binary systems. We argue that detail analysis of this process can be used as one new tool to measure the viscosity parameter in the accretion disk. The value of this parameter is still debatable as theoretical estimations of this parameter (<=0.02) are several orders of magnitude lower than estimations from observations (~0.1-0.4). In the third part I will discuss problem of an unexpected break in low frequency region f_break/f_orb~0.2-2 in power density spectra (PDS) of X-ray flux variations of several persistent LMXB.

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Felix Fuerst
Dr. Karl-Remeis-Sternwarte Bamberg & ECAP, Uni Erlangen-Nürnberg, Germany

Accretion of clumpy stellar winds

Abstract. Neutron stars in high mass X-ray binaries accrete material from their early type optical companions. The material is highly structured, partly due to the interaction of the neutron star with the medium and partly due to the intrinsically clumpy winds of early type stars. The influence of these structures is shown exemplary on two sources. In Vela X-1 the investigation of the X-ray flux variability provides a possibility to analyze the distribution and size of these structures. I found that the distribution follows a log-normal distribution with typical clump masses on the order of 10¹⁹g. In GX 301-2 the hard X-rays emitted by the neutron star interact with the dense stellar wind, resulting in strong absorption and fluorescence lines. Using time resolved XMM-Newton spectra, I show that these features vary on time scales of a few 100s and result from the structures in the stellar wind. Using such detailed observations in combination with recently available theoretical models and simulations a better understanding of these systems and the behavior of matter under such extreme circumstances can be achieved.

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Marcos Lopez
Univ. Complutense Madrid, Spain

Chasing gamma-ray pulsars with Cherenkov telescopes

Abstract. Since the beginning of the gamma-ray astronomy from ground, all groups operating Cherenkov telescopes have pursuit eagerly the detection of pulsars in the very-high energy domain. Among them, the MAGIC telescope was built with the aim of achieving the lowest possible energy threshold, and since 2007 it has a threshold of 25 GeV. This made possible the first detection of the Crab pulsar above these energies. This detection has had a great impact in our understanding of pulsars, showing that pulsar spectra extends beyond that what was previously expected, up to at least hundreds of GeV. This rules out the popular scenario in which gamma-rays are produced in the close vicinity of the polar caps of neutron stars, and challenges also the outer gap model used to explain the pulsar spectra measured by the Fermi-LAT space detector.

In this seminar we start reviewing the current status of the gamma-ray astronomy from ground, explaining the observational techniques employed to detect those energetic photons. Next, we will introduce the models of gamma-ray emission in pulsars and will discuss their implications in the observations of pulsars from ground. Finally, we will come to a review the most relevant results obtained so far on pulsar searches with Cherenkov telescopes, and specially with MAGIC.

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Rolf Buehler
Kavli/SLAC, Stanford University, USA

Gamma-ray flares from the Crab-nebula: A new astrophysical puzzle

Abstract. The Large Area Telescope on board the Fermi Satellite observed the brightest gamma-ray flare detected to date on April 2011. The gamma-ray brightness of the nebula doubled within ~10 hours reaching peak fluxes which are a factor 30 above the average nebula flux value. Surprisingly, simultaneous observations with the Chandra Satellite and the Keck observatory revealed no counterpart to the gamma-ray emission at lower wavelength. The observations give us a new view on the particle acceleration happening within the nebula and imply that the emission region is relativistically beamed towards us.

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Dominique Eckert
ISDC Data Centre for Astrophysics, Geneva

The current processes of structure formation through merging and accretion on galaxy clusters

Abstract. Large-scale structures in the Universe form hierarchically through merging and accretion of smaller structures. As the largest gravitationally-bound structures in the present Universe, galaxy clusters are the objects where the current processes of structure formation take place. During this seminar, I will present some of the recent progress in our understanding of these processes. In particular, I will concentrate on the effects of major merging events on the general properties of galaxy clusters, such as their core properties, shocks, particle acceleration and cold fronts. I will also focus on the growth processes of galaxy clusters through accretion of small-scale structures (galaxies, groups) onto massive clusters.

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Arash Bodaghee
Space Sciences Laboratory, UC Berkeley, USA

Clustering between high-mass X-ray binaries and OB associations in the Milky Way

Abstract. We present the first ever measurement of the spatial cross-correlation function of high-mass X-ray binaries (HMXBs) and active OB associations in the Milky Way. This result relied on a sample containing 79 hard X-ray detected HMXBs and 458 OB associations. Clustering between the two populations is detected with a significance above 7-σ for distances < 1 kpc from any given HMXB. Thus, HMXBs closely trace the underlying distribution of the massive star-forming regions that are expected to produce the progenitor stars of HMXBs. The average minimum separation of 0.4(2) kpc between OB associations and HMXBs is consistent with the view that the latter have large runaway velocities (100 km/s). This suggests that the offset is mostly due to natal kicks acquired by the binary during the supernova phase (with a few exceptions). The characteristic scale of the correlation function indicates an average kinematical age (i.e., the time between the supernova and X-ray phase) of 4 Myr for the HMXB population. Despite being derived from the "grand design" of our Galaxy, these signatures of HMXB evolution are consistent with theoretical expectations and observations of individual objects.

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Sandro Mereghetti
INAF - IASF Milano, Italy

An ultra-massive fast-spinning white dwarf

Abstract. The existence of ultra-massive white dwarfs (M >1.2 M_⊙) is of particular interest for several fields of astrophysics, ranging from the properties of matter at high density, to the evolution of single and binary stars. Ultra-massive white dwarfs are also relevant as likely progenitors of Type Ia supernovae and millisecond pulsars. I will present the discovery — and new X-ray and optical observations — of a white dwarf with a mass of 1.28±0.05 M_⊙ in a peculiar binary system resulting from common envelope evolution.

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Barbara Ercolano
University Observatory Munich (USM)

The dispersal of discs around young stars

Abstract. Protoplanetary discs are the natural outcome of star formation. They hold the reservoir of material from which planets are formed and hence the timescales of their dispersal sets the timescale for planet formation. The development of theoretical models for the dispersal of protoplanetary discs around young stars has been motivated, for at least ten years, by observations suggesting a rapid transition phase (from disc-bearing to disc-less status) and inside-out dispersal. Infrared photometry from the Spitzer Space Telescope helped cement this view for solar-type stars, while at the same time raising doubts for later types, with claims of discs around M-stars homologously depleting (viscously draining) over significantly longer transition. If this were true it would mean that dispersal (and perhaps also accretion) operates differently in M-stars compared to their solar-type counterparts.

In this talk I will present a tool developed via extensive SED radiative transfer modelling for the classification of the evolutionary status of discs around M-stars using infrared photometry. Using observations of nearby clusters I will argue that, contrary to recent claims, rapid inside-out clearing is the dominant evolutionary path for M-type as well as solar type systems, further motivating the development of dispersal models that satisfy these criteria. I will finally compare and contrast predictions from current dispersal models, including different flavours of photoevaporation (EUV, FUV and X-ray) and planet formation, in the context of available observations of disc fractions in different environments as well as atomic and low-ionisation line diagnostics of hypothetical disc winds. I will conclude that there is strong observational support in favour of X-ray driven photoevaporation as a main dispersal mechanism and discuss the implications on the evolution of star-disc systems, their accretion properties and planet-making potential.

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Nicolas Fourmanoit
LPNHE - Université Paris VI

Analysis of the 5-year data sample of the SuperNova Legacy Survey

Abstract. The Supernova Legacy Survey (SNLS) is a program that aims at discovering and photometrically following hundreds of Type Ia supernovae (SNeIa). Our goal is to measure the expansion history of the Universe in order to constrain the nature of dark energy, namely its equation of state w_DE. The survey completed its data taking during summer 2008 after 5 years of program.

This talk will present the status of the program and my contribution to the project, which consisted in the analysis of these 5 years of SNLS data (SNLS-5) and in the photometry of the 419 Type Ia supernovae discovered and spectroscopically identified. For each supernova, the light curves were produced in the MegaCam natural photometric system (g_M, r_M, i_M, z_M bands), calibrated and fitted with a spectrophotometric model in order to infer the supernovae distances and populate the Hubble diagram. Furthermore a new differential photometry technique, which does not make use of any pixel resampling, has also been implemented and tested. This method preserves the pixels statistical properties and produces this way a more accurate estimation of the statistical uncertainty of the flux measurements.

A sample of supernovae with unprecedented statistics and quality is now available for cosmological analysis. With the complement of an external nearby supernovae sample, a measurement within 5% of the dark energy equation of state is thus for the first time within reach.

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Gregory Herczeg
MPE Garching, Germany

Optical and ultraviolet surveys of accretion onto young low-mass stars and brown dwarfs

Abstract. Disk accretion controls many of the most important and physically interesting processes in the formation of a star, by driving powerful outflows, braking stellar rotation, producing emission that heats and photoevaporates the disk surface, and viscously heating the disk interior where planet formation occurs. The lifetime of a disk, and consequently the time available for giant planet formation, is limited directly and indirectly by accretion. In this talk, I will review the evolution of accretion onto young stars and discuss the magnetospheric accretion paradigm. I will then present new results from a large HST/COS survey of far-ultraviolet spectra of 30 classical T Tauri stars (the DAO of Tau) and an optical survey of accretion rates in Taurus.

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Gwendolyn Meeus
Universidad Autonoma de Madrid, Spain

Protoplanetary discs around young intermediate-mass stars:

what you always wanted to know but were afraid to ask

Abstract. A circumstellar disc is a natural by-product of the star formation process, in which gas giant planets are expected to form within the first 10 Myr. These discs are initially gas-rich and optically thick, and will gradually evolve towards gas-poor, optically thin discs in which planets no longer can form. The first step into planet formation is grain growth, which will occur more rapidly in denser regions in the disc. In this talk I will address how different observations are used as a diagnostic of the disc structure or of the gas/dust properties. The dust characteristics such as grain size and crystalline fraction are mainly derived from mid-infrared Spitzer obervations, while the first far-infrared observations with the Herschel Space Observatory allow us to derive the gas temperature and gas mass still present in the disc. Finally, I will correlate the disc and dust/gas properties with the stellar properties.

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Harutyun Khachatryan
Yerevan Physics Institute, Armenia

Gamma ray bursts and CMB data analysis

Abstract. Gamma ray bursts being the most luminous objects in Universe could be used to measure distances of galaxies. We showed that after proper calibration procedure GRBs could be used as standard candles.

The Cosmic Microwave Background radiation temperature data are analyzed using the Kolmogorov stochasticity parameter. For the data obtained by the WMAP satellite we have estimated the behavior of the Kolmogorov's parameter within a non-Gaussian region, the Cold Spot, which supports its void nature. The Kolmogorov map also enables to obtain the power spectrum for the degree of randomness which can be linked with the correlation in the distribution of voids in the Universe.

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Chris Chaston
Space Sciences Laboratory, University of California, Berkeley

Auroral Particle Acceleration

Abstract. The aurora provides a local plasma laboratory for the study of processes of astrophysical significance. The conversion of electromagnetic energy into particle kinetic energy that powers the aurora is a universal plasma process thought to drive particle acceleration in a wide variety of contexts. The collision of particles, accelerated through these processes, with the upper atmosphere drives emission of auroral light in X-rays, ultra-violet and visible light. In this presentation I will show movies of these emissions and satellite observations of the acceleration process. Along the way I will describe physical models based on these observations to show how the particle acceleration processes drive the 'dancing' auroral light shows which are so well known - as well as indicating those issues which even after several decades of intensive study remain unknown. Time permitting I will also speculate on the role of similar processes in astrophysical contexts more familiar to the interests of the ISDC.

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Jean Ballet
CEA Saclay, AIM/Service d'Astrophysique, France

Particle acceleration in supernova remnants

Abstract. The cosmic-rays that pervade the Galaxy (including the Earth's environment) are thought to be accelerated in strong shocks via a diffusive mechanism (1st order Fermi) originally proposed in 1978. The best place to study that phenomenon is the blast wave created in the interstellar medium by supernova explosions. Theory has it that in young supernova remnants (where the shock velocity is several thousand km/s) the mechanism is so efficient that it transfers a sizable fraction of the kinetic energy to the accelerated particles rather than the thermal gas. This in turn modifies the shock itself, increasing the compression ratio above 4.

I will present the observational constraints on that mechanism accumulated in X-rays since the launch of the Chandra and XMM-Newton telescopes, illustrated on Cas A, Tycho, SN 1006. The most spectacular of those is the morphology of the X-ray synchrotron emission in the young supernova remnants, concentrated in a very thin shell at the blast wave. The most likely interpretation is that the accelerated particles cool down (due to the synchrotron emission itself) very fast behind the shock. This leads to the idea that the magnetic field was amplified at the shock (by the acceleration process itself) up to several hundred micro-Gauss. A second characteristic directly related to the acceleration mechanism is the width of the shell filled by the shocked ambient medium (limited inwards by the supernova ejecta).

Finally, I will discuss the gamma-ray emission of supernova remnants, in the light of the recent TeV results by HESS and Fermi. The GeV range is the best to look for hadronic emission (nuclear interactions between cosmic-ray protons and the interstellar gas, followed by π⁰ decay) in middle-aged remnants, whereas the TeV range is more sensitive to the leptonic emission (Inverse Compton on CMB, infra-red and optical photons).

