3C 273's Database

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.

Introduction
Overview of the database
About the database tables
Radio observations
Millimetre and submillimetre observations
Infrared observations
Optical observations
NTT/EMMI optical spectrum
Ultraviolet observations
Integrated UV emission-line light curves
X-ray and gamma-ray observations
Our related publications on 3C 273
Related links

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

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) F_ν and (b) ν·F_ν 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 F_var 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 [ (F_ν - <F_ν>) / <F_ν> ] (Left); as well as the dispersion-normalized variations [ (F_ν - <F_ν>) / σ_ν ] (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.	Light curve	Date range	# Obs.
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.	Light curve	Date range	# Obs.
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.	Light curve	Date range	# Obs.
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.	Light curve	Date range	# Obs.
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.	Light curve	Date range	# Obs.
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
C IV (total)	blue wing		line core	red wing

X-ray and Gamma-ray observations

Light curve	Date range	# Obs.	Light curve	Date range	# Obs.
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