Bibcode
Zurita, C.; Casares, J.; Hynes, R. I.; Shahbaz, T.; Charles, P. A.; Pavlenko, E. P.
Referencia bibliográfica
Monthly Notices of the Royal Astronomical Society, Volume 352, Issue 3, pp. 877-886.
Fecha de publicación:
8
2004
Número de citas
16
Número de citas referidas
15
Descripción
We present the results of optical and infrared photometry of the
quiescent X-ray transient V404 Cyg during the period 1992-2003. The
ellipsoidal modulations extracted from the most complete data bases
(years 1992, 1998 and 2001) show unequal maxima and minima with relative
strength varying from year to year although their peak-to-peak
amplitudes remain roughly constant at 0.24 +/- 0.01 mag. Fast optical
variations superimposed on the double-humped ellipsoidal modulation of
the secondary star were detected every year with a mean amplitude of
~0.07 mag. We have not found significant changes in the activity during
this decade which indicates that this variability is probably not
connected to the 1989 outburst. We have found periodicities in the 1998
and 2001 data near the 6-h quasi-periodicity observed in 1992, although
we interpret it as a consequence of the appearance of a flare event
almost every night. Significant variability is also present in the I and
near-infrared (J and Ks) bands and this decreases slightly or
remains approximately constant at longer wavelengths. A
cross-correlation analysis shows that both the R and I emission are
simultaneous down to 40 s.