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Toshikazu Ebisuzaki
RIKEN Advanced Science Institute, Japan

The JEM-EUSO Mission to Explore the Extreme Universe

Abstract. The JEM-EUSO mission explores the origin of the extreme energy comic-rays (EECRs) above 10²⁰eV and challenges basic physics to the limit, through the observation of their arrival directions and energies. It is designed to observe more than 1,000 events of EECRs above 7x10¹⁹eV in its five-year operation with an exposure larger than 1 million km²/sr/year. The super-wide-field (60 degrees) telescope with a diameter of about 2.5m looks down the atmosphere of the night-side of the earth to detect near UV photons (330-400nm, both fluorescent and Cherenkov photons) emitted from the giant air-shower produced by an EECR. The arrival direction map with 1,000 events naturally tells us the origin of the EECRs and allows us to identify the EECR sources to known astronomical objects. The comparison among the energy spectra of the spatially resolved individual sources will clarify the acceleration/emission mechanism, and also finally confirm the Greisen-Zatse'pin-Kuzmin process for the validation of Lorentz invariance up to ~10¹¹. Neutral components (neutrinos and gamma rays) can also be detected, if their fluxes are high enough. The JEM-EUSO mission is planned to be launched by a H2B rocket about 2015 and transferred to ISS by the H2 Transfer Vehicle. It will be attached to the external experiment platform of "KIBO" which was completed in July 2009 by the STS-127 mission of the space shuttle.

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Paula Texeira
ESO, Garching, Germany

Spitzer's view of NGC 2264's circumstellar disk population

Abstract. Circumstellar disks are a natural by-product of star-formation and they are the birthing sites of planetary systems. The characterization of these disks and their evolution is therefore crucial to understand and identify the initial conditions for planet formation. I will present our results on the characterization of the disk population in the young cluster NGC 2264. The disked sources were identified by their excess emission at wavelengths between 3.6 and 24 microns, and classified according to their spectral energy distribution shapes. Our results have led us to hypothesize that there may be two distinct evolutionary paths for disks: a homologous one where the disk emission decreases uniformly in near- and mid-infrared wavelengths and throughout which most sources pass, and a radially differential one where the emission from the inner region of the disk decreases more rapidly than from the outer region. Whether a disk evolves in a homologously or radially depleted fashion may be indicative of the nature of planet formation in the disk.

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Pol Bordas
IAA Tübingen, Germany

High energy processes in microquasar/medium interactions

Abstract. Emission at high and very high energies is expected from microquasars. Gamma-ray fluxes could be originated both in the inner regions of the binary system and further away in the surrounding medium. In this talk I will focus on some theoretical models based on hadronic and leptonic processes occurring at the base of the jet, as well as on the study of the non-thermal emission produced in the jet/ISM interaction regions. The predicted fluxes are compared to recent observations of some well-known systems in the TeV regime and at lower energy bands. These studies put some constraints on the physical properties of microquasars, and are used to define future observation strategies for these systems in the gamma-ray domain.

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Piero Spillantini
University and INFN, Firenze, Italy

Cosmic rays from space based observatories:

history, results and perspectives of the PAMELA mission

Abstract. A systematic research plan on cosmic rays was elaborated by NASA at the beginning of the eighties as the cosmic rays (CR) begun to be considered a fundamental tool for astrophysics and particle physics. Main programs of the plan were a magnetic facility dedicated to CR experiments on board of the Freedom Space Station (FSS) and an explorer (ACE) for the observation of CR far away from the influence of the terrestrial magnetic field. The close of the FSS program in 1991 and the long lasting shortage of means of transportation to orbit delayed or halted the space based part of the plan. In last two decades the CR observation program in space could continue with the ACE explorer and by balloon borne experiments. Lately, part of the original program in space could be recovered by the high energy gamma-ray missions AGILE and Fermi, and by the observation of the high energy CRs (in particular the antiparticle component) with the on-going PAMELA mission and the preparation of the AMS-2 mission. The preliminary results of the PAMELA mission are discussed, and the near and far future perspectives considered.

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Ann Marie Cody
Caltech, USA

Precision photometric monitoring of young low-mass stars and brown dwarfs:

shedding light on rotation, pulsation, and the star-disk connection

Abstract. Young star-forming regions are host to a variety of optically variable sources, from accreting and flaring stars to those whose light is modulated by surface spots. In addition, recent theory has suggested that a new type of variability - pulsation powered by deuterium burning - may be at work on hour timescales in young brown dwarfs and very low mass stars. Photometric studies of these diverse phenomena are key in probing the underlying physics governing the evolution of few-Myr-old cluster members. High-cadence time series provide insight into not only the stochastic nature of accretion, but also trends in rotation via monitoring of magnetic surface spots. Nevertheless, a complete characterization of variability down to low amplitudes, and particularly amongst very-low-mass (0.01-0.3 M_⊙) objects, remains elusive. The lower limit to rotation periods in young clusters is not well established, and mechanisms regulating angular momentum down through the substellar regime are not well understood. To expand the census of variability to very low mass and short timescales, as well as assess the possibility of deuterium-burning pulsation, we have carried out a dedicated monitoring campaign on confirmed low-mass members in several 2-5 Myr clusters. Using meter-class telescopes, our survey achieves sensitivity to periodic variations with photometric amplitudes down to the millimagnitude level on timescales ranging from a fraction of an hour to several weeks. We present results from the ~5 Myr Sigma Orionis cluster, including a new compilation of rotation rates and a strong correspondence between variability type and presence of a disk, as indicated by Spitzer/IRAC excesses. In contrast to previous reports of 1-4-hour variability amongst brown dwarfs, we find a dearth of periods under 10 hours. However, we identify a significant positive correlation between rotation period and mass.

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Mark McConnell
University of New Hampshire, USA

The Status and Future Prospects for Gamma-Ray Polarimetry

Abstract. Polarimetry remains one of the last unexploited aspects of X-ray and gamma-ray astronomy. This field had been largely dormant since the first X-ray measurements of the Crab polarization in the 1970's. In recent years, however, there have been several reports of polarization measured in gamma-ray bursts and solar flares. Although these results have all been of marginal significance, they have spurred a renewed interest in high energy polarimetry. This interest has been further piqued by the latest reports of polarized emission from the Crab as measured by INTEGRAL. Here I shall review the status of high energy polarization measurements and some of the theoretical motivations. I will also review the ongoing work at the University of New Hampshire, where we have been involved in high energy polarimetry for several years. Our efforts have included both observational work (e.g., using RHESSI to look for solar flare polarization) and experimental work (developing dedicated instrumentation for high energy polarization measurements). Our experimental efforts have recently culminated in a balloon program that we call GRAPE (Gamma-Ray Polarimeter Experiment), which is scheduled for its first scientific balloon flight in the fall of 2011.

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Heike Prokoph
DESY, Zeuten, Germany

Gamma-hadron separation using pixel timing information for HESS and CTA

Abstract.

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Lucia Pavan
Astronomy Department, University of Wisconsin, Madison, USA

Magnetars: twists in the magnetosphere

Abstract. Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs) are some of the most energetic (and puzzling) X-gamma ray sources in our Galaxy. Both classes of objects are thought to be extremely magnetized neutron stars, and are well described by the "magnetar model". The external fields of AXPs and SGRs inferred from their periods (~ 10 s) and spin-down rates (up to ~ 10^-10 s/s) are of order 10¹⁴-10¹⁵ G. The (persistent) emission of these objects can be interpreted as photons thermally emitted by the neutron star surface, and reprocessed via resonant cyclotron scatterings (RCS) by (mildly) relativistic charges flowing in a "twisted magnetosphere". Models investigated up to now are based on "globally twisted" magnetostatic equilibria, in particular on force-free solutions obtained by twisting an initially dipolar field. Although such RCS spectral models proved quite successful in explaining the persistent emission from the magnetar candidates, there are indications that, at least in some cases, the twist is localized and not necessary global. I shall present more general force-free solutions for a twisted magnetosphere, with particular regard to higher-order twisted multipoles. The phase-resolved spectra and energy-dependent lightcurves obtained with a simple model of a locally sheared field are confronted with the INTEGRAL observations of the AXPs 1RXS J1708-4009 and 4U 0142+61. Some Fermi observations of magnetars will also be discussed.

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Christian Farnier
LPTA, Université Montpellier 2

Fermi and H.E.S.S. searches for a dark matter annihilation signature in dwarf spheroidal galaxies

Abstract. Although it is now established beyond reasonable doubt that non-baryonic dark matter (DM) is needed in order to explain results obtained by several experiments, the nature of these new particles is still unknown. Self annihilation of DM particles can lead to several indirect signatures, especially high energy gamma rays. Dwarf spheroidal galaxies provide among the best targets for searches of a signal from a DM annihilation. These objects are highly dominated by DM, local and do not host bright, high energy astrophysical sources. The H.E.S.S. array of 4 imaging atmospheric Cherenkov telescope is a ground based experiment with unprecedented sensitivity for gamma-ray observations above 100 GeV. Fermi, successfully launched on June 11, 2008, is conducting an all sky gamma-ray survey in the 20 MeV up to 300 GeV energy range with unparalleled sensitivity. I will present the searches for a DM annihilation signature in dwarf spheroidal galaxies conduct by these two experiments.

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Andrea Tramacere
SLAC, Stanford

Spectral analysis of Fermi-LAT data

Abstract. I will show how to perform a spectral analysis of the Fermi-LAT data, starting from the data selection, and the source detection. I will show ho to use the unbinned likelihood analysis and which are the possible biases.

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Andrea Tramacere
SLAC, Stanford

Phenomenological approach to the multi-wavelength study of blazars

Abstract. I will discuss a phenomenological approach to the multiwavelength study of Blazar emission. In the first part I will show how to use UV/X-ray data to look for signature from stochastic acceleration processes in HBL objects and how these features can be linked to predict the GeV/TeV emission, and how the intrinsic spectral curvature is relevant to understand the EBL issue. In the second part I will discuss the multiwavelength emission from FSQRs in the framework of the external Compton scenario. I will show how the changes in different physical parameters can account for different patterns in the spectral evolution. showing predictions for the opt/UV, X-ray, and gamma emission.

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Matteo Balbo
INFN, Padova

Pulsar observations and Fermi/LAT instrumental application

Abstract. The Large Area Telescope (LAT) aboard of the Fermi Gamma-ray Space Telescope started regular sky survey operations on August 13, 2008. Its efficiency, resolution and low dead time make it an ideal tool for the study of gamma-ray emission from pulsars. Exploiting radio and gamma-ray ephemerides it is possible to get data samples of gamma-ray events practically free of contaminations. Pulsars are further excellent candidates for the calibration of some features of the response of the LAT. Moreover recent developments in the trigger mechanism of Cherenkov telescopes allow those the detection of pulsation in the very-high-energy gamma-ray range and LAT observations of the same objects promise to be helpful in the calibration of Cherenkov Telescopes, in an approach that does not depend exclusively on Monte Carlo simulations.

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Giulia Vannoni
CEA, Saclay

Diffusive shock acceleration in radiation dominated environments

Abstract. A generic framework will be presented to study self-consistently the acceleration of particles at non-relativistic shocks in presence of strong radiative losses. The effects of energy losses on the shape of the resulting particle spectrum will be reviewed for several astrophysical environments where the radiation pressure dominates over the magnetic pressure. I will present results for both electrons undergoing intense inverse Compton losses, and show the impact due to the changing features of the inverse Compton scattering from the Thomson to the Klein-Nishina regime, on the spectrum of accelerated electrons and their broadband emission; and protons accelerated in galaxy clusters losing energy in the interaction with the Cosmic Microwave Background radiation. The secondary products from pair production and photomeson processes interact with the same photon field and the background magnetic field, producing broadband electromagnetic radiation from radio to gamma-rays.

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Malgorzata Sobolewska
University of Crete, Heraklion

Long term X-ray spectral variability and spectral-temporal correlations in AGN

Abstract.

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Barbara de Marco
SISSA, Trieste

Variable Fe K features in bright radio-quiet AGNs of the FERO sample

Abstract.

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Adam Amara
ETH Zürich

Gravitational Lensing with Euclid:

Prospects for moving beyond LCDM cosmology

Abstract.

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Jean-Philippe Lenain
Observatoire de Paris-Meudon

VHE gamma-rays from AGN with H.E.S.S.:

multi-wavelength studies and radiative modeling

Abstract. With the advent of the current generation of imaging atmospheric Cherenkov telescopes, active galactic nuclei (AGNs) are prime targets for observations of extragalactic sources in the very high energy (VHE; E>100GeV) domain.

In this seminar, I will present my work within the H.E.S.S. collaboration during my PhD thesis, concerning multi-wavelength (MWL) studies of AGNs and development of radiative models. A synchrotron self-Compton (SSC) model was developed specifically for misaligned blazar-like sources. Interpretation of the VHE gamma-ray emission of M 87, as well as some predictions for Cen A, will be discussed.

I will also present the recent MWL campaign of PKS 2155-304 conducted in July-August 2006, which revealed an extreme variability at VHE. A time-dependent SSC model applied to this rich data set will be discussed, as well as the recent discovery of two AGNs: RGB J0152+017 and Cen A, the latter firmly establishing radio galaxies as a new class of VHE emitters.

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Andrew Taylor
Max-Planck Institut für Kernphysik, Heidelberg

Signatures of UHECR Sources

Abstract. The losses ultra high energy cosmic rays (UHECR) undergo both in their source environment and outside the source in extragalactic space are discussed. For UHECR sources the example case of AGN is used. Uncertainties in the environments both inside and outside the source are addressed, with the corresponding uncertainties in the subsequent interaction rates being highlighted. Signatures of the presence of these particles in these environments are explored, with the photon fraction of the arriving UHECR at Earth being used to demonstrate the effectiveness of this approach.

