Study of Rapid Variability of the Blazar OJ 287 in the Radio and Optical Ranges

Abstract

The extragalactic radio source OJ 287 is one of the most studied blazars. A huge amount of data has been accumulated on it (for more than 40 years in the radio range and more than 100 in the optical). Studies of the rapid variability in the radio flux and stellar magnitude of this object with characteristic times ranging from a few hours to several days are of interest in connection with the possible presence in this radio source of a system of binary black holes that includes a central object and its satellite. Here we present the results of searches for and studies of the intraday variability (IDV) and interday variability of the radio source OJ 287 (March-May 2019) at frequencies of 6.1 and 6.7 GHz on the telescopes at VIRAC (Ventspils International Radioastronomy Center, Latvia) compared with optical V, R, and I band variability (April-May 2019). Optical light curves were obtained on the 1.2-m Schmidt system telescope at the Baldone Astronomical Observatory, Latvia, on the 1-m VNT telescope at the Vihorlat Astronomical Observatory, Slovakia, and on the AZT-3 telescope at the Mayaki Observational Station of the I. I. Mechnikov Odessa National University, Ukraine. Similarities are found in the long-term quasiperiods in the radio (15, 42 days) and optical (13, 36-37 days) ranges. The minimum characteristic time for changes in the flux density was 1.4 hours and 0.6 hours at frequencies of 6.7 and 6.1 GHz with fundamental quasiperiods of about 5 and 2-3 hours during different observation sessions. The results obtained here are compared with those of other authors.