Jun, 2016
SUZAKU OBSERVATION OF THE HIGH-INCLINATION BINARY EXO 0748-676 IN THE HARD STATE
ASTROPHYSICAL JOURNAL
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- Volume
- 823
- Number
- 2
- First page
- 131
- Last page
- Language
- English
- Publishing type
- Research paper (scientific journal)
- DOI
- 10.3847/0004-637X/823/2/131
- Publisher
- IOP PUBLISHING LTD
Utilizing archived Suzaku data acquired on 2007 December 25 for 46 ks, the X-ray spectroscopic properties of the dipping and eclipsing low-mass X-ray binary EXO 0748-676 were studied. At an assumed distance of 7.1 kpc, the data provided a persistent unabsorbed luminosity of 3.4 x 10(36) erg cm(-2) s(-1) in 0.6-55 keV. The source was in a relatively bright low/hard state, wherein the 0.6-55 keV spectrum can be successfully explained by a "double-seed" Comptonization model incorporating a common corona with an electron temperature of similar to 13 keV. The seed photons are thought to be supplied from both the neutron star surface and a cooler truncated disk. Compared to a sample of non-dipping, low-mass X-ray binaries in the low/hard state, the spectrum is subject to stronger Comptonization with a relatively larger Comptonizing y-parameter of similar to 1.4 and a larger coronal optical depth of similar to 5. This result, when attributed to the high inclination of EXO 0748-676, suggests that the Comptonizing corona may elongate along the disk plane and provide a longer path for the seed photons when viewed from edge-on inclinations.
- Link information
- ID information
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- DOI : 10.3847/0004-637X/823/2/131
- ISSN : 0004-637X
- eISSN : 1538-4357
- Web of Science ID : WOS:000377410000062