30 years of multi-wavelength observations of 3C 273^*

¹ Geneva Observatory, Ch. des Maillettes 51, CH-1290 Sauverny, Switzerland
² INTEGRAL Science Data Centre, Ch. d'Écogia 16, CH-1290 Versoix, Switzerland
³ University of Michigan, Department of Astronomy, 817 Dennison Building, Ann Arbor, MI 48 109, U.S.A.
⁴ European Southern Observatory, Casilla 19 001, Santiago 19, Chile
⁵ Cerro Tololo Inter-American Observatory, Casilla 603 – La Serena, Chile
⁶ Tuorla Observatory, Väisäläntie 20, FIN-21 500 Piikkiö, Finland
⁷ Department of Physics, University of Southampton, Southampton SO9 5NH, UK
⁸ Centre for Astrophysics, University of Central Lancashire, Preston, PR1 2HE, UK
⁹ Joint Astronomy Centre, 660 North A`oh$\bar{\mbox{o}}$k$\bar{\mbox{u}}$ Place, University Park, Hilo, Hawaii 96 720, U.S.A.
¹⁰ Mullard Space Science Laboratory, University College London, Holmbury St. Mary, Dorking, Surrey RH5 6NT, UK
¹¹ Metsähovi Radio Observatory, Metsähovintie, FIN-02 540 Kylmälä, Finland
¹² European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85 748 Garching bei München, Germany
¹³ Remote Sensing Division, Naval Research Laboratory, Washington, DC 20 375-5351, U.S.A.
¹⁴ ESA-Vilspa, P.O. Box 50 727, E-28 080 Madrid, Spain
¹⁵ Department of Astronomy, University of California, Berkeley, CA 94 720, U.S.A.

Send offprint request to: M. Türler (ISDC)

Received: 23 June 1998
Accepted: 23 July 1998

Abstract

We present a wide multi-wavelength database of most observations of the quasar 3C 273 obtained during the last 30 years. This database is the most complete set of observations available for an active galactic nucleus (AGN). It contains nearly 20 000 observations grouped together into 70 light curves covering 16 orders of magnitude in frequency from the radio to the γ-ray domain. The database is constituted of many previously unpublished observations and of most publicly available data gathered in the literature and on the World Wide Web (WWW). It is complete to the best of our knowledge, except in the optical (UBV) domain where we chose not to add all observations from the literature. In addition to the photometric data, we present the spectra of 3C 273 obtained by the International Ultraviolet Explorer (IUE) satellite. In the X-ray domain, we used the spectral fit parameters from the literature to construct the light curves. Apart from describing the data, we show the most representative light curves and the average spectrum of 3C 273. The database is available on the WWW in a homogeneous and clear form and we wish to update it regularly by adding new observations.