Simultaneous multi-wavelength observations of GRS 1915+105

Abstract

We present the result of multi-wavelength observations of the microquasar GRS 1915+105 in a plateau state with a luminosity of ∼7.5 × 1038 erg s-1 (∼40% LEdd), 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.