Broad absorption-line time variability in the QSO CSO 203

• Published in: The Astrophysical journal Vol. 397; no. 1; pp. 81 - 87
• Main Authors: Barlow, Thomas A., Junkkarinen, Vesa T., Burbidge, E. M., Weymann, Ray J., Morris, Simon L., Korista, Kirk T.
• Format: Journal Article
• Language: English
• Published: Legacy CDMS University of Chicago Press 20.09.1992
• Subjects: Astronomy; Astrophysics; Earth, ocean, space; Exact sciences and technology; Quasars; Quasars. Active or peculiar galaxies, objects, and systems; Stellar systems. Galactic and extragalactic objects and systems. The universe; Quasar; Absorption line; Silicon IV; Nitrogen V; Variability; Equivalent width; Broad line region; Aluminium III; Carbon IV; Spectroscopical observation; Optical spectrum
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1086/171768

We present spectroscopy of the BALQSO CSO 203 during four epochs over a 17-month time span. These data show three distinct levels in the broad absorption lines (BALs) of Si IV 1397A and C IV 1549A. We also note possible variations in the N V 1240A and Al III 1857A absorption troughs. A broad-band monitoring effort during this period shows that the continuum level remained constant to within 10 percent. We argue that the triggering mechanism for the absorption-line changes is most likely synchronous with the continuum source photons; however, no correlation with the central source has yet been found. The observed variations are consistent with changes in the ionization level in the broad absorption-line region (BALR). We discuss possible mechanisms for these changes and the implications for the structure of the BALR.