Title:	Supergiant fast X-ray transients versus classical supergiant high mass X-ray binaries: Does the difference lie in the companion wind?
Authors:	Pradhan, Pragati Bozzo, E. Paul, Biswajit
Keywords:	X-rays binaries
Issue Date:	Feb-2018
Publisher:	EDP Sciences for European Southern Observatory
Citation:	Astronomy & Astrophysics, 2018, Vol.610, A50
Abstract:	We present a comparative study of stellar winds in classical supergiant high mass X-ray binaries (SgXBs) and supergiant fast X-ray transients (SFXTs) based on the analysis of publicly available out-of-eclipse observations performed with Suzaku and XMM-Newton. Our data set includes 55 observations of classical SgXBs and 21 observations of SFXTs. We found that classical SgXBs are characterized by a systematically higher absorption and luminosity compared to the SFXTs, confirming the results of previous works in the literature. Additionally, we show that the equivalent width of the fluorescence Kα iron line in the classical SgXBs is significantly larger than that of the SFXTs (outside X-ray eclipses). Based on our current understanding of the physics of accretion in these systems, we conclude that the most likely explanation of these differences is ascribed to the presence of mechanisms inhibiting accretion most of the time in SFXTs, thereby leading to a much less efficient photoionization of the stellar wind compared to classical SgXBs. We do not find evidence for the previously reported anticorrelation between the equivalent width of the fluorescence iron line and the luminosity of SgXBs.
Description:	Open Access
URI:	http://hdl.handle.net/2289/6919
ISSN:	0004-6361 1432-0746 (Online)
Alternative Location:	http://adsabs.harvard.edu/abs/2018A%26A...610A..50P https://arxiv.org/abs/1711.10510 https://doi.org/10.1051/0004-6361/201731487
Copyright:	2018 European Southern Observatory
Appears in Collections:	Research Papers (A&A)

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