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Correlated X-Ray and Optical Variability in V404 Cygni in Quiescence

Hynes, R. I.; Charles, P. A.; Garcia, M. R.; Robinson, E. L.; Casares, J.; Haswell, C. A.; Kong, A. K. H.; Rupen, M.; Fender, R. P.; Wagner, R. M.; Gallo, E.; Eves, B. A. C.; Shahbaz, T. and Zurita, C. (2004). Correlated X-Ray and Optical Variability in V404 Cygni in Quiescence. Astrophysical Journal, 611 L125-L128.

DOI (Digital Object Identifier) Link: http://dx.doi.org/10.1086/424005
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Abstract

We report simultaneous X-ray and optical observations of V404 Cyg in quiescence. The X-ray flux varied dramatically by a factor of 20 during a 60 ks observation. X-ray variations were well correlated with those in Hα, although the latter include an approximately constant component as well. Correlations can also be seen with the optical continuum, although these are less clear. We see no large lag between X-ray and optical line variations; this implies they are causally connected on short timescales. As in previous observations, Hα flares exhibit a double-peaked profile suggesting emission distributed across the accretion disk. The peak separation is consistent with material extending outward to at least the circularization radius. The prompt response in the entire Hα line confirms that the variability is powered by X-ray (and/or EUV) irradiation.

Item Type: Journal Article
ISSN: 1538-4357
Keywords: accretion, accretion disks—binaries: close—stars: individual (V404 Cygni)— X-rays: binaries
Academic Unit/Department: Science > Physical Sciences
Interdisciplinary Research Centre: Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)
Item ID: 10937
Depositing User: Astrid Peterkin
Date Deposited: 02 Jul 2008
Last Modified: 02 Dec 2010 20:08
URI: http://oro.open.ac.uk/id/eprint/10937
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