A study of the optical variability of the quasistellar objects in the 13h +36 field - I: The blue magnitudes.
Abstract
The optical variability of 148 radio-quiet quasars listed in the catalog of Braccesi et al. (1970) is studied on the basis of 22 blue and 12 visual plates of the 13 h, plus 36 deg field obtained over a five-year period. The optical activity of these objects is compared with that of 35 radio-emitting quasars and galaxies compiled from several surveys. It is found that: (1) at least 132 of the 148 objects studied must be variable; (2) optically violent variable objects are about 10 times less frequent among the radio-quiet than the radio-emitting quasars, but even the radio-quiet objects exhibit a moderate amount of burst activity; (3) there is no relation between absolute magnitude and variability over the very large range of absolute magnitudes among the radio-quiet objects; and (4) the rms variance of the objects both in the sample studied and in the comparison sample increases regularly with the time interval between observations, suggesting a characteristic time of about 5 months for the phenomena underlying the variability.
- Publication:
-
Astronomy and Astrophysics Supplement Series
- Pub Date:
- March 1979
- Bibcode:
- 1979A&AS...35..391B
- Keywords:
-
- Quasars;
- Stellar Magnitude;
- Ultraviolet Astronomy;
- Variable Stars;
- Astronomical Catalogs;
- Astronomical Photography;
- Cosmology;
- Root-Mean-Square Errors;
- Stellar Luminosity;
- Astronomy;
- Quasi-Stellar Objects:Variations