Optical variability, absolute luminosity, and the Hubble diagram for QSOs

Abstract

view Abstract Citations (90) References (54) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Optical variability, absolute luminosity, and the Hubble diagram for QSOs. Pica, A. J. ; Smith, A. G. Abstract The physical and cosmological properties of QSOs are assessed in light of 13 years of photometric data for 130 quasars, BL Lac objects, and active galaxies. The mean, base, and maximum flux densities are used to study QSOs in their average, quiescent, and active phases, respectively. Scatter in the Hubble diagram due to optical variability is substantially reduced when log z is plotted versus the three brightness levels. In this fashion, it is found that the brightest quasars at each redshift obey Hubble's relation very precisely when variability is accounted for. Absolute intrinsic luminosities of all sources in the sample are computed from the monochromatic flux densities, using relativistic cosmological models, and the amplitude of variability versus absolute luminosity relation is used to discriminate between two classes of QSO models. Results favor a black hole model in which discrete events are superposed on a continuously accreting disk. Publication: The Astrophysical Journal Pub Date: September 1983 DOI: 10.1086/161257 Bibcode: 1983ApJ...272...11P Keywords: Bl Lacertae Objects; Hubble Diagram; Luminosity; Periodic Variations; Quasars; Spectral Energy Distribution; Active Galaxies; Astronomical Models; Astronomical Spectroscopy; Black Holes (Astronomy); Light Curve; Radiant Flux Density; Red Shift; Astrophysics full text sources ADS | data products SIMBAD (131) NED (95)