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Joanna Brown
MPE Garching, Germany

Childhood to Adolescence:

Dust and Gas Clearing in Protoplanetary Disks

Abstract. The evolutionary processes transforming massive, gas-rich circumstellar disks into tenuous, gas-poor debris disks are still not well understood. During this crucial interval, planet(esimal)s form and the remaining disk material is accreted or dispersed. Mid-infrared spectrophotometry of proto-planetary disks have revealed a small sub-class of objects with spectral energy distributions (SEDs) that suggest the presence of large inner gaps with low dust content, often interpreted as a signature of young planets. However, SEDs are notoriously difficult to interpret as multiple physical scenarios can result in the same SED. We present some of the first direct evidence supporting the gap hypothesis in the form of SMA 880 micron continuum maps resolving inner disk holes. The holes, first discovered through mid-IR spectroscopy, have radii in the 20-50 AU range and are in excellent agreement with predictions from SED modeling. However, despite the dust depletion, high resolution spectra from Keck NIRSPEC and VLT CRIRES reveal that CO gas is often present in the inner disk regions. In combination with modeling, these spatially resolved data help constrain the evolutionary processes active in these unusual disks.

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Kevin Briggs
ETH Zürich, Switzerland

The Orion Nebula's 2 million degree bubble

Abstract. The Orion Nebula is one of astronomy's best-loved, most-photographed and well-studied objects. As the closest example of a rich star-forming region, it gives us perhaps the best insight into the environment in which our own solar system formed. Recent X-ray observations have serendipitously revealed a hitherto well-kept secret: a two-million degree plasma filling the cavity associated with the Nebula. I describe the discovery, origin and implications of this hot bubble, which appears to have burst, providing a continuous source of hot, enriched material to the interstellar medium, complementing the larger, infrequent discrete inputs from supernova explosions.

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Mária Süveges
Ecole Polytechnique Fédérale de Lausanne

Pattern recognition for climate extremes

Abstract. The huge impact of catastrophic events like windstorms, heavy rainfall or heatwaves on economy and human life and their random nature makes their investigation one of the hottest topic of statistics. What sea level will be likely to be exceeded only once during the next thousand years at a specified dyke on the shores of the Netherlands? How often would a windstorm of the strength of Lothar sweep over a particular industrial site or large city? How often can we expect long heatwaves similar to that of the summer of 2003?

There are now many statistical models that describe various aspects of such extreme events: their size distribution, their spatial distribution, their tendency to arrive in groups. However, there is at present no method that can estimate both the sizes of the extremes in simultaneous time series and their clustering, and remains at the same time flexible enough to be generally applied. A model, called the multivariate maxima of moving maxima (M4) process has the potential to allow such an estimation procedure. This process models the neighbourhoods of extreme events by classifying them into types. Risk estimation and prediction can be built on the estimated frequency and profile of these types. There are many difficulties in fitting the model: we don't know exactly the onset and the end of the extremal clusters, the clear profiles of the theoretical model are blurred by many effects in the observations, and the type of an observed extreme cluster is unknown. We propose solutions to these problems, sketch the estimation procedure, and discuss the present problems and the future development of the model.
This work is joint with A. C. Davison.

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Cédric Foellmi
Laboratoire d'Astrophysique de Grenoble, France

Quantum of Quasars:

The hard branch of microquasars and their potential for quantum astronomy

Abstract. Microquasars are black-hole binaries with jets. Nowadays, they are studied mostly in X- and gamma-rays where the inner accretion disk emits most of its energy. I will present new theoretical results from the model of Grenoble. In particular, I will show how this new model produce 3 disk solutions among which a very hot optically thin geometrically thick inner disk. This solution can be used to model the hard branch of the hysteresis diagram. I will show that the theoretical hard branch limits and its tilt represent new and strong(er) constraints on the behavior and caracteristics of microquasars accretion disk. I will finish by trying to replace microquasar's observations on a more global context. I will then present some speculative ideas about their potential as best targets for what is now called quantum astronomy, opened up 50 years ago by the intensity interferometry.

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Anthony Dean
University of Southampton, UK

Pulsar Wind Nebulae and Polarized Gamma-Ray Emission from the Crab

Abstract. Pulsar Wind Nebulae (PWN) are powerful soft gamma-ray sources that emit typically 1% of the pulsar's spin down energy in the 20 to 100 keV domain. During the course of the Galactic plane survey the INTEGRAL mission has detected about 10 PWN, all of which are associated with energetic young pulsars. A brief review of gamma-ray emitting pulsar/PWN systems in the context of the physical attributes of the parent pulsars will be followed by a more detailed discussion of the recent INTEGRAL detection of a highly polarized gamma-ray flux from the Crab nebula. Within an interpretation of this result two main themes will emerge during the talk: an attempt to locate the position of origin of the gamma-rays in the context of the complex morphological structures (jets, torus, etc.) inherent to the PWN systems; and the likely physical processes involved.

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O. Ruchaysky and A. Boyarsky
EPFL, Lausanne

Cosmological and astrophysical bounds on light dark matter

Abstract. A number of particle physics models predict a dark matter candidate with the mass in the keV range. We will discuss astrophysical and cosmological bounds on such dark matter candidates. In particular, we will review constraints on their properties, obtained using the Lyman-alpha forest data in combination with WMAP 5-years results.

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Dmytro Iakubovskyi
BITP, Kiev, Ukraine

Thermal and non-thermal X-ray emission from SN 1006

Abstract. A number of important processes taking place around strong shocks in supernova remnants (SNRs) depend on the shock obliquity - the angle between the shock normal and the interstellar magnetic field (ISMF). To study these processes, we select SN 1006 - the first SNR with recognized non-thermal emission. Its rather simple morphology, the exact knowledge of its age, and its evolution in low interstellar medium densities (due to high galactic latitude) make it an ideal laboratory to study these processes. We investigate the spatial distribution of X-ray and radio emission, observed with XMM-Newton and VLA/Parkes, respectively. Analyzing the radio map we conclude about the possible direction of ISMF depending on shock acceleration (aspect angle). When combining X-ray and radio data together, we model the emission from regions close to the shock as the sum of thermal and non-thermal components. By subtracting the properly scaled non-thermal emission, we produce the "purely thermal" image which indicates the separation between purely thermal and non-thermal emission. The possible implications of these results are discussed.

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Dmytro Iakubovskyi
BITP, Kiev, Ukraine

Sterile neutrino Dark Matter

an overview and detection perspectives with INTEGRAL/JEM-X

Abstract. One of the most plausible hypotheses of the Dark Matter (DM) nature is that it consists of elementary particles. However, none of the particles in frames of the Standard Model is able to explain the observed DM properties. Therefore, to build the DM particle candidate, one should extend the Standard Model. Among the proposed DM candidates are the right-handed (sterile) neutrinos, which could also explain the observed neutrino oscillations and the baryon asymmetry of the Universe. In frames of sterile neutrino model, there exists a compact window of parameters, which could be investigated by several ways. One of them is to detect the unidentified hard X-ray or gamma-ray line - the result of sterile neutrino DM decay. The conditions for a "best effective detector" are derived. It is shown that JEM-X, due to its exceptionally high FoV, can serve as an effective detector for the search of DM decay line, especially in the 10-20 keV energy range, in which the effective areas of both XMM-Newton and INTEGRAL/SPI are faded out.

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Iurii Sushch
Astronomical Observatory of Kiev University, Ukraine

Modelling of the Vela Complex

Including the Vela Supernova Remnant, the Binary System γ² Velorum and the Gum Nebula

Abstract. We study the geometry of the Vela complex including the Vela supernova remnant (SNR), the binary system γ² Velorum and the Gum Nebula. We argue that the asymmetry between the North-East and South-West parts of the Vela SNR could be explained by the presence of a stellar wind bubble blown by the Wolf-Rayet (WR) star nearest to the Earth in the γ² Velorum system. Detection of the boundary of the stellar wind bubble of γ² Velorum enables us to derive an upper limit of 45 solar masses on the initial mass of the Wolf-Rayer star. The low initial mass of the WR star implies that the luminosity of nuclear line of ²⁶Al, produced by the γ² Velorum is below the detection limit of current telescopes.

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Enrico Bozzo
Osservatorio Astronomico di Roma, Italy

Hunting for Magnetars in binary systems

The case of Supergiant Fast X-ray Transients

Abstract. In this presentation I'll summarize some aspects of the wind accretion theory in high mass X-ray binaries hosting a magnetic neutron star and a supergiant companion. In particular, I'll concentrate on the different types of interaction between the inflowing wind matter and the neutron star magnetosphere that are relevant when accretion of matter onto the neutron star surface is largely inhibited; these include the inhibition through the centrifugal and magnetic barriers. I'll show that very large luminosity swings (~10⁴ or more on time scales as short as hours) can result from transitions across different regimes.

The activity displayed by supergiant fast X-ray transients (SFXTs), a new class of high mass X-ray binaries in our galaxy recently discovered with INTEGRAL, has often been interpreted in terms of direct accretion onto a neutron star immersed in an extremely clumpy stellar wind. I'll show here that the transitions across the magnetic and/or centrifugal barriers can explain the variability properties of these sources as a results of relatively modest variations in the stellar wind velocity and/or density.

According to this interpretation I'll argue that supergiant fast X-ray transients which display very large luminosity swings and host a slowly spinning neutron star are expected to be characterized by magnetar-like fields, irrespective of whether the magnetic or the centrifugal barrier applies. Supergiant fast X-ray transients might thus provide a new opportunity to detect and study magnetars in binary systems. Finally, I'll also discuss some of the latest results from a recent observational campaign carried out with XMM-Newton on a number of SFXT sources.

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Timothé Boutelier
Laboratoire d'Astrophysique de Grenoble, France

An inhomogeneous jet model for the rapid variability of TeV blazars

Abstract. We present a new time-dependent inhomogeneous jet model of non-thermal blazar emission, which reproduces the entire spectral energy distribution together with the rapid gamma-ray variability. Ultra-relativistic leptons are injected at the base of a jet and propagate along the jet structure. We assume continuous reacceleration and cooling, producing a relativistic quasi-Maxwellian (or "pile-up") particle energy distribution. The synchrotron and synchrotron self-Compton jet emissivities are computed at each altitude. Klein-Nishina effects as well as intrinsic gamma-gamma absorption are included in the computation. Due to the pair production optical depth, considerable particle density enhancement can occur, particularly during flaring states. Time-dependent jet emission can be computed by varying the particle injection, but due to the sensitivity of pair production processes, only small variations of the injected density are required during the flares. The stratification of the jet emission, together with a pile-up distribution, allows significantly lower bulk Lorentz factors, compared to the ones obtained with the commonly used one-zone models, in better agreement with observational and statistical constraints. Applying this model to the case of PKS 2155-304 and its big TeV flare observed in 2006 with H.E.S.S., we can reproduce simultaneously the average broad-band spectrum of this source from radio to TeV, as well as the TeV light curve of the flare with a bulk Lorentz factor lower than 15.

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Francesca Volpe
LLR Ecole Polytechnique, France

PKS 2155-304: long term H.E.S.S. observations and spectacular outbursts results

Abstract. The spectacular increase of the sensitivity of Cherenkov telescopes allowed the detection of 22 blazars emitting very high energy (VHE) gamma-rays. The discovery of very distant blazars has important implications on the understanding of the acceleration processes in blazars and on the indirect measurement of the extragalactic background light. Unfortunately, most of the discovered blazars are weak TeV sources (typical emission around a few percent of that of the Crab nebula), but some of them sometimes exhibit spectacular flares. The High Energy Stereoscopic System (H.E.S.S.) has contributed with its sensitivity to the detection of distant blazars in the TeV range. With monitoring campaigns, H.E.S.S. has also searched for flux and spectral variability in blazars on timescales ranging from months down to minutes. Since 2003, H.E.S.S. has monitored PKS 2155-304 (one of the brightest and best-studied VHE gamma-ray sources) and in July 2006 has detected this source in an active state, followed by the detection of two extraordinary flares on July, 28th and 30th, with a temporal resolution of the order of the minute. Results from this H.E.S.S. campaign will be presented here with particular emphasis on the evidence for a quiescent state in this source and on the spectral and flux variability. The unprecedented statistics collected during the flaring period (July 28-31, 2006) allowed a temporal variability study that will be presented here, indicating for the first time in this energy domain that the strong variability can be accounted for as a realization of a random stationary Gaussian process with the logarithm of the fluxes being the relevant Gaussian variable. Finally, an X-ray observation of PKS 2155-304 with the Chandra satellite taken during the second flare, will be presented.

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Iosif B. Khriplovich
Budker Institute of Nuclear Physics, Novosibirsk, Russia

Quantized black holes, their spectrum and radiation

Abstract. The maximum entropy of quantized horizon is demonstrated to be proportional in the classical limit to its area. The general structure of the horizon spectrum is derived. The discrete spectrum of thermal radiation of a black hole fits the Wien profile. The natural widths of the lines are much smaller than the distances between them. The total intensity of thermal radiation is estimated.

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Grzegorz Wrochna
Soltan Institute for Nuclear Studies Otwock-Swierk, Poland

Prompt optical observations of GRB 080319B

Abstract. GRB 080319B was the brightest explosion ever observed. Visible to human eye, happened 7.5 Gy away - half across the Universe. It was imaged with fast cameras, for the first time making the movie of a black hole formation. Precise measurements spanning through 9 orders of magnitude in intensity and 11 in wavelength, challenge todays GRB theories. How long do we need to wait for the next opportunity like that? New ideas for prompt optical observations will be presented.

