Hard X-ray Emission From Low Mass X-ray Binaries

Details Hard X-ray Emission From Low Mass X-ray Binaries Hard X-ray Emission From Low Mass X-ray Binaries

1999-11-03

arxiv.org/abs/astro-ph/9911042v1

Astronomy and Astrophysics

Astrophysics

Accepted for publication in the Astrophysical Journal, 2-column preprint prepared with AAS Latex macros V5.0, 32 pages, 13 fig

Scientific paper

10.1086/308651

We report on Rossi X-ray Timing Explorer observations of four type I X-ray bursters; namely 1E1724-3045, GS1826-238, SLX1735-269 and KS1731-260. The first three were in a low state (LS) whereas KS1731-260 was in a high state. The LS sources have very similar power spectra, displaying high frequency noise up to \~200 Hz. For KS1731-260, its power spectrum is dominated by noise at frequencies below 20 Hz. In addition a quasi-periodic oscillation at 1200 Hz is detected. The 1-200 keV LS spectra are all consistent with resulting from thermal Comptonization with an electron temperature (kTe) around 25-30 keV. For KS1731-260, the spectrum is also dominated by Comptonization, but with kTe around 3 keV and no significant hard X-ray emission. With the exception of GS1826-238, there is an underlying soft component. For all sources, we have detected an iron line at 6.4 keV. A reflection component is present in the spectra of GS1826-238 and SLX1735-269. We suggest a model in which the region of main energy release, where hard X-rays are produced would be an optically thin boundary layer merged with an Advection Dominated Accretion Flow (ADAF). The soft component observed probably represents the unscattered emission from the accretion disk of variable inner radius. When the accretion rate increases, the inner disk radius shrinks, the strength of the reflected component and associated iron line increase, and the Comptonization region cools off in response to an increased cooling flux from the accretion disk and from the reprocessed/reflected component. Finally, in the light of these observations, we discuss extensively the various criteria recently proposed to distinguish between non-quiescent accreting black holes and neutron stars.

Affiliated with

Also associated with

No associations

Rating

Hard X-ray Emission From Low Mass X-ray Binaries 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 Hard X-ray Emission From Low Mass X-ray Binaries, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hard X-ray Emission From Low Mass X-ray Binaries will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-553897