The Quasar OJ 287 seems to have reached an optical maximum

ATel #13677; David Reinhart, Remco Steineke, Kilian Schoch, Lukas Waller, Johannes Knött, Dirk Seifert, Adrian Scherbantin, Nils Zottmann, Martin Feige, Christian Lorey (all Friedrich-Koenig-Gymnasium / Hans-Haffner-Sternwarte), Karl Mannheim (Universitaet Wuerzburg), Dominik Elsaesser (TU Dortmund)
on 28 Apr 2020; 14:22 UT
Credential Certification: Dominik Elsaesser (dominik.elsaesser@tu-dortmund.de)

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The BL Lac - type quasar OJ 287 (ICRS coords. (ep=J2000): RA 08 54 48.875 +20 06 30.643) is a massive binary black hole system in the constellation Cancer.
Since the beginning of March of this year, there has been a significant increase in brightness in the optical regime as well as in the UV and X-ray range (ATELs #13637, #13658).
In the last few nights, our data show that the increase in brightness observed over a period of 6 weeks (delta R mag ca. 1.25) seems to have stopped and a maximum may have been reached on JD 2458963 / 2458964. Since then the optical brightness has decreased slightly.
It is noteworthy that both the brightness reached at maximum, and the overall shape of the trend bears intriguing similarities to previously registered outbreaks in 2015/16 and 2016/17. We encourage follow - up observations.


R - band magnitudes:

JD 2458950.4641: 14.241 +/- 0.010
JD 2458955.4572: 14.017 +/- 0.008
JD 2458957.3186: 13.896 +/- 0.014
JD 2458960.5131: 13.790 +/- 0.012
JD 2458963.3458: 13.615 +/- 0.006
JD 2458964.3998: 13.615 +/- 0.007
JD 2458965.3656: 13.636 +/- 0.005
JD 2458966.3508: 13.597 +/- 0.006
JD 2458966.4644: 13.605 +/- 0.008
JD 2458967.3412: 13.645 +/- 0.006
JD 2458967.3997: 13.643 +/- 0.007


V - band magnitudes:

JD 2458950.4673: 14.632 +/- 0.013
JD 2458955.4603: 14.373 +/- 0.008
JD 2458957.3218: 14.280 +/- 0.015
JD 2458960.5184: 14.160 +/- 0.016
JD 2458963.3490: 13.958 +/- 0.006
JD 2458964.4030: 13.964 +/- 0.008
JD 2458965.3688: 14.004 +/- 0.006
JD 2458966.3440: 13.943 +/- 0.006
JD 2458966.4675: 13.948 +/- 0.009
JD 2458967.3444: 13.981 +/- 0.007
JD 2458967.4029: 14.005 +/- 0.007


B - band magnitudes:

JD 2458950.4705: 15.041 +/- 0.022
JD 2458955.4635: 14.794 +/- 0.010
JD 2458957.3250: 14.727 +/- 0.019
JD 2458960.5217: 14.581 +/- 0.028
JD 2458963.3522: 14.329 +/- 0.009
JD 2458964.4062: 14.348 +/- 0.011
JD 2458965.3720: 14.381 +/- 0.008
JD 2458966.3474: 14.370 +/- 0.009
JD 2458966.4707: 14.349 +/- 0.014
JD 2458967.3476: 14.406 +/- 0.010
JD 2458967.4061: 14.401 +/- 0.011


These measurements are carried out as part of the long-term AGN monitoring program of the Naturwissenschaftliches Labor fuer Schueler am Friedrich-Koenig-Gymnasium (FKG), the Universitaet Wuerzburg and TU Dortmund with the 0.5m telescope at the school and university observatory Hans-Haffner-Sternwarte in Hettstadt (Germany).

OJ 287 has been monitored in this program since December 2013 and we plan to continue monitoring over the next years.

Naturwissenschaftliches Labor fuer Schueler am Friedrich-Koenig-Gymnasium