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Laure Fouchet
ETH Zürich, Switzerland

The effect of a planet on the dust distribution in a 3D protoplanetary disk

Abstract. With the coming new generation of observation facilities such as ALMA, we hope to discover new planets by direct imaging. For instance, Wolf & D'Angelo (2005) showed that it will be possible for ALMA to detect the gap created by a Jupiter mass planet embedded in a circumstellar disk and orbiting at 5 AU from a solar mass star in a region 140 pc away from the observer. Their study relies on simulations of a pure gaseous disk and the assumption that dust is well-mixed to the gas. But, depending on grain size, this assumption is not always valid and grains decouple from the gaseous motion. We instead use a 3D, two-fluid SPH code and show that the gap created in the dust layer is much more striking than in the gas. We also note a pile up of dust at the external edge of the gap. We therefore expect that gaps created by planets even lighter than 1 Jupiter Mass will be observable with ALMA. I will present our detailed results for different grain sizes and planet masses. Each study will be done for the two different cases of a Minimum Mass Solar Nebula (MMSN) and a standard T Tauri disk, i.e. a compact disk and a more radially extended one. And I will finish with preliminary synthetic images of these structures.

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Chris Done
University of Durham, UK

Accreting black holes

Abstract. Accretion flows light up the regions of extremely curved spacetime around black holes, transforming the darkest objects in the Universe to the brightest. Astrophysical black holes come in two distinct size scales, with supermassive black holes powering the distant quasars, shaping galaxy formation and the growth of structure in the early Universe, while stellar mass black holes form in the last stages of stellar evolution of massive stars. While there is a large range of mass (and presumably spin) in the AGN, the stellar mass binaries form a remarkably homogeneous set so provide a perfect laboratories for studying black hole accretion flows. Yet the properties of the accretion flow should be fairly scale invariant, so what we learn about accretion flows from stellar mass systems should also be applicable to the supermassive black holes. I will review recent progress in understanding Galactic binary systems, in particular how the bewildering variety of spectral, timing and jet properties - the so called 'spectral states' - can be explained by changing the nature (and hence geometry) of the accretion flow, and then discuss how these apply to AGN.

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Andrzej Zdziarski
N. Copernicus Astronomical Center, Warsaw, Poland

The high-mass X-ray binaries Cyg X-3 and Cyg X-1

Abstract. I will discuss results of fitting the X-ray spectra of Cyg X-3 and the implications for the absorbing stellar wind. We measure the mass-loss rate and find it to agree with independent estimates. The wind is two-phase, with the filling factor of the clumpy part of ~0.01. The bolometric luminosity indicates the presence of a black-hole. Then I will discuss a study of precessional variability of Cyg X-1 and a discovery of an accretion bulge. Comptonization anisotropy of the X-ray emission of a precessing disc and Doppler anisotropy of the radio emission of a precessing jet explain well the superorbital periodicity of Cyg X-1. We find the disc tilt of ~10-20 degrees and the jet velocity of ~(0.3-0.5)c. Then we discover a dependence of the X-ray orbital modulation on the superorbital phase, which is well explained by absorption in a bulge at the disc outer edge.

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Daniela Dorner
Julius-Maximilian-Universität Würzburg

MAGIC view of PG 1553+113

Abstract. With the current generation of Cherenkov telescopes the number of sources discovered in the very high energy (VHE, > 50 GeV) range has increased to 75. From the 20 active galactic nuclei (AGN) detected so far, studies on the physics in these objects can be carried out. This presentation focusses on the Blazar PG 1553+113, which has been observed for about 80 hours with the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescope between April 2005 and April 2007. The data of 2005 up to April 2006 have been re-analysed with an improved analysis taking the arrival times of the signals into account. The result from this is presented together with results of data from April 2006 to April 2007. The data of 2007 include a better timing resolution, due to faster FADCs, providing a better sensitivity of the measurement. In July 2006 data have been taken during a multi-wavelength (MWL) campaign. For the MAGIC data of these campaign a method to correct for strong atmospheric absorption has been developed, as this data suffer from the effect of the Saharan Air Layer. Applying this correction, the results can be used for a MWL study together with the data of the X-ray satellite Suzaku and the optical telescope KVA. The results of the study of flux and spectral variability between 2005 and 2007 are presented.

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Francesco Fontani
INAF-Istituto di Radioastronomia, Bologna (Italy)

The initial conditions in the high-mass star formation process

Abstract. Pre-stellar cores are dense and cold molecular condensations where the star formation process will probably take place. Protostars are born from gravitational collapse of these cores, so that understanding their internal structure allows one to constrain the initial conditions of the star formation process. So far, several examples of low-mass pre-stellar cores have been identified, but a sample of high-mass pre-stellar cores is lacking. Bearing in mind that high-mass stars form in clusters, we have searched for cold and dense spots close to some well-known high-mass protostellar objects, adopting the investigative techniques successful in the identification of low-mass pre-stellar cores (i.e. high values of the column density ratio N(N₂D⁺)/N(N₂H⁺) and of the CO depletion factor). I will present both single-dish and interferometric millimeter and sub-millimeter observations that have allowed us to identify pre-stellar core candidates in the studied sources.

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Dmitry Semikoz
AstroParticule et Cosmologie (APC), Université Paris 7

Correlation of ultra-high energy cosmic rays with nearby astrophysical sources observed by the Pierre Auger Observatory

Abstract. The Pierre Auger Observatory (close to completion of construction in Argentina) has collected ~9000 km² sr yr of exposure at the energies E>10¹⁹ eV during the period 2004-2007. This is the highest exposure achieved by any ultra-high-energy cosmic ray (UHECR) experiment. The large exposure has enabled to detect the so-called Greisen-Zatsepin-Kuzmin (GZK) cut-off in the UHECR spectrum with a significance of more than 6 sigma. The detection of this cut-off provides evidence for an astrophysical origin of UHECR sources. In this talk I will present recent results on correlation of arrival directions of UHECR events with sky positions of nearby astronomical sources. These results open a new field of UHECR astronomy.

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Susumu Inoue
National Astronomical Observatory of Japan

Hard X-ray Emission from High Energy Nonthermal Processes in Clusters of Galaxies

Abstract. There are good reasons to believe that clusters of galaxies contain different populations of high-energy particles that can lead to interesting nonthermal X- ray and gamma-ray emission. I will discuss various theoretical possibilities for hard X-ray emission from electrons, protons and their secondary products, the observational prospects, and their relation to GeV-TeV gamma-ray and ultra-high-energy cosmic ray production.

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André Csillaghy
Institute of 4D-Technologies (i4Ds), University of Applied Sciences Northwestern Switzerland

The Herschel Common Software System: yet another tool to bother astronomers?

Abstract. In this presentation I will try to convince that there is more behind. The Herschel Common Software System (HCSS), and its extensions to support the PACS, SPIRE and HIFI intstruments of ESA's Herschel spacecraft to be launched in 2008, is currently being developed to offer to the astronomical community the means to do science with Herschel data products, without any licences. The system has a double function. On one hand, it supports the commissioning of the instrument, the validation of the observing modes, and the calibration of the instruments. On the other hand, it allows astronomers to use the same software, in an interactive environment, to analyze the data. Furthermore, the system also provides toolboxes to develop data processing algorithms in a scripting environment. I will give a biased view of the system, focusing on the HIFI instrument, and emphasizing the role we play in the calibration pipeline and the spectral toolboxes.

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Dieter Horns
Institut für Astronomie und Astrophysik, Eberhard Karls Universität, Tübingen

Ground based Cherenkov telescopes: Data reduction and analysis

Abstract. Ground based Cherenkov telescopes have become useful tools for astroparticle physics and multi-wavelength astrophysics. However, the instruments' data are only available for the consortia operating these "experiments". Within these consortia a multitude of approaches to data analysis have been developed and implemented. Aim of this talk is to provide a look behind the scenes: how the data are reduced and analysed. Finally, I will discuss possible strategies on how to make data available to a wider community of Astro(particle)physicists.

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Jan-Uwe Ness
Arizona State University, USA

The X-ray view of Classical Novae

Abstract. Classical Novae are thermonuclear explosions that occur in stellar binary systems consisting of a solar-like star and a so-called White Dwarf, an old stellar object that has shrunk to a degree of compactness that it consists only of degenerate matter after having lost all of its hydrogen. Mass transfer from the solar-like star to the White Dwarf provides new hydrogen-rich material that will ignite a nuclear fusion reaction chain. While this principle is always the same, all Classical Novae observed so far have been quite different in their evolution. X-ray observations reveal central pieces of information as they allow insights into the hottest processes. I will give a description of the typical evolution of Classical Novae and show examples of X-ray spectra during the different phases of evolution. A more detailed view also illustrates how different the evolution can be when different system parameters are given.

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Stan Owocki
Bartol Research Institute, University of Delaware, USA

Magnetic Models of Circumstellar Clouds around Hot, Massive Stars

Abstract. Recent advances in spectropolarimetric techniques have led to direct detection of moderate to strong (100-10,000 G), tilted dipole magnetic fields in several massive stars. Using a combination of analytic and numerical MHD models, this talk will focus on the role of such magnetic fields in channelling, and sometimes confining, the radiatively driven mass outflows from such stars. In particular, I discuss how the resulting "magnetically confined wind shocks" can explain the moderately hard X-ray emission seen from the O7V star Theta-1 Ori C, and how the trapping of material in a "rigidly rotating magnetosphere" can explain the periodically modulated Balmer line emission seen from the magnetic B2pV star σ Ori E. I also discuss how magnetic reconnection heating from episodic centrifugal breakout events might explain the occasional very hard X-ray flares seen from the latter star. I conclude with a brief discussion on the generation of hot-star fields and the broader relationship to other types of magnetospheres.

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Jamie Shiers & Patricia Mendez Lorenzo
CERN, IT Division

The Worldwide LHC Computing Grid - What? Why? How?

Abstract.
1st talk: In order to process and analyse the multi-PetaBytes of data from the LHC - the world's largest scientific machine - a worldwide grid service has been established, building on two main production infrastructures: those of the Open Science Grid (OSG) in the Americas, and the Enabling Grids for E-sciencE (EGEE) Grid in Europe and elsewhere. Over the past 3 years, the Worldwide LHC Computing Grid (WLCG) services have undergone a series of so-called 'service challenges' designed to ramp the service up to the required degree of availability and performance and to trigger medium/long term planning of the various sites and regions involved. Detailed service and availability targets have been drawn up by the WLCG collaboration and form part of the Memorandum of Understanding (MoU) that is signed by all participating sites. This talk summarises the main lessons learnt from deploying WLCG production services. In particular, we discuss how the somewhat ambitious targets laid out in the MoU are addressed and the various deployment strategies that are required. Finally, a simple analogy is drawn with the Web in terms of usability - what do we need to achieve to cross the chasm from small-scale adoption to ubiquity?

2nd talk: The computational and storage capability of the Grid are attracting several research communities. This talk discusses the general patterns observed in supporting new applications and porting them on the EGEE environment. We present the general infrastructure we have developed inside the application and support team at CERN (PSS and GD groups) to merge in a fast and feasible way all these applications inside the Grid, as for example Geant4, HARP, Garfield, UNOSAT or ITU. All these communities have different goals and requirements and the main challenge is the creation of a standard and general software infrastructure for the immersion of these communities onto the Grid. This general infrastructure does effectively "shield" the applications from the details of the Grid (the emphasis here is to run applications developed independently from the Grid middleware). On the other hand, it is stable enough to require few control and support by the members of the Grid team and also of the members of the users communities. Finally, it is flexible and general enough to match the requirements of the different productions without including major changes in the design of the tool.

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Thierry Lanz
University of Maryland, USA

Searching for Type Ia Supernova Progenitors

Abstract. The identification of progenitors of supernovae of type Ia (SN Ia) remains elusive. I will review the case for single-degenerate systems versus double-degenerate systems. A promising channel leading to a SN Ia event involves accreting white dwarfs that sustain steady nuclear burning. They are observed as close binary X-ray sources with a supersoft spectrum (CBSS). I will discuss the properties of these systems based on an on-going multi-wavelength (Spitzer, Chandra and XMM-Newton) study of CBSS.

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Dmytro Iakubovskyi & Denis Malyshev
BITP, Kiev, Ukraine

Sterile neutrino Warm Dark Matter constraints from XMM-Newton and INTEGRAL/SPI observations

Abstract. The existence of right-handed "sterile" neutrinos can explain such phenomena as neutrino oscillations, origin of dark matter particles and baryon assymetry of the Universe. We present the upper limits on "sterile" neutrino parameters, obtained from direct observations of dark matter clusters (central parts of Milky Way and Andromeda galaxies), and discuss the physical consequences of these limits.

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Maurizio Falanga
CEA Saclay, France

General Relativistic Flux Modulations from Disk Instabilities in Sagittarius A*

Abstract. The compact radio source Sgr A* at the center of our Galaxy provides the most compelling evidence for the existence of supermassive black holes. Both near-IR and X-ray flares have been detected from this object, sometimes modulated with a (quasi)-period of ~17-20 minutes, suggesting an emission region at ~3 R_S, where R_S is the Schwarzschild radius for an inferred mass of ~3.7 10⁶ M_Sun. The latest X-ray flare, detected with XMM-Newton, is notable for its detailed lightcurve, which not only yields the highest quality period thus far, but also reveals important structure reflecting the geometry of the emitting region. Recent simulations of Sgr A*'s disk have revealed the growth of a Rossby wave instability (particularly in its MHD form), that enhances the accretion rate for several hours, possibly accounting for the observed flares. In this seminar, I will present how I carry out state-of-the-art ray tracing calculations in a Schwarzschild metric to determine as accurately as possible the lightcurve produced by general relativistic light-bending, lensing effect, doppler effect and travel time delay during such a disruption. The Rossby-wave induced spiral pattern in the disk is an excellent fit to the data, implying a disk inclination angle of ~77°. Note, however, that if this association is correct, the observed period is not due to the underlying Keplerian motion but, rather, to the pattern speed. The favorable comparison between the observed and simulated lightcurves provides important additional evidence that the flares in Sgr A* are produced merely a handful of Schwarzschild radii above the event horizon.

