paper

A Deep Multicolor Survey. III. Additional Spectroscopy and Implications for the Number Counts of Faint Quasars

arXiv:astro-ph/9708138 · doi:10.1086/118646

Abstract

We have made spectroscopic identifications of 39 additional quasar candidates from the Deep Multicolor Survey (DMS) of Hall et al. (1996, ApJ, 462, 614, astro-ph/9512052). We have identified 9 new quasars with 0.3 < z < 2.8 and 16.8 < B < 21.6, all from the group of candidates with ultraviolet excess (UVX). No new quasars with z > 3 were found among the observed candidates selected due to their red (B-R) and (V-R) colors. As a result, there are now 55 confirmed quasars in the survey: 42 with 0.3 < z < 2, nine with 2 < z < 3, three with 3 < z < 4, and 1 at z = 4.3. One new quasar, DMS 0059-0055, is very bright with B=16.8 and z=0.3, making its detection by our survey very unexpected. Including this new spectroscopy, the results of the DMS are converging with the predicted space densities of other surveys. In particular, we no longer find an excess of quasars with z < 2.3 and B < 21 in the survey over predictions based on models by Koo & Kron. Also, the excess in the number of quasars seen at z > 3 over predictions based on models by Warren, Hewett, & Osmer is less than previously suggested. We also demonstrate the success of our quasar color modeling which is important in assessing the completeness of our survey.

Accepted for publication in the Astronomical Journal, 15 pages, Latex (style file aaspp4.sty), 2 PostScript figures

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