Magellan spectroscopy of AGN candidates in the COSMOS field

Jonathan R. Trump, Christopher D Impey, Patrick J. McCarthy, Martin Elvis, John P. Huchra, Marcella Brusa, Gunther Hasinger, Eva Schinnerer, Peter Capak, Simon J. Lilly, Nick Z. Scoville

Research output: Contribution to journalArticle

95 Scopus citations


We present spectroscopic redshifts for the first 466 X-ray- and radio-selected AGN targets in the 2 deg 2 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 i AB = 24, although the yield is >90% for i AB < 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.

Original languageEnglish (US)
Pages (from-to)383-395
Number of pages13
JournalAstrophysical Journal, Supplement Series
Issue number1
Publication statusPublished - 2007



  • Galaxies: active
  • Quasars: general
  • Surveys

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

Trump, J. R., Impey, C. D., McCarthy, P. J., Elvis, M., Huchra, J. P., Brusa, M., ... Scoville, N. Z. (2007). Magellan spectroscopy of AGN candidates in the COSMOS field. Astrophysical Journal, Supplement Series, 172(1), 383-395.