20–100 keV properties of cataclysmic variables detected in the INTEGRAL/IBIS survey

• Published in: Monthly notices of the Royal Astronomical Society Vol. 372; no. 1; pp. 224 - 232
• Main Authors: Barlow, E. J., Knigge, C., Bird, A. J., J Dean, A., Clark, D. J., Hill, A. B., Molina, M., Sguera, V.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 11.10.2006; Blackwell Science; Oxford University Press
• Subjects: Astronomy; Data analysis; Earth, ocean, space; Emissions; Energy; Exact sciences and technology; Gamma ray astronomy; gamma-rays: observations; novae cataclysmic variables; Stars & galaxies; Surveying; surveys; X-rays: binaries; surveys; X-rays: binaries; gamma-rays: observations; novae cataclysmic variables; Star light; keV range; Accretion; Hard x radiation; Novae; Light curves; Binary X ray source; Cosmic x-ray sources; Intermediate polar; Quiescence; Gamma radiation; X-ray binary stars; Correlations; Astronomical catalogues; Cataclysmic variable stars
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1111/j.1365-2966.2006.10836.x

Analysis of INTEGRAL/IBIS survey observations has revealed that the rare intermediate polar and asynchronous polar cataclysmic variables (CVs) are consistently found to emit in the 20–100 keV energy band, whereas synchronous polars and the common non-magnetic CVs rarely do so. From the correlation of a candidate INTEGRAL/IBIS survey source list with a CV catalogue, 15 CV detections by IBIS have been established including a new INTEGRAL source IGR J06253+7334. The properties of these sources and four additional CV candidates are discussed in the context of their 20–100 keV emission characteristics, and we conclude that the INTEGRAL mission is an important tool in the detection of new magnetic CV systems. Furthermore, analysis of the time-averaged spectra of CVs detected by INTEGRAL indicates that although there is little difference between the spectral slopes of the different subtypes, intermediate polars may be considerably more luminous than polars in the soft gamma-ray regime. We also present the detection of an unusual high-energy burst from V1223 Sgr discovered by the inspection of the IBIS light curve. Additionally, we have compared the IBIS and optical American Association of Variable Star Observers (AAVSO) light curves of SS Cyg and extracted IBIS spectra during single periods of optical outburst and quiescence. We find that the 20–100 keV flux is an order of magnitude greater during optical quiescence. This is in agreement with previous studies which show that the hard X-ray component of SS Cyg is suppressed during high accretion states.