Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS Cyg

Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS Cyg

The X-ray spectrum of SS Cyg in outburst has a very soft component that can be interpreted as the fast-rotating optically thick boundary layer on the white dwarf surface. This component was carefully investigated by Mauche (2004) using the Chandra LETG spectrum of this object in outburst. The spectr...

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Main Authors: V. F. Suleimanov, C. W. Mauche, R. Ya. Zhuchkov, K. Werner
Format: Article
Language:English
Published: CTU Central Library 2015-02-01
Series:Acta Polytechnica CTU Proceedings
Online Access:https://ojs.cvut.cz/ojs/index.php/APP/article/view/2866
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spelling doaj-7ca4938385564110930f749a4711b34d2020-11-24T21:03:50ZengCTU Central LibraryActa Polytechnica CTU Proceedings2336-53822015-02-012114314710.14311/APP.2015.02.01432632Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS CygV. F. Suleimanov0C. W. Mauche1R. Ya. Zhuchkov2K. Werner3Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls University, Sand 1, 72076 T¨ubingen, GermanyLawrence Livermore National Laboratory, L-473, 7000 East Ave., Livermore, CA 94550, USAKazan (Volga region) Federal University, Kremlevskaya str. 18, 42008 Kazan, RussiaInstitute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls University, Sand 1, 72076 T¨ubingen, GermanyThe X-ray spectrum of SS Cyg in outburst has a very soft component that can be interpreted as the fast-rotating optically thick boundary layer on the white dwarf surface. This component was carefully investigated by Mauche (2004) using the Chandra LETG spectrum of this object in outburst. The spectrum shows broad ( ≈5 °A) spectral features that have been interpreted as a large number of absorption lines on a blackbody continuum with a temperature of ≈250 kK. Because the spectrum resembles the photospheric spectra of super-soft X-ray sources, we tried to fit it with high gravity hot LTE stellar model atmospheres with solar chemical composition, specially computed for this purpose. We obtained a reasonably good fit to the 60–125 °A spectrum with the following parameters: T<sub>eff</sub> = 190 kK, log g = 6.2, and NH = 8 · 10<sup>19</sup> cm<sup>−2</sup>, although at shorter wavelengths the observed spectrum has a much higher flux. The reasons for this are discussed. The hypothesis of a fast rotating boundary layer is supported by the derived low surface gravity.https://ojs.cvut.cz/ojs/index.php/APP/article/view/2866
collection DOAJ
language English
format Article
sources DOAJ
author V. F. Suleimanov
C. W. Mauche
R. Ya. Zhuchkov
K. Werner
spellingShingle V. F. Suleimanov
C. W. Mauche
R. Ya. Zhuchkov
K. Werner
Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS Cyg
Acta Polytechnica CTU Proceedings
author_facet V. F. Suleimanov
C. W. Mauche
R. Ya. Zhuchkov
K. Werner
author_sort V. F. Suleimanov
title Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS Cyg
title_short Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS Cyg
title_full Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS Cyg
title_fullStr Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS Cyg
title_full_unstemmed Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS Cyg
title_sort model atmosphere spectrum fit to the soft x-ray outburst spectrum of ss cyg
publisher CTU Central Library
series Acta Polytechnica CTU Proceedings
issn 2336-5382
publishDate 2015-02-01
description The X-ray spectrum of SS Cyg in outburst has a very soft component that can be interpreted as the fast-rotating optically thick boundary layer on the white dwarf surface. This component was carefully investigated by Mauche (2004) using the Chandra LETG spectrum of this object in outburst. The spectrum shows broad ( ≈5 °A) spectral features that have been interpreted as a large number of absorption lines on a blackbody continuum with a temperature of ≈250 kK. Because the spectrum resembles the photospheric spectra of super-soft X-ray sources, we tried to fit it with high gravity hot LTE stellar model atmospheres with solar chemical composition, specially computed for this purpose. We obtained a reasonably good fit to the 60–125 °A spectrum with the following parameters: T<sub>eff</sub> = 190 kK, log g = 6.2, and NH = 8 · 10<sup>19</sup> cm<sup>−2</sup>, although at shorter wavelengths the observed spectrum has a much higher flux. The reasons for this are discussed. The hypothesis of a fast rotating boundary layer is supported by the derived low surface gravity.
url https://ojs.cvut.cz/ojs/index.php/APP/article/view/2866
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AT ryazhuchkov modelatmospherespectrumfittothesoftxrayoutburstspectrumofsscyg
AT kwerner modelatmospherespectrumfittothesoftxrayoutburstspectrumofsscyg
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