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Raphael Lamon
Univ. of Ulm, Germany

Aspects of Dark Matter: Gravitinos, the CMB and new results from loop quantum gravity

Abstract. Part I: After 10⁵-10⁸ sec, supersymmetric particles may have decayed to gravitinos, releasing energy that distorted the CMB. The goal is to give approximate masses of supersymmetric particles determined by the constraints from COBE.

Part II: New results from Loop Quantum Gravity suggest that dark matter, inflation and particles may be illusory effects from a deeper theory. This part should be a non-technical overview of these recent results.

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Andrzej Zdziarski
N. Copernicus Astronomical Center, Warsaw, Poland

4U 1820-303: a physical laboratory in the sky

Abstract. 4U 1820-303 is an X-ray binary with a very short 11-min orbital period. It consists of a white dwarf and a neutron star, which lose the angular momentum by emission of gravitational waves, which then leads to mass transfer from the white dwarf onto the neutron star. The flux of the resulting X-ray emission is modulated at both the orbital period and a long, 170-d, period. We explain the 170-d period via the Kozai mechanism, which is a quasiperiodic tidal effect due to the presence of a 3rd star in the system. We calculate the resulting periodic variability of the inner eccentricity and the mass transfer rate. We have also discovered a strong dependence of the orbital modulation on the X-ray spectral state.

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Pierre Eckert
Office fédéral de météorologie et de climatologie MétéoSuisse

Weather forecasting: from manual work to numerical modelling

Abstract. Weather forecasting has always been a challenge to mankind in order to plan agricultural activities at first. With the invention of telecommunication at the end of the 19th century it became possible to exchange meteorological information in real time and so to get information on the distribution of these parameters on a wide area. Conceptual methods to analyse, develop and transport weather features have then been used for a while. At the same time, the classical hydrological equations (Newton, Euler, Navier-Stokes...) have been simplified and adapted to the atmosphere. With the emergence of computers, these equations could be integrated numerically and used as operational tools. The construction of these numerical models will be discussed in this talk.

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Pascal Favre
Hôpital Neuchâtelois, Service cantonal de radio-oncologie

Radiotherapy, the treatment of cancer with ionizing radiation

Abstract. I will give an overview of the job of a medical physicist in a radio-oncology department of a public Swiss hospital. After a short description of the different types of cancer routinely treated, I will describe the biological effects of ionizing radiation on the tumors, i.e. the radiobiology of the treatments. I will also describe the sources of radiation - in particular the clinical linear accelerator - as well as the means used to deliver a given dose of radiation precisely on a tumor, avoiding the surrounding tissues/organs which are often at risk, i.e. organs in which the dose shall be minimised in order to avoid the loss of its functionality. I will finish with a few perspectives, both in terms of progression of the number of new cases detected each year and in terms of the new advanced techniques designed to respond to this phenomenon.

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Andres Carmona
MPIA Heidelberg, ESO Garching

Studies of the gas in protoplanetary disks

Abstract. Circumstellar disks surrounding low- and intermediate- mass stars in their pre-main sequence phase are the locations where planets presumably form. Such protoplanetary disks are composed of gas and dust. Their mass and dynamics are dominated by gas (99%), specifically by molecular hydrogen (H₂), the most abundant gas species. Observationally, very little is known about the gas compared to the dust. However, if we want to answer major questions in planet formation such as: How massive are the disks?, How extended are the disks?, and How long do the protoplanetary disks last? we require information about the gaseous component of the disk. In particular, we would like to characterize warm gas in the inner disk (R < 50 AU), the region where giant planets form.

In this talk, I will discuss several observational diagnostics that could be used for constraining the properties of the diks's gas in the optical, near and mid-infrared bands that I employed during my PhD thesis. I will present a search for CO 4.7 micron emission in Herbig Ae/Be stars that we conducted with the ISAAC near-infrared spectrograph at ESO-VLT. I will report on an attempt for measuring absorption gas features of Herbig Ae/Be disks in the optical spectra of the close visual companions with the FORS2 optical spectrograph at ESO-VLT. I will discuss the results of a large, sensitive survey for molecular hydrogen emission at 12.28 and 17.03 microns in a sample of nearby Herbig Ae/Be and T Tauri stars using the new high-resolution mid-infrared spectrograph VISIR at ESO-VLT. Finally, I will speak about future research possibilities in this field opened by the advent of new ESO instrumentation (i.e. CRIRES ESO's new near-infrared spectrograph), and new research areas that I would like to develop.

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Carla Baldovin Saavedra
Universita degli Studi di Torino

Nucleosynthesis of ²⁶Al and ⁶⁰Fe in a 25 solar masses star

Abstract. Since before they were actually observed in the interstellar medium, the radioactive isotopes ²⁶Al and ⁶⁰Fe were predicted to be produced in different astrophysical sites, one of them being the presupernova evolution of massive stars.

The nucleosynthesis of both isotopes is studied during the post main sequence evolutionary stage of convective shell carbon burning, following a model of a 25 solar masses star and solar metallicity.

²⁶Al is produced exclusively via ²⁵Mg(p,γ)²⁶Al reaction and its abundance is closely related to the proton density, which depends on temperature through ¹²C(¹²C,p)²³Na reaction. A thermal instability developed in the final phase of the carbon burning stage rises the temperature of the shell and gives extra protons injection, increasing the final ²⁶Al abundance. The effects of nuclear uncertainties were also analysed by different tests, showing that the final abundance of ²⁶Al depends linearly on the uncertainties in the cross sections of the reactions ²⁵Mg(p,γ)²⁶Al and ²⁶Al(β⁺)²⁶Mg.

⁶⁰Fe is produced by a chain of neutron capture reactions starting from ⁵⁶Fe during the first phase of the shell carbon burning when the neutron density is higher than 10¹¹ n cm^-3. The final temperature rising in the shell does not affect the final ⁶⁰Fe abundance, because of its large decay time. The tests performed showed that the final ⁶⁰Fe abundance is linearly dependent on the cross section uncertainties of ⁵⁹Fe(n,γ)⁶⁰Fe, therefore a measure of this cross section is needed.

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Jan Forbrich
Max-Planck-Institut für Radioastronomie & Uni Jena

Coronae in the Coronet - Simultaneous X-ray to radio multi-wavelength observations of a young stellar cluster

Abstract. Multi-wavelength monitoring can provide important information about physical processes in young stellar objects such as the relation between accretion processes and X-ray emission. While coronal processes should mainly cause variations in the X-ray and radio bands, accretion processes may be traced by time-correlated variability in the X-ray and optical/infrared bands. We present the first simultaneous X-ray, radio, near-infrared, and optical multi-wavelength monitoring campaign succeeding in detecting X-ray to radio variability in extremely young objects like class I and class 0 protostars. Our target is the compact Coronet cluster in the Corona Australis star-forming region, harbouring at least one class 0 protostar, several class I objects, numerous T Tauri stars, and a few Herbig AeBe stars. A core sample of seven objects was detected simultaneously in the X-ray, radio, and optical/infrared bands. While most of these sources exhibit clear variability in the X-ray regime and several display also optical/infrared variability, none of them shows significant radio variability on the timescales probed. We also do not find any case of clearly time-correlated optical/infrared and X-ray variability. This suggests that there is no direct link between the X-ray and optical/infrared emission, supporting the notion that accretion is not an important source for the X-ray emission of these YSOs. Combining our Chandra data with previous observations results in one of the most sensitive X-ray observations yet of a star-forming region allowing a virtually complete census of YSOs in the Coronet region.

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George Fraser
Space Research Centre, University of Leicester

The current status of the Lobster imaging X-ray monitor

Abstract.

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J. S. Yadav
Tata Institute of Fundamental Research, Mumbai, India

Origin of superluminal jets in microquasar GRS 1915+105

Abstract. We discuss the origin of superluminal jets in microquasars and provide tight correlation between accretion disk and superluminal jet parameters. We find that the accretion rate during the very high luminosity state (VHS) like the plateau state in GRS 1915+105 is very high and suggest that the accretion disk during the plateaux is always associated with radiation-driven wind. The internal shock forms in the previously generated slowly moving wind (during plateau) with β ≤ 0.01 as the fast moving discrete jet (usually at the end of plateau) with β ~ 1 catches up and interacts with it. The power of superluminal jet is determined by the strength and speed of these two components; the slow moving wind and the fast moving jet which are related to the accretion disk during the plateau state. Finally, we discuss the implications of this work.

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Cédric Foellmi
European Southern Observatory, Chile

Which black-hole is the closest to the Sun: GRO J1655-40 or 1A 0620-00 ?

Abstract. We have found that the distance of the microquasar GRO J1655-40 is build as a house of cards. Pulling it down reveals that it is much closer than previously thought. This new distance not only provides new clues about the origin and the formation of the black-hole, but raises also the question of what is the closest black-hole to the Sun. The previous record was held by 1A 0620-00. I will discuss the distances of GRO J1655-40 and 1A 0620-00, and in particular on what real measurements they are build. I will show that while the new distance of the former is now quite secure, that of the latter is not; and the question of the closest black-hole to the Sun is still open.

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Celine Boehm
CERN, Geneva

Possible origin of low energy positrons in our galaxy

Abstract. The precise determination by INTEGRAL/SPI of the 511 keV emission properties in our galaxy has proven the existence of anti-matter in our galaxy. Its origin is unknown. However, thanks to SPI findings, it is now possible to exclude a great number of astrophysical sources. Shortly after INTEGRAL's announcement it was realized that Dark Matter could be at the origin of the low energy positrons. After summarizing the implication of SPI findings on possible astrophysical sources, I'll explain the Dark Matter model and discuss its implication for astrophysics, cosmology and particle physics.

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Katja Pottschmidt
Center for Astrophysics and Space Sciences (CASS), Univ. of California at San Diego

Understanding Black Hole Binaries: Recent Highlights

Abstract. I briefly review the development of the current picture of black hole states, including recent work using X-ray hardness intensity diagrams to characterize the evolution of outbursts of black hole binaries. Selected results from modeling RXTE and INTEGRAL observations of Cyg X-1, GRS 1758-258, and GX 339-4 will be presented, covering the observation of an unusual state (soft/off state), high time-resolution analyses (Lorentzian decomposition of the power spectrum, time lags), and broad band spectral modeling ("eqpair" models, jet models). The results highlight the importance of monitoring observations at radio and X-ray wavelengths as well as the importance of applying physical accretion models, e.g., models including emission from the jet.

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Daniel Kranich
Institute for Particle Physics, ETH Zürich

Results from the 1st year of data taking with the MAGIC telescope

Abstract. The MAGIC Cherenkov telescope is located on the Canary island La Palma at 2200 m above sea level. The main objective is the investigation of Gamma-ray sources in the energy range from ~50 GeV up to several TeV utilizing an effective collection area in the order of 10⁵ m². Here I present a summary of the MAGIC observations which have been carried out since the end of the commissioning phase in October 2004.

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Volker Beckmann
NASA Goddard Space Flight Center

The Hard X-ray 20-40 keV AGN Luminosity Function

Abstract. We present the first luminosity function of active galactic nuclei (AGN) in the 20-40 keV energy range, based on 70 extragalactic objects detected by the imager IBIS/ISGRI on-board INTEGRAL. It was obtained by compiling a complete, significance limited sample based on ~25,000 square degrees to a limiting flux of 3 10^-11 ergs/cm²/sec (~7,000 square degrees to a flux limit of 10^-11 ergs/cm²/sec) in the 20-40 keV band with INTEGRAL. We have constructed a detailed exposure map to compensate for effects of non-uniform exposure. The flux-number relation is best described by a power-law with a slope of 1.66 ± 0.11. Integration of the cumulative flux per unit area leads to f_x = 2.6 10^-10 ergs/cm²/sec, which is about 1% of the known 20-40 keV X-ray background.

The AGN luminosity function shows a smoothly connected two power-law form, with an index of Γ₁ = 0.9 below, and Γ₂ = 2.2 above the turn-over luminosity of L_x = 4.6 10⁴³ ergs/sec. The emissivity of all INTEGRAL AGNs per unit volume is W(> 10⁴¹ ergs/sec) = 2.8 10³⁸ ergs/sec/Mpc³. These results are consistent with those derived in the 2-20 keV energy band and do not show a significant contribution by Compton-thick objects. Because the sample used in this study is truly local (z = 0.022), only limited conclusions can be drawn for the evolution of AGNs in this energy band. But the objects explaining the peak in the cosmic X-ray background are likely to be either low luminosity AGN (L_x < 10⁴¹ ergs/sec) or of other type, such as intermediate mass black holes, clusters, and star forming regions.

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Giovanni F. Bignami
Centre d'Etude Spatiale des Rayonnements (CESR), Toulouse, France

History in Space

Abstract. The talk will be centered on the recent French edition of my book "Explorer l'espace pour remonter le temps" (Odile Jacob, Paris, 2006). It tells the story of some great Europeans who gave their names to well known scientific space missions of recent years. The missions are: ESA's Giotto, NASA's Galileo, ESA/NASA's Cassini, ASI's BeppoSax, NASA's RossiXTE and ESA's Bepi Colombo. The lives and times of Giotto di Bondone in the 14th century, of Galileo Galilei and Jean-Dominique Cassini in the 17th, and of Giuseppe Occhialini, Bruno Rossi and Giuseppe Colombo in the 20th will be presented, together with science highlights of their namesake missions. Italian, European and US history are presented as a background for the advancement of culture, as reflected in the naming of great space enterprises.

