Letter to the Editor

Simultaneous multi-wavelength observations of GRS 1915+105^*,**,***

¹ Service d'Astrophysique (CNRS FRE 2591), CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
² Integral Science Data Center, Chemin d'Ecogia, 16, 1290 Versoix, Switzerland
³ Instituto de Astonomía y Física del Espacio / CONICET, cc67, suc 28, 1428 Buenos Aires, Argentina
⁴ Université Paris 7, Fédération APC, 2 place Jussieu, 75005 Paris, France
⁵ National Radio Astronomy Observatory, Socorro, NM 87801, USA
⁶ Mullard Radio Astronomy Observatory, Cavendish Laboratory, Madingley Road, Cambridge CB3 0HE, UK
⁷ N. Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw, Poland
⁸ Observatory, PO Box 14, 00014 University of Helsinki, Finland
⁹ Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse, 85748 Garching, Germany
¹⁰ Danish Space Research Institute, Juliane Maries Vej 30, 2100 Copenhagen Oe, Denmark

Corresponding author: Y. Fuchs, yfuchs@cea.fr

Received: 4 August 2003
Accepted: 1 September 2003

Abstract

We present the result of multi-wavelength observations of the microquasar GRS 1915+105 in a plateau state with a luminosity of  erg s^-1 (~40% ), conducted simultaneously with the INTEGRAL and RXTE satellites, the ESO/NTT, the Ryle Telescope, the NRAO VLA and VLBA, in 2003 April 2–3. For the first time were observed concurrently in GRS 1915+105 all of the following properties: a strong steady optically thick radio emission corresponding to a powerful compact jet resolved with the VLBA, bright near-IR emission, a strong QPO at 2.5 Hz in the X-rays and a power law dominated spectrum without any cutoff in the 3–400 keV range.