3C 273 's Database

This site gives access to most world wide observations of the quasar 3C 273 covering more than 40 years of measurements from the radio band to gamma-rays.


Contents


Figure 1. Time versus frequency coverage of all observations in the database with colors coding the observed flux intensity in ν·Fν.

Introduction

The bright quasar 3C 273 is one of the best studied active galactic nuclei (AGN) in all spectral bands. The aim of this site is to provide a consistent and as complete as possible database of observations to study the long-term variability of the source across the electromagnetic spectrum. This database provides a series of about 70 lightcurves (i.e. the flux evolution with time) as well as some spectra. In particular, all the International Ultraviolet Explorer (IUE) spectra, from which continuum and emission-line lightcurves have been extracted are also available here.

This site was created in 1998 in parallel to the publication of:

30 years of multi-wavelength observations of 3C 273
Türler M., Paltani S., Courvoisier T.J.-L., et al., 1999, A&AS, 134, 89

A complete update of the database including the data up to 2007 with particular emphasis on the X-ray observations and on variability properties have been published in:

The multiwavelength variability of 3C 273
Soldi S., Türler M., Paltani S., et al., 2008, A&A, 486, 411

These publications give details on the data provided here, so if you use data from this database, please cite these articles. Thank you!

Overview of the database


Figure 2. The average spectral energy distribution of 3C 273 in (a) Fν and (b) ν·Fν representation. The error bars show the observed dispersion σ of the data in each lightcurve. The contribution of the elliptical (E4) host galaxy is suggested by the blue line, whereas the green line shows approximately the contribution from the outer jet according to Conway et al. (1993) for the radio domain and to Marshall et al. (2001) for the optical and X-ray parts.

Figure 3. The variability properties of 3C 273 illustrated (a) by the range of maximum-to-minimum observed flux deviations (grey area) together with the average SED as in Fig. 2 and (b) by the fractional variability amplitude Fvar calculated using only good observations in the best observed lightcurves and excluding optical and infrared data with significant contribution from synchrotron flares (i.e. only Flag=0 data).

The table of lightcurve properties summarizes the values used in Figures 2 & 3.
NB: less reliable data (Flag<0) and CGRO/BATSE measurements have not been considered here.

Figure 4. Same as Figure 1 but with the logarithmic color scale representing the relative variations [ (Fν - <Fν>) / <Fν> ] (Left); as well as the dispersion-normalized variations [ (Fν - <Fν>) / σν ] (Right).

About the database tables

The tables below give access to the lightcurve plots and to the actual data in one ASCII table per light curve. The light curves are characterized by the date range between the first and the last observation and the number of observations # Obs.. The quoted decimal Year is a linear function of the Julian Date (JD) defined as: Year = 2000.0 + (JD-2'451'544.5)/365.25.

A quality Flag column was introduced to allow an easy selection of the data. Good data have a Flag of 0 or 1, where Flag=1 is being used for optical and infrared observations with significant contribution from synchrotron flares. Less reliable data have a negative Flag. Flag=-1 for "useless" data in the sense that they do not add useful information; Flag=-2 for "uncertain" data usually having large error bars; and Flag=-3 for "dubious" data that are outstanding compared to other observations. The litterature Reference is given for each data point in a coded manner using the initials of the three first authors and the year of publication. The code correspondence for the complete list of references is given in the Reference list.

In the lightcurve plots, good data (Flag>=0) are shown in black or in red, whereas "useless", "uncertain" or "dubious" (Flag<0) data points are shown in grey. The red color is used for highlighting synchrotron flares in the optical and infrared range (Flag=1).


Radio observations

Light curve Date range # Obs. Plot Light curve Date range # Obs. Plot
0.02 GHz 1975-1975 5 0.04 GHz 1965-1966 2
0.1 GHz 1962-1981 4 0.2 GHz 1963-1985 8
0.4 GHz 1962-1981 17 0.8 GHz 1963-1975 11
1.5 GHz 1962-2004 15 2.5 GHz 1964-1995 2960
5 GHz 1967-2006 923 8 GHz 1963-2006 1588
10 GHz 1965-1995 3389 15 GHz 1963-2006 1295
22 GHz 1976-2004 1108 37 GHz 1970-2006 1276

Millimetre and submillimetre observations

Light curve Date range # Obs. Plot Light curve Date range # Obs. Plot
3.3 mm 1965-2006 1574 2 mm 1981-2004 204
1.3 mm 1981-2007 545 1.1 mm 1973-2007 322
0.8 mm 1981-2007 496 0.45 mm 1982-1996 79
0.35 mm 1983-1995 17        

