Magellan Spectroscopy of AGN Candidates in the COSMOS Field
Abstract
We present spectroscopic redshifts for the first 466 X-ray- and radio-selected AGN targets in the 2 deg2 COSMOS field. Spectra were obtained with the IMACS instrument on the Magellan (Baade) telescope, using the nod-and-shuffle technique. We identify a variety of type 1 and type 2 AGNs, as well as red galaxies with no emission lines. Our redshift yield is 72% down to iAB=24, although the yield is >90% for iAB<22. We expect the completeness to increase as the survey continues. When our survey is complete and additional redshifts from the zCOSMOS project are included, we anticipate ~1100 AGNs with redshifts over the entire COSMOS field. Our redshift survey is consistent with an obscured AGN population that peaks at z~0.7, although further work is necessary to disentangle the selection effects.
Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by AURA, Inc., under NASA contract NAS 5-26555 and based on data collected at the Magellan Telescope, which is operated by the Carnegie Observatories.- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- September 2007
- DOI:
- 10.1086/516578
- arXiv:
- arXiv:astro-ph/0606016
- Bibcode:
- 2007ApJS..172..383T
- Keywords:
-
- Galaxies: Active;
- Galaxies: Quasars: General;
- Surveys;
- Astrophysics
- E-Print:
- 19 pages, 14 figures. Accepted to ApJS special COSMOS issue. The full electronic version of Table 2 can be found at http://shaihulud.as.arizona.edu/~jtrump/tab2.txt