V4641 Sgr: new optical flaring
ATel #309; I. Bikmaev (KSU), I. Khamitov, Z. Aslan (TUG), N. Sakhibullin (KSU), R. Burenin, M Pavlinsky (IKI), M. Revnivtsev, R. Sunyaev (IKI, MPA)
on 18 Jul 2004; 13:14 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: M. Revnivtsev (mikej@mpa-garching.mpg.de)
Subjects: Optical, Request for Observations, Black Hole
Referred to by ATel #: 315
We have performed photometric time-series observations (Rc-band) of X-ray
binary system V4641Sgr with the Russian-Turkish telescope RTT150
at the TUBITAK National Observatory (Turkey) during the
period of 18:33-23:32 UT, July 17,2004. Several optical flaring with
increasing of brightness amplitude up to 0.6 mag have been detected.
Obtained Light curve with the time resolution of 16.8 sec
can be seen in http://db.rsdc.rssi.ru/V4641Sgr/2004/lc040717.jpg
Orbital variations of V4641 Sgr in quiescence (Goranskij et al.,
Astron.Rep., 2003, v.80, N9) with data points obtained on July 17, 2004
can be seen in http://db.rsdc.rssi.ru/V4641Sgr/2004/ph040717.jpg
Given strong optical variability the source obviously in some active
state. Simultaneous X-ray and optical observations are crucial
for investigations of the nature of the observed activity.
Lightcurve of V4641Sgr on July 17, 2004
