Variability of the emission-line spectra and optical continua of Seyfert galaxies. II

Abstract

view Abstract Citations (37) References (35) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Variability of the emission-line spectra and optical continua of Seyfert galaxies. II. Peterson, B. M. ; Foltz, C. B. ; Cranshaw, D. M. ; Meyers, K. A. ; Byard, P. L. Abstract Observations of 10 Seyfert 1 galaxies have been obtained to supplement data presented by Peterson et al. (1982). Relative line strengths and equivalent widths of H-beta and the forbidden O III lines 4959 and 5007 A for 31 Seyfert 1 galaxies are compared with earlier measurements from Lick Observatory, and it is found that the majority of these galaxies underwent spectral changes over a period of 5-8 yr. Continuum and broad emission-line variations are distinguished by assuming that the flux in the forbidden lines is constant over the time scales of interest. Changes in the H-beta flux are usually proportional to changes in the optical continuum, though this is not true for galaxies which have increased in brightness by more than about 0.6 mag. It is suspected that light-travel-time effects are responsible in cases where the broad emission lines do not vary in direct proportion to the continuum flux. Publication: The Astrophysical Journal Pub Date: April 1984 DOI: 10.1086/161917 Bibcode: 1984ApJ...279..529P Keywords: Astronomical Spectroscopy; Emission Spectra; Galactic Radiation; Seyfert Galaxies; Visible Spectrum; Astronomical Catalogs; Continuous Spectra; H Beta Line; Spectral Line Width; Astrophysics full text sources ADS | data products NED (42) SIMBAD (41) Related Materials (2) Part 1: 1982ApJS...49..469P Part 3: 1985ApJ...298..283P