0320020

Given the already high scientific return of our INTEGRAL observations of GRS 1915+105 we propose to continue the monitoring of one of the most enigmatic microquasars (and its surroundings with special emphasis on the poorly kown X-ray source IGR J19140+0951) during AO 3. Most of the past observations were done during the plateau state of GRS 1915+105. Our main goal is to obtain time-resolved hard X-ray spectra of all the fundamental spectral states of GRS 1915+105 in order to understand the origin of its high variability and probe the hierarchical evolution between classes with long uninterrupted X-/Gamma -ray observations.The simultaneous use of JEM-X (and RXTE/PCA) in the softer X-rays IBIS and SPI in the hard X-/Gamma-rays will enable us to test different models: Comptonization by thermal nonthermal or free-fall electrons and/or synchrotron emission from the compact jet and test their possible relation with a given class of variability. In addition we are in position to provide simultaneous radio and infrared observations which will allow us to study the accretion-ejection links further. JEM-X will allow us to discriminate between spectral states in the course of each observation and study with the long exposure time the very low frequency QPOs (<10 mHz). As for the past campaign the INTEGRAL observations will be conducted simultaneously with RXTE in order to explore the rapid variability (0.1-100 Hz) at both low and high energies. We will use all our observations to test the presence of (or put tight constraints on) any annihilation features with SPI. To achieve our goals and especially obtain spectra up to very high energy we need long exposure times. We request that our observations be undertaken in segments of 100 ksec exposures. To meet our scientific goals we require ten such segments each separated by 2-3 weeks compatible with scheduling constraints. [truncated! Please see actual data for full text]