Astronomy and Astrophysics – Astrophysics – High Energy Astrophysical Phenomena
Scientific paper
2010-04-14
Astronomy and Astrophysics
Astrophysics
High Energy Astrophysical Phenomena
12 pages, 11 figures, accepted for publication in ApJ
Scientific paper
In this paper we present a comprehensive survey of 41 X-ray binaries (10 HMXBs and 31 LMXBs) with Chandra, with specific emphasis on the Fe K region and the narrow Fe Kalpha line, at the highest resolution possible. We find that: a) The Fe Kalpha line is always centered at 1.9387 +- 0.0016 Angstroms, compatible with Fe I up to Fe X; we detect no shifts to higher ionization states nor any difference between HMXBs and LMXBs. b) The line is very narrow, with FWHM < 5 mAngstroms, which means that the reprocessing material is not rotating at high speeds. c) Fe Kalpha fluorescence is present in all the HMXB in the survey while such emissions are very rare (~ 10% ) among LMXBs. d) The lack of Fe line emission is always accompanied by the lack of any detectable K edge. e) We obtain the empirical curve of growth of the equivalent width of the Fe Kalpha line versus the density column of the reprocessing material, i.e. EW_{Kalpha} vs N_{H}, and show that it is consistent with a reprocessing region spherically distributed around the compact object. f) We show that fluorescence in X-ray binaries follows the X-ray Baldwin effect. We interpret this finding as evidence of decreasing neutral Fe abundance with increasing X-ray illumination and use it to explain some spectral states of Cyg X-1 and as a possible cause of the lack of narrow Fe line emission in LMXBs. g) Finally, we study anomalous morphologies. We present the first evidence of a Compton shoulder in the HMXB X1908+075. Also the Fe Kalpha lines of 4U1700-37 and LMC X-4 present asymmetric wings suggesting the presence of highly structured stellar winds in these systems.
Kallman Tim R.
Nowak Maciej A.
Schulz Norbert S.
Torrejon Jose Miguel
No associations
LandOfFree
A Chandra survey of fluorescence Fe lines in X-ray Binaries at high resolution does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A Chandra survey of fluorescence Fe lines in X-ray Binaries at high resolution, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Chandra survey of fluorescence Fe lines in X-ray Binaries at high resolution will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-525668