Rapid optical variability of V4641 Sgr (=SAX J1819.3-2525)
ATel #174; I. Khamitov, Z. Aslan (TUG), K. Yakut (EgeU), I. Bikmaev, R. Gumerov, N. Sakhibullin (KSU), R. Sunyaev, M. Revnivtsev (IKI, MPA), M. Pavlinsky (IKI)
on 7 Aug 2003; 20:11 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: M. Revnivtsev (mikej@mpa-garching.mpg.de)
Subjects: Optical, Request for Observations, Binary, Black Hole, Transient
Referred to by ATel #: 175, 297
The X-ray binary system V4641 Sgr (=SAX J1819.3-2525) was observed in Rc
band with the 1.5-m Russian-Turkish telescope RTT150 at Bakyrlytepe
during the period 19:01-22:16 UT, Aug. 6, 2003. The Rc magnitude of the
source averaged over all observations was m_Rc~11.7. Time resolution of the
photometric data is 9.7 sec. The observed light curve demonstrates strong
aperiodic variability at all time scales, from tens of seconds to hours.
Several spikes weer observed with duration of the order of a minute and
amplitudes up to 1 magnitude. Power spectrum of the optical flux variations
could be described by a power law with the slope -1.8 in the
frequency band 1e-4 - 0.04 Hz.
Lightcurve of V4641 Sgr
