0620021

GRS 1915+105 can be considered as the prototype microquasar. It does in short times what other sources do over several days or more. We hence can catch these variations very easily with pointing INTEGRAL and thus have a unique chance to understand their physical origin through a broad band (spectral and temporal) study of the source. Placed in a multiwavelength context this will permit us to understand the tight connections that exist between the different emitting media. Understanding this source will help us understand all microquasars. After very successful results obtained in the past AOs we propose to continue the monitoring of GRS 1915+105 and its surroundings during AO6. We plan to (quasi-)simultaneously observe the source in the broadest waveband ever achieved from radio (Ryle GBT) to gamma-ray (GLAST) with special emphasis in the X-ray domain (INTEGRAL and possibly RXTE). We require 20 ks INTEGRAL pointings taken every second revolution in order to understand the origin of the high variability of GRS 1915+105 at X-ray energies. These coupled to observations at other wavelengths will permit us to probe the physical mechanisms at work in this source: the connections between accretion and ejection processes the emission processes at high energy the origin of the X-ray spectral transitions and that of the variabilities. The latter two points will be based on the co-use of JEM-X in the soft X-rays and IBIS in the hard X/Gamma-rays and on a simultaneous approach with RXTE. We aim at studying the interplay between the soft and hard X-ray components the different time scales of their variations in relation with different physical models. For the study of the accretion-ejection mechanisms we will provide simultaneous radio (Ryle GBT) and infrared (ESO) observations while the very high energy (with GLAST) will allow us to discriminates among different radiationprocesses and thus different mode [truncated! Please see actual data for full text]