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Yves Etienne
CICR/ICRC Geneva

Integrated ICRC assistance in Pakistan

Abstract. Presentation of the main ICRC (International Committee of the Red Cross) emergency programs in Health, Engineering and Economic Security which are being implemented in emergency in the aftermath of the earthquake which hit Pakistan administrated Jammu & Cashmere on October 8th 2005.

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Michele Maggiore
Geneva University

Gravitational waves and spherical detectors

Abstract. I will give an overview of the motivations and of the present status of the search for gravitational waves. I will then discuss a new project in which our Geneva group is involved, the developement of an advanced spherical resonant-mass detector.

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Andrzej A. Zdziarski
N. Copernicus Astronomical Center, Poland

Spectra and variability of black-hole binaries

Abstract. I will review spectral states and state transitions of black hole binaries and their theoretical accretion and jet models. Of particular interest are luminosities close to the Eddington achieved in the hard (also called low) state, and hysteresis of the transtions. Then I will discuss modelling of variability properties of Cyg X-1 and other black hole binaries, including energy-dependent rms, power spectra, spectral variability patterns and various spectral-timing correlations.

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Ezequiel Treister
University of Chile / Yale

AGN Unification and the X-ray Background

Abstract. The simplest AGN unification paradigm, one in which the ratio of obscured to unobscured AGN is constant with redshift and luminosity, can successfully explain the multiwavelength number counts of the X-ray sources detected in the GOODS fields, that include the deepest Chandra/XMM observations. Assuming a constant ratio of obscured to unobscured AGN of 3:1, including Compton-thick sources, we were able to explain the spectral shape and normalization of the X-ray background. Based on new observations that suggest that the relative number of obscured AGN can decrease with luminosity, we introduce a luminosity dependence in our unification model. This new model can still explain the properties of sources in the GOODS fields and is consistent with the X-ray background observations. The possible dependence of the obscured to unobscured ratio with redshift and ways to test this dependence will be discussed.

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Giorgio G.C. Palumbo
University of Bologna

Jet and accretion-disk emission untangled in 3C 273

Abstract. A long-term spectral variability study of 3C 273 on data obtained by BeppoSAX allows us to decouple the beamed nonthermal (jet) and unbeamed thermal (accretion flow) radiation produced in the inner region of a radio-loud active galactic nucleus. Jet power, when compared with unbeamed radiation, increases with energy. The thermal component is generally overwhelmed by the nonthermal radiation, by a factor of 1.2 to 3 in the 2- to 10-keV range and up to a factor of 7 above 20 keV. In only one case, the accretion flow overcomes the jet, allowing the Kα iron line to emerge clearly over the continuum.

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Dave Willis
Southampton Univ.; MPE, Garching & ISDC, Versoix

Evidence of polarisation in the prompt gamma-ray emission from GRB 930131 and GRB 960924

Abstract. The true nature of the progenitor to Gamma-Ray Bursts (GRBs) remains elusive; one characteristic that would constrain our understanding of the GRB mechanism considerably is gamma-ray polarimetry measurements of the initial burst flux. We present a method that interprets the prompt GRB flux as it Compton scatters off the Earth's atmosphere, based on detailed modelling of both the Earth's atmosphere and the orbiting detectors. The BATSE mission aboard the Compton Gamma-Ray Observatory (CGRO) monitored the whole sky in the 20 keV - 1 MeV energy band continuously from April 1991 until June 2000. We present the BATSE Albedo Polarimetry System (BAPS), and show that GRB 930131 and GRB 960924 provide evidence of polarisation in their prompt flux that is consistent with degrees of polarisation of Π > 35% and Π > 50%, respectively. While the evidence of polarisation is strong, the method is unable to strongly constrain the degree of polarisation beyond a systematics based estimation. Hence the implications on GRB theory are unclear, and further measurements essential.

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Georg Weidenspointner
CESR Toulouse, France

A Mystery of the Galactic Bulge: SPI Observations of Positron Annihilation

Abstract. The imaging spectrometer SPI on board ESA's INTEGRAL observatory provides us with an unprecedented view of positrons in our Galaxy. The first all-sky maps in the 511 keV annihilation line and in the positronium continuum show a puzzling concentration of annihilation radiation in the galactic bulge. The annihilation of positrons appears to be even more concentrated in the bulge than old stellar populations such as Type Ia supernovae, novae, or low-mass X-ray binaries. New, speculative physics like positron production from light dark matter has begun to be discussed as a possible solution. High-resolution spectroscopy of the bulge emission is providing additional clues. SPI allowed us to solve a few of the positron annihilation puzzles of the past, but has deepened the mystery of the galactic bulge.

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Zeljka Bosnjak
SISSA Trieste, Italy

Gamma-ray bursts: clues from the spectra and variability of the prompt phase

Abstract. I will discuss some present hot topics of Gamma Ray Bursts (GRB) related to their association with supernovae (SN), the recently found spectral correlations for long GRBs and the properties of hard GRB spectra. I will present the results of the spectral and temporal analysis of GRB/SN candidates and discuss them in comparison with the large BATSE GRBs population. This analysis seems to point out the possible presence of a significant number of underluminous, GRB 980425-like events whose nature is worth to be investigated. The BATSE bursts also allow to probe the recently found spectral correlations of GRBs. I will present and discuss the recent results which seems to indicate that the BATSE GRB population is cosistent with such spectral correlations. Finally I will consider a newly found hard burst which could be interpreted in the framework of the standard model as representative of the transition between the photospheric to the internal shock dominated phase.

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Michel Tagger
Service d'Astrophysique, CEA Saclay, France

Accretion-Ejection Instability, QPOs and a Magnetic Flood model for the variability of microquasars

Abstract. The Accretion-Ejection Instability occurs in magnetized accretion disks, in the configuration used for MHD models of jets. We have shown that it is a good candidate to explain the low-frequency Quasi-Periodic Oscillation (QPO) of microquasars. I will present the physics of this instability, which produces a spiral wave and a Rossby vortex in the inner region of the disk. I will then show how, by comparing the physics of the instability and the observed properties of GRS 1915+105 during its 30 minutes cycles, one can elaborate a scenario where these cycles, and more genrally the variability of this source, could be explained by the cycling of poloidal magnetic flux in the disk. If time permits, I will also briefly discuss a possible mechanism for the high-frequency QPO of microquasar.

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Peggy Varnière
Rochester University, NY, USA

Disk Instabilities in X-ray Binaries

Abstract. Accretion disks exist on a wide variety of mass scales, from Young Stellar Objects (YSO) to Active Galactic Nuclei (AGN). These objects are also known to emit jets, therefore linking accretion to ejection. X-ray binaries offer a unique opportunity to tackle the problem through the Quasi-Periodic Oscillation (QPO) observed in the X-ray spectrums of such objects. I will present some analytical and numerical studies of accretion disk instabilties and how they can be related to observations.

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Volker Beckmann
NASA Goddard Space Flight Center & Joint Center of Astrophysics, University of Maryland, Baltimore County

Swift and the perspectives in the gamma-ray range

Abstract. Swift has been launched successfully in November 2004. First preliminar results will be shown, such as BAT images and spectra as well as a first XRT image. This includes images of the Cygnus region, Swift/BAT spectra of the Crab, early results from GRBs, and XRT observations of Cas A. I will give an outlook on the Swift mission and its implications on the astrophysical research in the gamma-ray region, and especially which effects Swift might have on the research done by INTEGRAL. In addition I will show some of the activities which are performed by the INTEGRAL Guest Observer Facility at NASA's Goddard Space Flight Center.

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Elena V. Seifina
Sternberg Astronomical Institute, Moscow

Analysis of the `local minima'-effect detected in multifrequency observations of SS 433

Abstract. In the available observational data obtained with the INTEGRAL gamma-ray observatory (March - May 2003) and the X-ray satellites GINGA (1986 - 1991), ASCA (1993 - 1996) and RXTE (1996-2004), as well as in the optical observations with the 0.6 m telescope of the SAI Crimean observatory in the Johnson V-filter (1979 - 2000), stable repeatable local minima have been discovered at certain orbital and precessional phases, apart from the regular primary and secondary minima of the orbital light curve. This discovery does not fit into the commonly adopted model of the SS 433 binary system. The empirical rule of this specific feature arising in the light curve was established. We analyzed this `local minima'-effect in the frame of the colliding wind model taking into account the accretion disk wind asymmetry and derive the values of the physical parameters of the model. We conclude that an additional obscuring component of the system should be taken into account when calculating the light curve at elongate phases (φ = 0.25, 0.75) near the disk face-on configuration of SS 433.

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Pavel Ivanov
Queen Mary College (London) & Astro Space Centre of Lebedev Physics Institute (Moscow)

The tidal disruption of stars by a supermassive binary black hole

Abstract. In this talk I would like to consider the problem of tidal disruption of stars in the centre of a galaxy containing a supermassive binary black hole with non-equal masses. I show that the bulk of the stars with a small value of the angular momentum projection on the axis perpendicular to the binary orbital plane can obtain a small absolute value of the angular momentum during the secular evolution in the gravitational field of the binary, and hence these stars can be tidally disrupted by the larger black hole residing in the centre of the stellar distribution. This effect is analogous to the so-called Kozai effect well known in celestial mechanics. I also discuss an analytical theory of the secular evolution of the stellar orbits in the gravitational field of the binary and of the stellar cluster, estimate the rate of tidal disruption and confront it with a simple numerical model.

It is shown that when the larger black hole has a mass >10⁷M_Sun, the mass ratio of the two black holes is > 10^-2, and the size of the inner part of the stellar cluster where the gravitational field of the central black hole is dominant is of the order of ~ 1 pc, the tidal disruption rate can be as large as ~1 M_Sun/yr. This is at least 10⁴ times larger than it was estimated for the tidal disruption rate in the centre of a galaxy containing a single supermassive black hole.

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Jianfeng Zhou
Center for Astrophysics, Tsinghua University, China

The Hard X-ray Modulation Telescope

Abstract. The Hard X-ray Modulation Telescope (HXMT) is a collimated hard X-ray (20-200 keV) telescope with high sensitivity and spatial resolution. It will perform an all-sky hard X-ray survey, in which about 1000 new hard X-ray sources would probably be discovered, as well as sensitive pointed observations of important cosmic X-ray sources including black holes and neutron stars.

HXMT is based on the direct demodulation (DD) method and the well developed NaI(Ti)/CsI(Na) phoswich detecting techniques. The Phase A study of the HXMT mission has been jointly supported by the Ministry of Science and Technology of China, the Chinese Academy of Sciences, and Tsinghua University since 2000. So far, all the key technical difficulties of the telescope have been overcome, the ground prototype of HXMT has been constructed, and the balloon borne flight testing has been finished. The platform HXMT will use is that of ``Ziyuan II'' (Earth Resource II) satellite series. This long-time tested platform meets the requirements of HXMT very well, and there is no key technical difficulty that needs to be surmounted. Therefore, HXMT is ready for development and launch.

Finally, I also would like to say something about the future data center for HXMT.

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Jian-Min Wang
Tübingen University, Germany

Witnessing blob ejection from the vicinity of the black hole in MCG-6-30-15

Abstract.

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Robert Laing
European Southern Observatory (Garching, Germany)

Kinematics and dynamics of relativistic jets

Abstract. The end-on relativistic jets that produce spectacular gamma-ray emission energies must have side-on counterparts. For nearby BL Lac objects, including the known TeV sources, these counterparts are low-luminosity (FR I) radio galaxies. Their jets are bright at radio wavelengths, and also often show optical and X-ray synchrotron emission. The jets must decelerate from relativistic (>0.9c) to sub-relativistic (<0.1c) speeds on kiloparsec scales. Modelling of deep, high-resolution VLA images of the jets in FR I radio galaxies on kiloparsec scales has allowed us to derive their three-dimensional distributions of velocity, emissivity and magnetic-field structure, all for the first time. We have demonstrated that deceleration, transverse velocity gradients and the dominance of the toroidal field component on large scales are general features of FR I jets. By combining our models of jet kinematics with measurements of the external pressure and density derived from Chandra observations, we can also derive the jet dynamics via a conservation-law approach. This gives us the variation of pressure, density, entrainment rate and Mach number along the jets, again for the first time. We can also quantify the amount and location of distributed particle acceleration independently from radio and X-ray observations.

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Robert Laing
European Southern Observatory (Garching, Germany)

The Atacama Large Millimetre Array (ALMA)

Abstract. ALMA is an array of 64 12 m antennas currently under construction under a bilateral agreement between Europe and North America on the Chajnantor Plateau in Chile at an altitude of 5 km. It is an aperture-synthesis array optimised for millimetre and sub-millimetre wavelengths, for which the site has excellent transmission. There are 250 antenna locations, so the array can be configured to sample a range of spatial scales up to a maximum resolution of 0.005 arcsec. Total-power operation is also possible. When complete in 2012, it will be the premier instrument for millimetre and sub-millimetre astronomy. It is designed to cover all frequency bands accessible from the ground between 31 and 950 GHz with excellent sensitivity. In operation, it will be integrated with the Japanese ALMA Compact Array (ACA) project, which provides four 12m and twelve 7m antennas, optimised for observations of large spatial scales.

