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Volume 315 - The Golden Age of Cataclysmic Variables and Related Objects IV (GOLDEN 2017) - Opening Remarks
The impact of SUZAKU on the knowledge of The Physics of CVs
T. Hayashi
Full text: pdf
Pre-published on: 2018 July 03
Published on: 2018 September 13
Suzaku satellite observed dozens of WD binaries and gave us various findings and knowledge. In this paper, four topics are picked up. (1) From a nova outburst of V2491 Cyg, a very hard non-thermal component with Γ= 0.1 $\pm$0.2 was found. Mass accretion seemed to be rekindled 30 days after the nova and its X-ray spectrum is similar to that of intermediate polars. (2) In a nova outburst of a symbiotic Mira star V407 Cyg, a non-equilibrium ionization (NEI) plasma emission was found, which shows asymmetry in the environment encountered by the nova ejecta. The coincidental GeV γ-ray decline/X-ray rise can be explained by the stalling of the shock front because of the ejecta running into the red giant photosphere. (3) X-ray spectra of five symbiotic stars (CD-28 3719, Hen 3-1591, Hen 3-461, EG And and 4 Dra) have hot thermal plasma of $T_{\rm max}$ > 3 keV. To reproduce thetemperature, X-ray energy source should be ascribed to release of the gravitational potential in boundary layers. (4) X-ray spectrum of γ Cas can be reproduced by a single-temperature thermal plasma model of 15 keV.
X-ray dips of order of 10$^4$ s can be explained by partial covering absorption. A WD binary is more likely for γ Cas identity because of its spectrum without power-law component and consistency of the covering fractions of absorbers and dip duration.
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