Optical brightness and polarization of quasars and related objects

Photographic monitoring of over 130 quasars and related objects has shown definite optical variability to be present in nineteen of these objects and suspected variability in forty-four others. Regular observations of the optically violent variables OB 338, OX 074, PSK 0518 + 16, PSK 2345-16, NRAO 512, and 3C 371 have revealed that these objects continue to undergo violent optical outbursts of a magnitude or more with the flare and subsequent return to minimum sometimes occurring within a few weeks. In addition, optical variability was observed for the first time in the objects PKS 0202-17, PKS 0222-23, PKS 1252 + 11, and NRAO 140. Both OQ 208 and PKS 0222-23 showed a total range of variability of a magnitide or more. The optically violent quasar 3C 446 underwent a 2./sup m/5 flare in 1974 with an extremely rapid decay time. Two types of characteristic variability were observed. The first was a violent optical outburst with rapid rise and decay times. The second type of characteristic variability was a slowly varying component which appeared as a gradual rise and fall in optical brightness. There is observational indication that major flares in optically violent objects tend to be followed by a succession of minor flares of decreasing amplitude superimposed upon the decline in brightness following the major flare. This effect was observed in NRAO 512, OX 074, PKS 2345-16, PKS 2209 + 08, and possibly OQ 208 and PKS 0222-23. Optical linear polarimetric observations were conducted photographically on BL Lacertae, 3C 120, and 3C 273. These observations indicate that the peculiar object BL Lac has a very large, rapidly varying linearly polarized component. There seems to be a positive correlation between the optical activity of an object and the magnitude and variability of its linearly polarized component