Speaker:  Zhongli Zhang (Makishima Lab, University of Tokyo)

Time:   November 20th, 2:00pm

Location:  3rd floor, Middle Conference Room

Abstract:  Dipping low-mass X-ray binaries (LMXBs) are expected to be essentially the same compared to non-dipping LMXBs, except for their more edge-on inclinations. This provides us an opportunity to probe the dependence of the LMXB emission on the viewing angles, by comparing the persistent X-ray spectra of dippers and non-dippers. To accomplish this scientific goal, the Suzaku observatory is the most suited based on its superior spectral resolution and hard X-ray band coverage. We took the first step of the 39 ks Suzaku observation of the dipping source XB 1916-053 on November 8th, 2006. We focused on its non-dip non-burst period, and derived an unabsorbed luminosity of ~4E36 erg/s in 2 -- 20 keV. We found that its 0.8 -- 45 keV broad-band spectrum can be described by the canonical model of Mitsuda+84 for the soft-state LMXBwith stronger Comptonization. The corona electron temperature is above 10 keV. This indicates possible existence of extra hot coronae closely above the accretion disk.