SUZAKUBROADBAND SPECTROSCOPY OFSWIFTJ1753.5–0127 IN THE LOW-HARD STATE

Mark T. Reynolds, Jon M. Miller, Jeroen Homan, Giovanni Miniutti
2009 Astrophysical Journal  
We present Suzaku observations of the Galactic black hole candidate Swift J1753.5-0127 in the low-hard state. The broadband coverage of Suzaku enables us to detect the source over the energy range 0.6 -- 250 keV. The broadband spectrum (2 -- 250 keV) is found to be consistent with a simple power-law (gamma ∼ 1.63). In agreement with previous observations of this system, a significant excess of soft X-ray flux is detected consistent with the presence of a cool accretion disc. Estimates of the
more » ... c inner radius infer a value consistent with the ISCO (R_in≲ 6 R_g, for certain values of, e.g. N_H, i), although we cannot conclusively rule out the presence of an accretion disc truncated at larger radii (R_in∼ 10 - 50 R_g). A weak, relativistically-broadened iron line is also detected, in addition to disc reflection at higher energy. However, the iron-K line profile favours an inner radius larger than the ISCO (R _in∼ 10 - 20 R_g). The implications of these observations for models of the accretion flow in the low-hard state are discussed.
doi:10.1088/0004-637x/709/1/358 fatcat:eorzi6osnna2hb3vn4w3flclxm