Infrared observations

Light curve Date range # Obs. Plot Light curve Date range # Obs. Plot
200 μm 1982-1996 5 100 μm 1982-1996 7
60 μm 1983-1996 4 Q (20 μm) 1971-2004 18
N (10 μm) 1970-2004 79 M (4.8 μm) 1983-1993 40
L (3.6 μm) 1969-2004 183 K (2.2 μm) 1967-2004 360
H (1.65 μm) 1967-2004 323 J (1.25 μm) 1976-2004 286

Optical observations

Light curve Date range # Obs. Plot Light curve Date range # Obs. Plot
I (9000 Å) 1982-2002 134 R (7000 Å) 1977-2002 188
G (5798 Å) 1985-2003 446 V (5479 Å) 1968-2005 745
V1 (5395 Å) 1985-2003 446 B2 (4466 Å) 1985-2003 446
B (4213 Å) 1968-2005 766 B1 (4003 Å) 1985-2003 446
U (3439 Å) 1968-2005 697        

NTT/EMMI optical spectrum


This NTT/EMMI spectrum of 3C 273 (electronic data, eps figure) was taken on 19 June 2004 at La Silla, Chile as part of the multi-wavelength campaign reported in:
A historic jet-emission minimum reveals hidden spectral features in 3C 273
Türler M., Chernyakova M., Courvoisier T. J.-L., et al., 2006, A&A 451, L1-L4

Ultraviolet observations

The lightcurves below have been extracted from the IUE spectra taken between 1978 and 1996. To download spectra in ASCII format, click the following button:

Light curve Date range # Obs. Plot Light curve Date range # Obs. Plot
3000 Å 1978-2005 220 2700 Å 1978-1996 212
2425 Å 1978-2005 219 2100 Å 1978-2005 219
1950 Å 1978-1996 256 1700 Å 1978-1996 256
1525 Å 1978-1996 256 1300 Å 1978-1996 256
1050 Å 1990-1996 3        

Integrated UV emission-line light curves

Below are the Lyα and C IV emission-line light curves defined and studied in:
Dynamics of the Lyα and C IV emitting gas in 3C 273 ADS Abstract
Paltani S. & Türler M., 2003, ApJ 583, 659-669
Lyα (total) blue wing line core red wing
far blue wing near blue wing near red wing far red wing
IV (total) blue wing line core red wing

X-ray and Gamma-ray observations

Light curve Date range # Obs. Plot Light curve Date range # Obs. Plot
0.1 keV 1979-1995 22 0.2 keV 1979-1993 20
0.5 keV 1969-2005 62 1 keV 1969-2005 73
2 keV 1969-2005 97 5 keV 1969-2005 1036
10 keV 1969-2005 1029 20 keV 1976-2005 4328
50 keV 1977-2005 4343 100 keV 1978-2005 4342
200 keV 1978-2005 3382 500 keV 1990-1999 15
1 MeV 1990-1999 20 3 MeV 1991-1999 9
10 MeV 1993-1999 8 30 MeV 1991-1999 17
100 MeV 1976-1997 28 300 MeV 1976-1997 16
1 GeV 1991-1997 15 3 GeV 1991-1997 15
10 GeV 1991-1997 14        

List of X-ray and gamma-ray spectral fit parameters


Our related publications on 3C 273

2003-2005 INTEGRAL and XMM-Newton observations of 3C 273
Chernyakova M., Neronov A., Courvoisier T. J.-L., et al., 2007, A&A 465, 147-156
A historic jet-emission minimum reveals hidden spectral features in 3C 273
Türler M., Chernyakova M., Courvoisier T. J.-L., et al., 2006, A&A 451, L1-L4
Simultaneous observations of the quasar 3C 273 with INTEGRAL and RXTE
Courvoisier T. J.-L., Beckmann V., Bourban G., et al., 2003, A&A 411, L343-L348
The mass of the black hole in 3C 273
Paltani S. & Türler M., 2005, A&A 435, 811-820
Dynamics of the Lyα and C IV emitting gas in 3C 273
Paltani S. & Türler M., 2003, ApJ 583, 659-669
Modelling 20 years of synchrotron flaring in the jet of 3C 273
Türler M., Courvoisier T.J.-L., Paltani S., 2000, A&A 361, 850-862
Modelling the submillimetre-to-radio flaring behaviour of 3C 273
Türler M., Courvoisier T.J.-L., Paltani S., 1999, A&A 349, 45-54
The blue-bump of 3C 273
Paltani S., Courvoisier T.J.-L., Walter R., 1998, A&A, 340, 47-61
The bright quasar 3C 273
Courvoisier T.J.-L., 1998, A&A Rev., 9, 1-32

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Last modified: 14 June 2013
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