CCD Monitoring of Blazar OJ287 from MIRO

ATel #4021; Sunil Chandra, Shashikiran Ganesh, K. S. Baliyan
on 7 Apr 2012; 15:58 UT
Credential Certification: Sunil Chandra (sunil.chandra355@gmail.com)

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A sample of Blazars' are regularly monitored using CCD Camera, Near Infrared Camera & Spectrograph (NICMOS/NICS) and Photo-polarimeter as a back-end instruments on 1.2 m Telescope at Mt. Abu Infrared Observatory(MIRO). An Automated robotic optical telescope (0.5 m) at same site is dedicated to the long term monitoring of blazars and also is the part of blazar monitoring program. Following the Atel #4020 by Sanatengelo.et.al, we carried out the differential photometry of the data taken on 16 March 2012 and 26 March 2012. The present data for blazar OJ287 was taken using Liquid Nitrogen CCD-Camera ( 1152 x 1296 ) on f/13 Cassegrain focus of 1.2 telescope at MIRO. The twilight flat field images taken during respective nights are used to generated the master flat. The bias frames taken during the course of respective nights, are used for master bias. The proper flat field and bias correction is performed for both the nights. The Instrumental Magnitudes obtained is calibrated using known comparison stars lying in the same field (Comparison Stars: Fiorucci et. al A&AS 1996, 116, 403). The R and V band magnitudes are as follows: 16th March 2012 56002.87 (MJD*) R: 14.14 +/- 0.007 V: 56002.88 (MJD) 14.50 +/- 0.01 26th March 2012 56012.81 (MJD) R: 14.16 +/- 0.003 * MJD=JD-2400000.5 The above results coupled with the same reported by Atel #4020, indicate the blazar OJ287 has brightened 0.38 mag (14.14 to 13.78) in R and 0.16 mag (14.50 to 14.34) in V band within about 65 hrs though the data in between is missing. This gives a constraint on the timescale of variation. This activity can be classified as intermediate kind of flaring activity as inferred by Sanatengelo et al (Atel #4020).