4U 1957+11: A POSSIBLE BLACK HOLE ACCRETION DISK CORONA SOURCE

We propose XMMNewton observations of the persistent lowmass Xray binary 4U1957+11. This source, which probably contains a black hole primary, is viewed ata high inclination, which allows for a detailed study of the accretion flow. Ouraim is to study the geometry and properties of the accretion disk and itsextended corona, both on small and large scales, by means of emission andabsorption line features. Moreover, combined with simultaneous RXTE observations (which we have been awarded) we will study the broad band spectrum andvariability in great detail and put stringent constraints on the presence of aneutron star in this system. Finally, we will search for large scale jets likethose recently found in 4U 175533, a source very similar to 4U 1957+11. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]