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P.B. Hall, H.K.C. Yee (U. Toronto), H. Lin (U. Arizona), S.L. Morris (DAO), D.R. Patton (U. Toronto), M. Sawicki (Caltech), C.W. Shepherd, G. Wirth (Keck), R.G. Carlberg (U. Toronto), J. Bechtold (U. Arizona), R. Elston (U. Florida)
We present a sample of 42 Active Galactic Nuclei (AGN) serendipitously discovered in the Canadian Network for Observational Cosmology field galaxy redshift survey (CNOC2). Redshifts of these AGN range from z=0.086 to z=4.67, and have an average MB = -21.7, well below the traditional quasar/Seyfert division at MB = -23.
This sample was selected without regard to the objects' colors, and thus it serves as an independent check on color selection techniques used in many quasar surveys (e.g. 2dF and Sloan).
The results are in general reassuring: color selection does not appear to introduce extreme biases.
The equivalent width distributions for the various emission lines seen in the CNOC2 AGN show no significant differences from previous surveys.
Simple color-color diagram selection criteria can recover about 86% of the CNOC2 AGN. However, several of the most unusual objects would be overlooked.
Also, this sample shows a higher incidence of associated Mg\,{\sc ii}\,\lambda2798 absorption than in previous surveys and an incidence of associated C\,{\sc iv}\,\lambda1549 absorption more similar to radio-selected quasar samples than optically-selected ones. This may indicate an anticorrelation between associated absorption and optical luminosity.
The CNOC2 AGN sample contains several unusual objects, including one with a candidate double-peaked Mg\,{\sc ii} emission line of very high equivalent width, one with an [O\,{\sc iii}]\,\lambda3133 broad absorption line, one with broad H\alpha but only an absorption-line spectrum in the rest-frame UV, and the two least luminous z>4 quasars discovered to date.
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The author(s) of this abstract have provided an email address for comments about the abstract: hall@astro.utoronto.ca