Long-term variability of a complete sample of quasars

Journal Article · Sun Jul 01 00:00:00 EDT 1990 · Astronomical Journal; (USA)

DOI:https://doi.org/10.1086/115489· OSTI ID:6863928

Cristiani, S; Vio, R; Andreani, P ^[1]

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1. Padova Universita, Padua (Italy)

The long-term variability of a complete sample of quasars selected in the field of the SA 94 has been investigated. Using Schmidt plates covering a time baseline of seven years, about one-third of the quasars are found to be variable. It is suggested that all the quasi-stellar objects are variable with amplitudes of a few tenths of a magnitude on timescales of the order of some years in their restframes. The application of the variability technique to the selection of complete samples of quasars is discussed. The timescales estimated can be easily accounted for in the accreting black hole with thermal and viscous timescales. The variability is found to be correlated with the absolute magnitude and/or the redshift. 21 refs.

• OSTI ID: 6863928
• Journal Information: Astronomical Journal; (USA), Journal Name: Astronomical Journal; (USA) Vol. 100; ISSN 0004-6256; ISSN ANJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BLACK HOLES
BRIGHTNESS
CAMERAS
CORRELATIONS
COSMIC RADIO SOURCES
GALAXY NUCLEI
MATHEMATICS
OPTICAL PROPERTIES
PHOTOGRAPHY
PHYSICAL PROPERTIES
QUASARS
RED SHIFT
STATISTICS
VARIATIONS