DETECTION OF HIGH OPTICAL ACTIVITY OF BLAZAR OJ287
ATel #4020; M. M.M. Santangelo (O. A.C.)
on 6 Apr 2012; 14:00 UT
Credential Certification: Filippo Mannucci (filippo@arcetri.astro.it)
Subjects: Optical, Blazar
M.M.M. Santangelo, Astronomical Observatory of Capannori (OAC) Italy, recently performed optical CCD photometric monitoring of the blazar OJ287.
This monitoring is part of the CATS (Capannori Astronomical Transient Survey) project.
This CCD photometry of OJ287 was obtained with OAC's 0.30-m f/10 telescope equipped with a SBIG ST-9XE CCD camera + BVRI (Johnson/Cousins) filters in the nights of March 28th, March 29th, and April 1st.
Bias images, master darks and master flats (both twilight sky and dome flats) were obtained each night.
The photometric calibration was performed on every night on the secondary UBVRI standards around the so-called "dipper asterism" in M67.
Our V and R magnitudes are as follows:
2012 March 28.91UT R = 13.78 +/-0.01 and V = 14.34 +/- 0.02;
2012 March 29.86UT R = 13.84 +/-0.01 and V = 14.29 +/-0.02;
2012 April 1.84UT R = 13.95 +/-0.03 and V = 14.30 +/-0.04.
This photometry shows that OJ287 is at the brightest photometric levels of the last two years.
OJ287 is now only 0.3 magnitudes fainter than the outburst of the late 2005, and about an half magnitude fainter than that of the outburst of 1994, but by far fainter than the great outbursts of 1983 and 1972.
This high optical activity of OJ287 apparently contradicts some of the predictions made by Sundelius et al.(ApJ 484,180,1997); their fig.6 with a prediction for a small outburst by 2014-2015 and not in 2012.
Apparently this recent activity is not in agreement with the ~12 years cycle discovered by Sillanpaa et al.(A&A 315, L13, 1996).
The high optical activity of OJ287 observed at OAC was not predicted by Valtonen (2007, ApJ 659, 1074) based on the precessing binary black hole model.
Infact in tables 1,2,3 in Valtonen's paper there are no predicted outbursts between late 2007 and late 2015 (or early 2016).
Smaller outbursts, flickering and synchrotron flares (Dultzin-Hacyan et al., 1997, Rev.Mex.A&A 33, 17) are not uncommon in blazars.
But the recent fairly high photometric activity of OJ287 can be classified at an intermediate level between the smaller flares and the biggest outbursts.
