Broad Absorption-Line Time Variability in the QSO CSO 203
Abstract
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 λ1397 and C IV λ1549. We also note possible variations in the N V λ1240 and Al III λ1857 absorption troughs. A broad-band monitoring effort during this period shows that the continuum level remained constant to within 10%. 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.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 1992
- DOI:
- 10.1086/171768
- Bibcode:
- 1992ApJ...397...81B
- Keywords:
-
- Absorption Spectra;
- Astronomical Spectroscopy;
- Line Spectra;
- Quasars;
- Aluminum;
- Carbon;
- Nitrogen;
- Photoionization;
- Photons;
- Silicon;
- Astrophysics;
- GALAXIES: QUASARS: ABSORPTION LINES;
- GALAXIES: QUASARS: INDIVIDUAL ALPHANUMERIC: CSO 203