Strong Optical Flare from Blazar OJ 287 Detected by ASAS-SN

ATel #8372; B. J. Shappee (Hubble Fellow, Carnegie Observatories), K. Z. Stanek, T. W.-S. Holoien, J. S. Brown, C. S. Kochanek, D. Godoy-Rivera, U. Basu (Ohio State), J. L. Prieto (Diego Portal es; MAS), D. Bersier (LJMU), Subo Dong, Ping Chen (KIAA-PKU), J. Brimacombe (Coral Towers Observatory)
on 5 Dec 2015; 23:31 UT
Credential Certification: Benjamin Shappee (bshappee@obs.carnegiescience.edu)

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During the ongoing All Sky Automated Survey for SuperNovae (ASAS-SN or "Assassin"), using data from three separate cameras on the quadruple 14-cm "Brutus" telescope in Haleakala, Hawaii, we detect a strong optical flare from the blazar OJ 287, a suspected supermassive black hole binary. This is the largest flare seen in more than 800 images covering nearly 4 years of ASAS-SN data. The ASAS-SN light curve from the past 100 days can be seen here. Eight images taken on UT 2015-12-03.59 reveal the beginning of the V-band flare which strengthened (Delta V~1.5 mag) in our most recent images taken on UT 2015-12-05.59. The last four ASAS-SN epochs had the following V-band photometry:

 
JD           Obs. UT Date     V mag  V err   Flux(mJy)  Flux err      
2457343.002  2015-11-16.502   15.37  0.11    2.719      0.271             
2457343.002  2015-11-16.502   15.20  0.15    3.195      0.437             
2457343.002  2015-11-16.502   15.04  0.08    3.715      0.265             
2457343.003  2015-11-16.503   15.32  0.10    2.848      0.267             
2457343.003  2015-11-16.503   15.25  0.10    3.036      0.276             
2457343.004  2015-11-16.504   15.25  0.09    3.059      0.244             
2457343.004  2015-11-16.504   15.32  0.12    2.846      0.301             
2457344.993  2015-11-18.493   15.17  0.09    3.292      0.282             
2457344.993  2015-11-18.493   15.46  0.13    2.519      0.289             
2457344.994  2015-11-18.494   15.07  0.09    3.586      0.289             
2457344.994  2015-11-18.494   15.25  0.10    3.038      0.276             
2457344.994  2015-11-18.494   15.24  0.13    3.088      0.376             
2457344.995  2015-11-18.495   15.13  0.09    3.404      0.292             
2457344.995  2015-11-18.495   15.23  0.10    3.119      0.290         
2457360.089  2015-12-03.589   14.02  0.03    9.501      0.300             
2457360.089  2015-12-03.589   14.04  0.03    9.252      0.282             
2457360.089  2015-12-03.589   13.94  0.04    10.179     0.359             
2457360.090  2015-12-03.590   13.93  0.03    10.229     0.310             
2457360.090  2015-12-03.590   13.96  0.03    9.981      0.255             
2457360.090  2015-12-03.590   13.99  0.04    9.740      0.376             
2457360.091  2015-12-03.591   13.94  0.03    10.210     0.289             
2457360.091  2015-12-03.591   13.98  0.03    9.817      0.270             
2457362.093  2015-12-05.593   13.58  0.02    14.214     0.284             
2457362.093  2015-12-05.593   13.55  0.02    14.554     0.286             
2457362.094  2015-12-05.594   13.53  0.02    14.851     0.283             
2457362.094  2015-12-05.594   13.61  0.03    13.858     0.319             
2457362.094  2015-12-05.594   13.57  0.02    14.381     0.300             
2457362.095  2015-12-05.595   13.53  0.02    14.848     0.275             
2457362.095  2015-12-05.595   13.53  0.02    14.886     0.294 

We thank LCOGT and its staff for their continued support of ASAS-SN. ASAS-SN is supported by NSF grant AST-1515927, the Mt. Cuba Astronomical Foundation, the Center for Cosmology and AstroParticle Physics (CCAPP) at OSU, and the Robert Martin Ayers Sciences Fund. For more information about the ASAS-SN project, see the ASAS-SN Homepage and the list of all ASAS-SN transients.