AIRA optical observations of V404 Cyg
ATel #7730; A. Sonka (AIRA), V. Tudose (ISS), A. Nedelcu (AIRA), M. Popescu (AIRA)
on 29 Jun 2015; 21:04 UT
Credential Certification: Valeriu Tudose (tudose@spacescience.ro)
Subjects: Optical, Binary, Black Hole, Transient
We report optical photometry of V404 Cyg on the night of 2015 June 27/28, during a 4 hours observing run (20:12 UT- 00:15 UT), using the 0.5m Cassegrain telescope of the Astronomical Institute of Romanian Academy (AIRA). The observations (60s exposure time) were taken in the Johnson V filter with an SBIG STL11000M CCD camera.
The light-curve (see link below) was obtained by differential photometry using 000-BCL-467, 000-BCL-452 and 000-BCL-458 (AAVSO International Database) as comparison stars. Their V magnitudes were taken from the AAVSO Photometric All-Sky Survey (APASS).
Towards the end of the run, at about 22:52 UT, the target experienced a sudden increase in brightness, by more than 2 magnitudes. Significant variability, by up to 1 magnitude, at timescales of minutes, was detected during the peak of this flare.
We continue to monitor the behavior of V404 Cyg with nightly observations (weather permitting).
V404 Cyg light-curve