Barnard, R.; Shaw Greening, L.; Tonkin, C.; Kolb, U. and Osborne, J. P.
|DOI (Digital Object Identifier) Link:||http://dx.doi.org/10.1017/S174392130600809X|
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We have conducted a survey of X-ray sources in XMM-Newton observations of M31, examining their power density spectra (PDS) and spectral energy distributions (SEDs). Our automated source detection yielded 535 good X-ray sources; to date, we have studied 225 of them. In particular, we examined the PDS because low mass X-ray binaries (LMXBs) exhibit two distinctive types of PDS. At low accretion rates, the PDS is characterised by a broken power law, with the spectral index changing from ∼0 to ∼1 at some frequency in the range ∼0.01-1 Hz; we refer to such PDS as Type A. At higher accretion rates, the PDS is described by a simple power law; we call these PDS Type B. Of the 225 sources studied to date, 75 exhibit Type A variability, and are almost certainly LMXBs, while 6 show Type B but not Type A, and are likely LMXBs. Of these 81 candidate LMXBs, 71 are newly identified in this survey; furthermore, they are mostly found near the centre of M31. Furthermore, most of the X-ray population in the disc are associated with the spiral arms, making them likely high mass X-ray binaries (HMXBs). In general these HMXBs do not exhibit Type A variability, while many central X-ray sources (LMXBs) in the same luminosity range do. Hence the PDS may distinguish between LMXBs and HMXBs in this luminosity range.
|Item Type:||Conference Item|
|Extra Information:||Some of the symbols may not have transferred correctly into this bibliographic record and/or abstract.|
|Academic Unit/Department:||Science > Physical Sciences
|Interdisciplinary Research Centre:||Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)|
|Depositing User:||Christopher Biggs|
|Date Deposited:||18 Dec 2006|
|Last Modified:||14 Jan 2016 16:18|
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