Letter to the Editor
Science Data Centre, Chemin d'Écogia 16, 1290 Versoix, Switzerland
2 Geneva Observatory, Chemin des Maillettes 51, 1290 Sauverny, Switzerland
3 Institut für Astronomie und Astrophysik, Universität Tübingen, Sand 1, 72076 Tübingen, Germany
4 Danish Space Research Institute, Juliane Maries Vej 30, 2100 Copenhagen Ø, Denmark
5 Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA
6 Department of Physics and Astronomy, University of Leicester, University road, Leicester LE1 7RH, UK
7 N. Copernicus Astronomical Ctr, Bartycka 18, 00716 Warsaw, Poland
Corresponding author: T. Courvoisier (ISDC), Thierry.Courvoisier@obs.unige.ch
Accepted: 1 August 2003
INTEGRAL has observed the bright quasar 3C 273 on 3 epochs in January 2003 as one of the first observations of the open programme. The observation on January 5 was simultaneous with RXTE and XMM-Newton observations. We present here a first analysis of the continuum emission as observed by these 3 satellites in the band from 3 keV to 500 keV. The continuum spectral energy distribution of 3C 273 was observed to be weak and steep in the high energies during this campaign. We present the actual status of the cross calibrations between the instruments on the three platforms using the calibrations available in June 2003.
Key words: gamma-rays: observations / galaxies: active / quasars: general / quasars: individual: 3C 273
Based on observations with INTEGRAL, an ESA project with instruments and science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, Spain), Czech Republic and Poland, and with the participation of Russia and the USA.
© ESO, 2003