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A&A Supplement series, Vol. 129, May I 1998, 569-575

Received February 2, 1996; accepted September 19, 1997

Microvariability of the blazar OJ 287gif

G.B. Jia - X.F. Cen - H.Y. Ma - J.C. Wang

Send offprint request: G.B. Jia
Yunnan Observatory, Academia Sinica, P.O. Box 110, Kunming, Yunnan, P.R. China


Results of BVRI CCD photometric monitoring and fast photometry in the I band for the blazar OJ 287 in 1994-1995 are presented. The predicted outburst of the blazar had been observed, the maximum appeared in 1994 November, after that, the luminosity decreased by 1.6 mag for about three months and dropped to near the level in 1994 April. Rapid variations with timescales of minutes, hours and one day were observed in our observations, with small amplitude. The amplitude of the most rapid variations (minutes) is in the range of tex2html_wrap_inline1212. The results of the statistical analysis of the fast photometry data are as follows. In five nights out of six rapid variability appeared in the sampling interval, which ranged from 3.4 minutes to 6.5 minutes, with a rms amplitude of flux variations of tex2html_wrap_inline1214.

The rapid variability can be explained by the model of shocks within turbulent jet or of vortices and magnetic flux tubes on accretion disk.

keywords: BL Lacertae objects: individual: OJ 287 -- galaxies: active

Copyright by the European Southern Observatory (ESO)