This talk will outline the most important scientific and technical challenges facing the ALMA project and will describe recent progress.

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Simona Soldi
IASF/CNR, Milano & ISDC, Geneva

Propriétés multifréquences des noyaux galactiques actifs dans le domaine gamma et perspectives pour AGILE

Abstract. Le satellite AGILE, une mission de l'Agence Spaciale Italienne (ASI) qui sera lancée dans la seconde moitié de 2005, sera sensible dans le domaine des rayons gamma entre 10 et 40 keV et entre 30 MeV et 30 GeV. Un des principaux objectifs scientifiques sera l'observation de l'émission gamma par les blazars, une sous-classe des noyaux actifs de galaxies (AGN) dont l'émission dans le domaine 30 MeV-30 GeV a déjà été observée par l'instrument EGRET à bord de Compton-GRO.

Nous avons compilé un catalogue qui recueille les informations multifréquences pour les AGNs d'EGRET et nous avons comparé les caractéristiques de ces objets avec celles d'un ensemble d'AGNs radio. Parmi les résultats obtenus par cette étude, il y a la sélection d'une liste des possibles AGNs radio candidats à l'observation par AGILE. Nous avons estimé qu'AGILE pourra révéler environ 5-10 AGNs pour chaque pointage.

Nous avons étudié la variabilité des AGNs gamma et sa relation avec les autres caractéristiques de ces objets. Aucune différence claire n'a été montrée par la comparaison entre les propriétés des blazars d'EGRET et celles des AGNs radio sélectionnés comme possibles candidats à l'émission gamma.

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Felix Aharonian
Max-Planck-Institut für Kernphysik (Heidelberg, Germany)

On the links between hard X-rays and very high energy gamma-rays from different galactic and extragalactic source populations

Abstract. It is well recognized that within the inverse-Compton models of very high energy gamma-rays of objects like supernova remnants, plerions, blazars, etc., one should expect strong synchrotron X-radiation produced by the same population of (directly accelerated) multi-TeV electrons. I will show that strong TeV/X-ray correlations are expected also in hadronic models of TeV gamma-ray emission, the X-rays being result of synchrotron radiation of secondary electrons produced either at decays of charged pions or due to internal absorption of gamma-rays at interactions with ambient photon fields. Because of very short cooling time of these electrons (compared to the typical dynamical timescales), the pi°-decay gamma-rays are accompanied, almost simultaneously, with hard X-rays. In many cases the synchrotron X-ray emission of "hadronic" origin could extend to 100 keV or even beyond. I will demonstrate the importance of this effect for shell type SNRs, AGN and clusters of galaxies, and suggest an observational strategy for search for cosmic PeVatrons with the INTEGRAL mission.

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Vladimir N. Lukash
Astro Space Centre of Lebedev Physics Institute (Moscow)

The Universe: cosmological model in the beginning of the XXI century

Abstract. We discuss the progress and problems of modern cosmological model: initial conditions, inflation constraints, coincidence of Large Scale Structures (LSS) and Cosmic Microwave Background (CMB) scales, observational status, dark matter and dark energy, cosmological parameters and degeneracies between them, minimal model, its extensions and problems.

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Masahiro Tsujimoto
Pennsylvania State University

Gamma-ray and X-ray observations of YSOs in nearby star-forming regions

Abstract. With the launch of the Chandra X-ray Observatory, the X-ray studies of young stellar objects (YSOs) and star formation has shown a rapid progress, with its unprecedented spatial resolution and hard X-ray sensitivity. I will present new insights that we obtained in the last 3 years from our two deep-exposure Chandra studies of Orion Molecular Clouds 2 and 3 and the rho Ophiuchi dark cloud, including X-ray detections from protostars and brown dwarfs. X-ray diagnosis on forming stars is also discussed. Although emission above 10 keV is routinely observed from the Sun, it has not been yet detected from any objects in star-forming clouds. I also discuss the detectability of the gamma-ray emission from these youngest objects and what we can learn from it.

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Didier Besset
Sogeti, Switzerland

eXtreme Programming, a Quick Introduction

Abstract. eXtreme Programming (XP) is a methodology for software developments that originated in the states about 5 years ago. Originally born among Smalltalkers, it has gained wide acceptance among Java developers in the recent years. Unlike other methodology such as RUP, XP is not a product that can be bought in a box or from a series of consultants. eXtreme Programming is foremost a philosophy, which is transmitted to a whole team of developers in order to increase its efficiency.

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Maria Catarina
LIP, Portugal

EUSO Operations: flight & ground

Abstract. The Extreme Universe Space Observatory (EUSO) has the main goal of studying the extreme energy cosmic rays, observing the dark atmosphere of Earth from space. EUSO has recently finished its ESA Phase A study and is planned for accomodation in 2009 on the International Space Station (ISS). In this talk the EUSO mission is introduced. The planning of the EUSO operations and ground segment are discussed in further detail. Both the on-board and the on-ground system play an important role in operations. The fulfilment of the scientific goals of the mission and the safety of the instrument require the defintion of different operational modes and procedures. Since no permanent contact with the payload is provided, a considerably autonomy of the on-board system is required. The EUSO Science Operations and Data Centre (SODC) will constitute the EUSO scientific ground segment. It shall ensure the scientific mission control and planning and address the issues of data collection, monitoring, distribution and archiving.

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Roberto Trotta
Cosmology Group, Geneva University

CMB vs. BBN-guided Helium measurement: an emerging tension?

Abstract. Standard Big Bang Nucleosynthesis (BBN) predicts the abundance of the light elements as a function of one free parameter, namely the baryon density. Cosmic microwave background (CMB) anisotropies probe with high accuracy the baryon content of the universe. Combination of CMB-determined baryon density, astrophysical measurements of the light element abundances and standard BBN calculations is a powerful tool to constrain non-standard physics in the early universe.

I review the standard BBN predictions for the light elements as derived using the baryon abundance determined by WMAP and discuss discrepancies with current astrophysical measurements. As the most abundant among the light elements (about 25% in mass), I focus on ⁴He and I present the first determination of the Helium mass fraction (Yp) using CMB data alone, 0.16 < Yp < 0.50 (at 68% cl). I identify degeneracies with other cosmological parameters and show that the uncertainity in the Helium mass fraction will have to be taken into account in order to correctly recover the baryon abundance from Planck-quality data.

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Andrii Neronov
Theoretical Physics, Univ. de Lausanne

Particle acceleration near black holes in galactic nuclei, microquasars and gamma-ray bursts

Abstract. I consider a mechanism of extraction of rotational energy of a black hole in which strong electric field generated by the black hole rotation leads to production of large amount of high-energy particles in the vicinity of the horizon. Maximal energies of particles are limited by the synchrotron/curvature energy loss. In this synchrotron loss dominated regime the acceleration process is accompanied by strong gamma-ray emission from the acceleration volume. I argue that operation of the high energy particle accelerators in the vicinity of the black hole horizon can power the activity of low-luminosity AGNs, microquasars and gamma-ray bursts.

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Gopal Krishna
National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune, India

Intra-night optical variability of different classes of powerful AGN

Abstract. Intra-night monitoring of the optical flux has been carried out for a matched sample of 4 different classes of luminous quasars, consisting of radio-quiet and radio-loud quasars (including blazars). The campaign needed 112 nights of observations spread over 4 years. Intranight variations above 1% level were detected for all the four AGN classes, allowing their variability characteristics to be compared for the first time and to develop a possible common theoretical framework for the phenomenon.

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Ingo Kreykenbohm
IAA Tübingen, Germany

The variable Cyclotron Line in GX 301-2

Abstract. We present observations of the High Mass X-ray Binary GX 301-2 taken in 2000 November with the Rossi X-ray Timing Explorer. The neutron star orbits its companion, the B1 Ia+ hyper giant Wray 977, in an eccentric 41.5 day orbit. During periastron passage the neutron star passes through the outer atmosphere in a height of ~0.1 R_star above Wray 977, resulting in strong X-ray flaring activity.

We observed the system for ~200 ksec during the pre-periastron flare and the actual periastron passage of the neutron star. To model the spectrum we use a power law with the Fermi Dirac cutoff and a cyclotron line at higher energies plus either a reflection component or a heavily absorbed partial covering component. Phase resolved spectra show that the energy and the depth of the cyclotron resonant scattering feature vary strongly with pulse phase: It is deepest in the rise of the secondary pulse, while it is relatively weak in the rise of the main pulse. The energy varies by more than 25% from ~29 keV to ~39 keV.

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Juri Poutanen
University of Oulu, Finland

On the Nature of the X-ray Emission from Accreting Millisecond Pulsars

Abstract. We study the pulse profiles of the accreting X-ray millisecond pulsar SAX J1808.4-3658 at different energies. The observed variability can be explained if the emission is produced by Comptonization in a hot slab (radiative shock) of Thomson optical depth 0.3-1 at the neutron star surface. The emission patterns of the black body and the Comptonized radiation are different: a ``pencil"- and a ``fan"-like, respectively. We construct a detailed model of the X-ray production accounting for the Doppler boosting, relativistic aberration and gravitational light bending in the Schwarzschild spacetime. Our model reproduces well the pulse profiles at different energies simultaneously, corresponding phase lags, as well as the time- averaged spectrum. We constrain the compact star mass to be bounded between 1.2 and 1.6 solar masses. The radius is determined to be 8.5+/-0.5 km or 10.8+/-0.7 km for a 1.4 or 1.6 solar mass neutron star, respectively. This puts strong constraints on the neutron star equation of state.

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Yaël Fuchs
CEA Saclay

Microquasar Jets

From Binary Systems to the Inter-Stellar Medium

Abstract. Microquasars, the miniature replicas of distant quasars and radio-galaxies, are far from unveiling their mysteries. Although tiny and weak compared to quasars, their sizes and distances are advantageous when observing these X-ray binaries producing jets. Thus, studying microquasars can help us to understand the complex physical phenomena of accretion and ejection of material surrounding a compact object. This review on microquasars will focus on the properties of the jets at small and large scales, touching on the analogy with quasars. I will also present the MINE collaboration and its attempts to conduct multi-wavelength observations simultaneously with INTEGRAL.

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Rober Preece
University of Alabama

A Gamma-Ray Burst Monitor for GLAST

Abstract.

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Alexei Pozanenko
Space Research Institute Moscow

Simultaneous optical and X-ray observations of GRBs

Abstract. We consider simultaneous X-ray, Gamma-ray and optical observations of cosmic gamma-ray bursts. Based on available observations we discuss criteria for the development of a wide field camera and present the automatic telescope that is being developed for the purpose of simultaneous optical observations of GRB counterparts.

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Mike Revnivtsev
MPA, Garching & IKI, Moscow

Super-Eddington outburst in a binary system: V4641 Sgr

Abstract. X-ray transients provide an unique opportunity to probe accretion regimes at vastly different accretion rates. I present the results of one of the most enigmatic transient source - the high mass X-ray binary V4641 Sgr - and argue that its giant September 1999 outburst was associated with an episode of super-Eddington accretion onto the black hole. During the outburst an extended optically thick envelope/outflow has been formed around the source making the observational appearance of V4641 Sgr in many aspects very similar to that of SS433.

These results suggest that objects like V4641 Sgr and SS433 indeed represent the class of objects accreting matter at a rate comparable or above Eddington value and the formation of an envelope/outflow is a generic characteristic of supercritical accretion. When the accretion rate decreased the envelope vanished and the source short term variability and spectral properties started to resemble those of other galactic black hole candidates accreting at a rate well below the Eddington value.

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Jérôme Rodriguez
ISDC, Geneva & CEA, Saclay

Spectro-temporal Studies of Microquasars in X-rays

Abstract. Microquasars are binary systems in our Galaxy composed of a normal star and a stellar mass black hole (or a neutron star). Their name comes from the fact that the compact object ejects matter in powerful jets similar to those observed in distant quasars. This talk will be dedicated to the study of three microquasars, hosting a black hole, mainly through the spectral and temporal properties of their soft (1-10 keV) and hard (10-100 keV) X-ray emissions.

I will first briefly define and present the useful terms and the basic physics underlying the phenomena occurring in the close vicinity of these objects from both the spectral and temporal point of view. I will then turn to the study of two microquasars, GRO J1655-40 and GRS 1915+105 and present the link between quasi-periodic oscillations (QPO) and spectral parameters. I show how the spectro-temporal behavior of both sources, although different, are in good agreement with the theoretical predictions of the Accretion-Ejection Instability (AEI).

A third object, XTE J1550-564, will be then studied over a period of outbursts. I will point out the presence of two different X-ray emitting media, which relative geometry may be changing through the outburst. I will also present the evolution of low frequency QPOs and compare it to the theoretical predictions of some models of these features.

As a conclusion, I will discuss all these results in the framework of theoretical models compatible with the observations presented along this talk.

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Akiko Kawachi
University of Tokyo, Japan

The CANGAROO Project

TeV gamma-ray observations by ground-based telescopes in Australia

Abstract. CANGAROO (the Collaboration of Australia and Nippon (Japan) for a GAmma Ray Observatory in the Outback) project has been exploring the southern sky in the sub-TeV to multi-TeV energy range using the ground-based Cherenkov telescopes located in South Australia. Supernova remnants of non-thermal X-ray detection, rotation-powered pulsars of large dE/dt over d² value, and other galactic unique objects including our Galactic Center have been selected as observation targets, together with some nearby X-ray selected BL Lacs and (starburst) galaxies. Introduction of the project and some recent results will be presented.

