D. R. Ballantyne, J. D. Purvis, R. G. Strausbaugh, R. C. Hickox
X-ray reflection signatures are observed around multiple classes of accreting
compact objects. Modelling these features yield important constraints on the
physics of accretion disks, motivating the development of X-ray reflection
models appropriate for a variety of systems and illumination conditions. Here,
constant density ionized X-ray reflection models are presented for a disk
irradiated with a very hard power-law X-ray spectrum (\Gamma < 1) and a
variable high-energy cutoff. These models are then applied to the Suzaku data
of the accreting X-ray pulsar LMC X-4, where very good fits are obtained with a
highly ionized reflector responsible for both the broad Fe K line and the soft
excess. The ionized reflector shows strong evidence for significant Doppler
broadening and is redshifted by ~10^4 km/s. These features indicate that the
reflecting material is associated with the complex dynamics occurring at the
inner region of the magnetically-truncated accretion disk. Thus, reflection
studies of X-ray pulsar spectra may give important insights into the accretion
physics at the magnetospheric radius.
View original:
http://arxiv.org/abs/1202.2311
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