Supergiant X-ray binaries observed by Suzaku

Date

2012-03-29

Department

Program

Citation of Original Publication

Bodaghee, A., J. A. Tomsick, J. Rodriguez, S. Chaty, K. Pottschmidt, R. Walter, and P. Romano. “Supergiant X-Ray Binaries Observed by Suzaku.” AIP Conference Proceedings 1427, no. 1 (March 29, 2012): 52–55. https://doi.org/10.1063/1.3696150.

Rights

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Bodaghee, A., J. A. Tomsick, J. Rodriguez, S. Chaty, K. Pottschmidt, R. Walter, and P. Romano. “Supergiant X-Ray Binaries Observed by Suzaku.” AIP Conference Proceedings 1427, no. 1 (March 29, 2012): 52–55. https://doi.org/10.1063/1.3696150. and may be found at https://doi.org/10.1063/1.3696150.

Subjects

Abstract

Suzaku observations are presented for the high-mass X-ray binaries IGR J16207−5129 and IGR J17391−3021. For IGR J16207−5129, we provide the first X-ray broadband (0.5–60 keV) spectrum from which we confirm a large intrinsic column density (NH = 1.6 ×10²³ cm⁻² ), and we constrain the cutoff energy for the first time (Ecut = 19 keV). A prolonged (> 30 ks) attenuation of the X-ray flux was observed which we tentatively attribute to an eclipse of the probable neutron star by its massive companion, in a binary system with an orbital period between 4 and 9 days, and inclination angles > 50 degrees. For IGR J17391−3021, we witnessed a transition from quiescence to a low-activity phase punctuated by weak flares whose peak luminosities in the 0.5–10 keV band are only a factor of 5 times that of the pre-flare emission. These micro flares are accompanied by an increase in NH which suggests the accretion of obscuring clumps of wind. We now recognize that these low-activity epochs constitute the most common emission phase for this system, and perhaps in other supergiant fast X-ray transients (SFXTs) as well. We close with an overview of our upcoming program in which Suzaku will provide the first ever observation of an SFXT (IGR J16479−4514) during a binary orbit enabling us to probe the accretion wind at every phase.