Very Large Array observations of rapid non-periodic variations in OJ 287

The authors observed BL Lacertae object OJ 287 with the Very Large Array at 5, 15 and 22 GHz several times in early 1983. The 5-GHz data, taken coincident with 22-GHz observations of previous workers show OJ 287 to have decreased in flux by about 1.8% in an irregular way over a span of about 7 h, and to have fluctuated by about 0.5% on a timescale of about 15 min. Brightness temperatures derived from causality constraints range between 1016 and 1020K. At 5 GHz there was no harmonic component to the intensity of OJ 287 which exceeded 0.1% of the mean for any period between 80 and 5,000 s. The limits at 15 and 22 GHz were 2% and 0.8%, respectively. (author)