Observations of the High-mass X-Ray Binary A 0535+26 in Quiescence
Abstract
We have analyzed three observations of the high-mass X-ray binary A 0535+26 performed by the Rossi X-Ray Timing Explorer (RXTE) three, five, and six months after the last outburst in 2011 February. We detect pulsations only in the second observation. The 3-20 keV spectra can be fit equally well with either an absorbed power law or absorbed thermal bremsstrahlung model. Reanalysis of two earlier RXTE observations made 4 yr after the 1994 outburst, original BeppoSAX observations 2 yr later, reanalysis of four EXOSAT observations made 2 yr after the last 1984 outburst, and a recent XMM-Newton observation in 2012 reveal a stacked, quiescent flux level decreasing from ~2 to <1 × 10^(–11) erg cm^(–2) s^(–1) over 6.5 yr after outburst. The detection of pulsations during half of the quiescent observations would imply that accretion onto the magnetic poles of the neutron star continues despite the fact that the circumstellar disk may no longer be present. The accretion could come from material built up at the corotation radius or from an isotropic stellar wind.
Additional Information
© 2013 American Astronomical Society. Received 2013 January 10; accepted 2013 April 23; published 2013 May 20. We acknowledge the assistance and mentoring of Eric Michelsen concerning Lomb–Scargle analysis and its interpretation, along with use of his program. Thanks go out to Ron Remillard for supplying the weekly A 0535+26 ASM data for the duration of the RXTE mission. These results were provided by the ASM/RXTE teams at MIT and at the RXTE SOF and GOF at NASA's GSFC. We thank Evan Smith for his excellent efforts in scheduling the RXTE observations. We thank ISSI for hosting and financing international group meetings on modeling and observations of cyclotron lines in high-mass X-ray binaries. We acknowledge the GSFC HEASARC for providing extracted spectra and response files for the EXOSAT observations that allowed for the reanalysis of the A0535+26 observations. This work was supported by the Bundesministerium für Wirtschaft und Technologie through DLR grant 50 OR1113. We thank J. E. Davis for the slxfig module which was used to create some of the plots through out this paper. A.C.A. acknowledges the support from grants AYA2012-39303, SGR2009-811, and iLINK2011-0303.Attached Files
Published - 0004-637X_770_1_19.pdf
Submitted - 1304.7283v1.pdf
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Additional details
- Eprint ID
- 39536
- Resolver ID
- CaltechAUTHORS:20130723-133844520
- 50 OR1113
- Bundesministerium für Wirtschaft und Technologie
- AYA2012-39303
- Ministerio de Economía y Competitividad (MINECO)
- SGR2009-811
- Ramon y Cajal programme
- Created
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2013-07-23Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field