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Giorgio Palumbo
University of Bologna, Italy

A view from the window, birth and growth of X-Ray Astronomy

Abstract. A history and evolution of X-ray astronomy presented on the occasion of the Nobel Prize 2002, which was awarded to Riccardo Giacconi.

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Luigi Foschini
IASF-CNR Bologna

Search for Ultra-luminous X-ray Sources in Nearby Galaxies

Abstract. Little is presently known about the nature of ultraluminous X-ray sources (ULX). Different hypotheses have been proposed to explain their properties: intermediate-mass black holes, Kerr black holes, young supernova remnants (SNR), or background active galactic nuclei (AGN). Some of the current problems and open questions in this research field are here reviewed.

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Vladimir N. Lukash
Astro Space Center, Moscow

Qualitative Breakthrough in Observational Cosmology

Abstract. We present the results of a direct reconstruction of the cosmological model from recent observational data on large scale structure and cosmic microwave background anisotropy.

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Simon Shaw
ISDC, Geneva

Imaging the Gamma Ray Sky with BATSE

Abstract. The Burst and Transient Source Experiment (BATSE) was one of the instruments on board the Compton Gamma Ray Observaotory (CGRO), which operated in a low Earth orbit for ~ 9 years from 1991 - 2000. BATSE was designed with a 4$\pi$ field of view with the primary aim of detecting as many gamma ray bursts as possible above 20 keV. More persisitent sources of gamma rays can be observed using the Earth Occultation Technique where images of the Earth's limb, caused by gamma ray sources rising above or setting below the horizon, can be projected on to the sky to build up an image. To fully use the long 9 year exposure of BATSE it is necessary to produce an accurate background model. The BATSE Mass Model uses a Monte Carlo technique, based on the INTEGRAL Mass Model (TIMM) produced at Southampton, and is capable of accurately reproducing the observed background in all of the 16 BATSE energy channels every 2 seconds for the entire mission. The background modelling and imaging techniques have allowed the production of the first all sky images in the 20 - 100 keV band to be seen since the HEAO-1 A4 mission of 1978-79. When all the data is considered the final survey should have a sensitivity of ~ 1 mCrab and angular resolution < 1 degree.

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J.-L. Atteia
LAOMP, Obs. Midi-Pyrénée

Two years of GRB observation with HETE/FREGATE

Abstract. HETE-2 has been launched in October 2000. During its first two years of operation it successfully detected and localized a few tens GRBs. I will present the main results of the mission, with an emphasis on the gamma-ray instrument (called FREGATE) and on observations which may be of direct interest for the INTEGRAL GRB hunters.

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B.J. Teegarden
LHEA at NASA/GSFC

Overview of activities at the Goddard Space Flight Center in support of SPI

Abstract.

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Ken Ebisawa
ISDC, NASA/GSFC

Chandra Deep X-ray Observation of the Galactic Plane

Abstract. Using the Chandra X-ray satellite, we have carried out the deepest X-ray observation on a typical Galactic plane region. Our main motivations were

1. to examine if the Galactic plane hard X-ray emission is truly diffuse emission or composed of numerous point sources, and
2. to investigate the nature of the dimmest X-ray sources on the Galactic plane.

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V.N. Lukash
Lebedev Physical Institute, Moscow

Cosmological Parameters from LSS and CMB observations

Abstract. The parameters of the cosmological model are constrained from the observational data on large scale structure in the Universe (LSS): spatial and redshift distributions of galaxy clusters, Lyman-alpha systems, bulk peculiar velocities, CMB anisotropy. The relation to other data and stability of the result are discussed.

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J. Farine
Carleton University, Canada

Measurement of charged current interactions produced by ⁸B solar neutrinos at the Sudbury Neutrino Observatory

Abstract. Solar neutrinos from the decay of ⁸B have been detected at the Sudbury Neutrino Observatory (SNO) via the charged current (CC) reaction on deuterium and by the elastic scattering (ES) of electrons.
The CC reaction is sensitive exclusively to nu_e's, while the ES reaction also has a small sensitivity to nu_mu's and nu_tau's. The flux of nu_e's from ⁸B decay measured by the CC reaction rate is
phi^CC(nu_e) = 1.75+-0.07(stat.)+0.12-0.11(syt.)+-0.05(theor) x 10⁶ cm^-2s^-1.
Assuming no flavor transformation, the flux inferred from the ES reaction rate is
phi^ES(nu_x) = 2.39+-0.34(stat.)+0.16-0.14(sys.) x 10⁶ cm^-2s^-1.

Comparison of phi^CC(nu_e) to the Super-Kamiokande Collaboration's precision value of phiES(nu_x) yields a 3.3 sigma difference, providing evidence that there is a non-electron flavor active neutrino component in the solar flux. The total flux of active ⁸B neutrinos is thus determined to be 5.44+-0.99 x 10⁶ cm^-2s^-1, in close agreement with the predictions of solar models.

The data selection and analysis procedures leading to the first SNO results will be presented. The future plans will then be outlined.

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Fabio Favata
ESA

Eddington: a stellar structure and planet-finding explorer

Abstract. The Eddington mission (an element of the "Horizons 2000" plan of the European Space Agency) has two primary scientific goals: to produce the data on stellar oscillations necessary to understand stellar structure and evolution and to detect and characterize habitable planets around other stars. These goals will be achieved through very sensitive continuous photometric monitoring of a very large number of stars, with a precision that can only be achieved from space.

I will discuss Eddington's science case, as well as present its baseline payload and implementation. Also, I will discuss the programmatic aspects (current plans for its implementation, current activities, etc.).

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Patrick Nédélec
LAPP Annecy-le-Vieux

EUSO, an observatory for Ultra High Energy Cosmic Rays

Abstract. The EUSO experiment is looking for extremly high energy cosmic rays by studying showers developping in the atmosphere, using a telescope installed on the International Space Station. The detection technique is based on the fluorescence emission of Nitrogen and on the Cherenkov light. The large EUSO field of view covers a 500 km diameter area. This permits to significantly increase the statistics of cosmic rays events above 5x10¹⁹ eV, where the GZK cut-off is expected. EUSO is also capable to detect ultra high energy neutrinos, in a way similar to the charged particles. It could also look for lower energy neutrinos (~10¹⁴ eV) corresponding to tau neutrinos crossing the earth.

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Martin Pohl
CERN

AMS, A Particle Physics Experiment in Space

Abstract. The Alpha Magnetic Spectrometer, AMS, is a detector for charged and neutral particles, compact and light enough to be transported on a space craft. Its main physics goals are to detect antinuclei of cosmic origin in near Earth orbit, measure the composition and spectra of charged cosmic rays and photons up to TeV energies, and to search for dark matter signals.

After a successful pilot mission of a first version of the detector on NASA space shuttle Discovery in 1999, a more ambitious second version of the detector, AMS-02, is now being built. It is scheduled for installation on the International Space Station in October 2003, for a data taking period of at least three years. I will present the particle physics program of the AMS-02 project, review the expected performance of the detector and comment of the status of its construction.

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Pierre Le Coultre
CERN

Astroparticle Physics with the L3+C detector at CERN

Abstract. A short description of the L3+C detector at LEP, CERN, is given, as well as the techniques we develop to search for particular burst signals (possible GRB signals, high energy solar flare signals). The composition of the primary cosmic rays in the knee region, the muon momentum spectrum as well as other topics related to cosmic rays and elementary particle physics are also under study.

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Andrei Bykov
St. Petersburg

A model for nonthermal emission from clusters of galaxies

Abstract. We present detailed kinetic modeling of nonthermal electron injection, acceleration and propagation in a virialized cluster of galaxies and find that the cluster halos are efficient electron accelerators and sources of extended hard X-ray and gamma-ray emission. The energy spectrum of the electrons is shaped by the joint action of first and second order Fermi acceleration at MHD shock fronts in a turbulent plasma with substantial Coulomb losses. Inverse-Compton, bremsstrahlung and synchrotron radiation by these electrons produce spectra that are in quantitative agreement with the hard X-ray and radio emission observed from the Coma cluster. We discuss also the nonthermal emission from large scale accretion shocks in clusters.

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Gustav Tammann
University of Basel

Supernovae rates and distances

Abstract.

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Volker Beckmann
Hamburger Sternwarte

Evolutionary behaviour of BL Lac objects

Abstract. The Hamburg RASS X-ray bright BL Lac sample (HRX-BL Lac) consists of 106 X-ray selected objects, with 77 BL Lacs forming a complete sample. The candidates have been selected from a cross-correlation of the ROSAT All-Sky Survey with the NVSS radio catalogue. This selection results in an X-ray dominated sample of high frequency cut-off BL Lac objects. The large number of objects allows detailed studies of the dependencies of physical parameters on the spectral energy distribution. The complete sample is used to study the evolution of the different subtypes of BL Lac objects.

A scenario, in which BL Lacs start as luminous low frequency cut-off objects and then fade to the state of high frequency cut-off, is proposed on the basis of the different evolutionary behaviour and on the different observed quantities.

Within the course of identification also a possible ultra-high frequency cut-off BL Lac has been found, which could be the counterpart of an up to now unidentified EGRET source. This object could be a promising target for an INTEGRAL observation.

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Evanthia Hatziminaoglou
Laboratoire d'Astrophysique de Toulouse

Quasars: Cosmic Laboratories and Cosmological Probes

Abstract. Our understanding of the nature of AGN physics implies events of a dramatic importance. Nowadays, the idea that the source that nourishes the AGN is accretion onto a super massive black hole seems to satisfy the majority of the people working in this field. If this idea is realistic, their principle properties depend upon very "exotic" physics. The modeling of the accretion disk implies plasma physics, their X-ray and gamma-ray emission invokes high-energy physics and all the above has to be put together with a lot of patience, humor and imagination.

AGN optical and UV spectra indicate the state of the accretion disk and the matter distribution in space via the Lyman forest, their X-ray spectra give hints about the structure of the accretion disk, infrared observations provide information about the dusty material around them and simultaneous multi-wavelength observations of these objects can cast light on dark points such as the unification scheme or the variability.

Apart from being interesting objects as individual entities, quasars also offer the opportunity of assembling relatively large and unbiased samples of "standard candles" since their statistical properties do not seem to depend on the redshift. Once their luminosity function modeled, geometrical cosmological tests such as the V/Vmax can be applied in order to define the values of the cosmological parameters. Furthermore, their contribution to the overall UV, X-ray and gamma-ray background can be estimated, as well as their role in the reionization history of the Universe.

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Martin Burgdorf
Space Science Department of ESA, ISO Data Center, Madrid

ISO Observations of Mars

Abstract. Infrared spectra of Mars were taken in July and August 1997 with the LWS (Long Wavelength Spectrometer) and the SWS (Short Wavelength Spectrometer) onboard the European Space Agency's Infrared Space Observatory, ISO. They covered the wavelength range from 2.3 to 45 micron with a spectral resolution of about 1500 and from 45 to 180 micron with a resolution between 150 and 300. In addition, scans of selected H₂O lines have been recorded in Fabry-Perot mode, where the spectral resolution is more than an order of magnitude higher.

A multitude of water lines was detected, and their strengths were determined by means of Interactive Analysis tools. Comparisons of the measured lines in the near-infrared with various synthetic spectra allowed us to obtain information about the vertical distribution of water vapor. Assuming atmospheric and surface temperatures derived from the European Martian Climate Database with a slight adjustment to the observed 15 micron CO2 band, the ISO data indicate an H₂O water distribution confined in the lower atmosphere, within the first 11-15 km above the surface, and a total column density of 12 ppt-micron.

Once the water vertical distribution was determined, the mean surface emissivity remained as the most important unknown in the model spectra for the far infrared and could therefore be derived from the measured line to continuum ratios in the LWS range. It was found to have an average value of 0.95 +- 0.03 and to be slightly decreasing between 50 and 180 micron.

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Rob Preece
University of Alabama

The BATSE Spectral Analysis Software and its Application to Recent GRB Spectroscopy Results

Abstract. The BATSE gamma-ray burst spectroscopy team has developed a spectral fitting software package optimized for high-energy astrophysics applications. The package, called WINGSPAN (for WINdowing Gamma-ray SPectral ANalysis), operates in a standard windowing environment on time-sequences of spectra stored in the portable FITS format. Separate windows display the temporal rate history and corresponding energy spectrum and allow convenient interactive visual selection of all background, source, temporal and energy ranges. WINGSPAN also uses a highly efficient fitting engine that has been optimized to operate in both the Gaussian and Poisson statistical regimes. Besides being able to rapidly fit large numbers of spectra in sequence, WINGSPAN is able to jointly fit time-resolved spectra from many different detectors and/or instruments.

Recent results obtained using WINGSPAN will be described, including the BATSE Spectroscopy Catalog and several investigations comparing the observations with predictions of the synchrotron shock model for gamma ray bursts.

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Katja Pottschmidt
Tuebingen

Monitoring Cygnus X-1 with RXTE

Abstract. I present more than two years of RXTE monitoring observations of Cyg X-1 with emphasis on the evolution of the short-term variability (power spectral densities, time lags, coherence functions). Even though Cyg X-1 is the best studied stellar black hole candidate and the prime example for displaying the canonical black hole hard statem a detailed monitoring of this state has obly become possible with RXTE. Correlations of spectral and temporal parameters in this state as well as correlated behavior at radio wavelengths will be shown and discussed in the light of different accretion models.

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Stéphane Paltani
ISDC, Geneva

30 years of multi-wavelength observations of the quasar 3C 273

Abstract.

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Frédéric Daigne
MPA, Garching

Gamma-ray bursts from internal shocks in a relativistic wind

Abstract.

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