Open AccessCorrelated X-Ray and Optical Variability in V404 Cygni in Quiescence
Author(s) -
R. I. Hynes,
P. A. Charles,
M. R. Garcia,
E. L. Robinson,
J. Casares,
C. A. Haswell,
A. K. H. Kong,
M. Rupen,
R. P. Fender,
R. M. Wagner,
Elena Gallo,
B. A. C. Eves,
T. Shahbaz,
C. Zurita
Publication year - 2004
Publication title -
the astrophysical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.376
H-Index - 489
eISSN - 1538-4357
pISSN - 0004-637X
DOI - 10.1086/424005
Subject(s) - astrophysics , physics , radius , line (geometry) , lag , x ray , accretion (finance) , flux (metallurgy) , flare , optics , chemistry , computer network , geometry , computer security , mathematics , computer science , organic chemistry
We report simultaneous X-ray and optical observations of V404 Cyg inquiescence. The X-ray flux varied dramatically by a factor of >20 during a 60ksobservation. X-ray variations were well correlated with those in Halpha,although the latter include an approximately constant component as well.Correlations can also be seen with the optical continuum, although these areless clear. We see no large lag between X-ray and optical line variations; thisimplies they are causally connected on short timescales. As in previousobservations, Halpha flares exhibit a double-peaked profile suggesting emissiondistributed across the accretion disk. The peak separation is consistent withmaterial extending outwards to at least the circularization radius. The promptresponse in the entire Halpha line confirms that the variability is powered byX-ray (and/or EUV) irradiation.Comment: 5 pages; Accepted for publication in the Astrophysical Journal Letter
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