Optical Variability of Twenty-Two Quasi-Stellar Objects

R. J. Angione, H. J. Smith
1972 Symposium - International astronomical union  
Light fluctuations have been found in all 22 QSOs studied by measurement of plates from the Harvard collection, which cover the last eighty years. The conclusions of this study are: (i) There appear to be at least three general classes of variation: (a) erratic, small-amplitude variations, (b) erratic, large-amplitude variations, and (c) slow quasi-periodic variations, e.g. as in 3C 273; (ii) No significant differences were detected between the rates of rise and decline of luminosity; (iii)
more » ... nite secular trends over at least 50 years were found in 5 QSOs; (iv) No simple clearcut periods greater than one year have been found; (v) There may be a trend of decreasing amplitude of fluctuations in apparent magnitude with increasing luminosity.
doi:10.1017/s0074180900005490 fatcat:g6oiq6xljjbobkf3clz5snqnrq