your ID: 0276 First Name: XiaoLing Last Name: Zhang Affiliation: MPE Title: GRO J1655-40 from ASCA and XMM-Newton observations Authors: Xiao-Ling Zhang, Shuangnan Zhang, Gloria Sala, Jochen Greiner, Yuxin Feng, Yangsen Yao Topic: 2 Session: oral Abstract: We analyzed the X-ray spectra of the micro-quasar GRO J1655-40, obtained with 4 ASCA observations during the 1996-1997 outburst and 3 XMM-Newton observations during the 2005 outburst. In all these observations the source is in high/soft state, in which the radiation comes mostly from the disk, and the spectra are free or very lightly affected by other components such as hot corona or jet. We modeled the continuum spectra with both multi-color disk model and relativistic disk model, estimated the inner disk radius of the disk, the color correction factor and the spin of the central black hole. The color correction factor changes from observation to observation, and the central black hole is maximally spinning.