The space density of high-redshift QSOs in the Great Observatories Origins Deep Survey

S. Cristiani, D. M. Alexander, F. Bauer, W. N. Brandt, E. T. Chatzichristou, F. Fontanot, A. Grazian, A. Koekemoer, R. A. Lucas, P. Monaco, M. Nonino, P. Padovani, D. Stern, P. Tozzi, E. Treister, C. M. Urry, E. Vanzella

Research output: Contribution to journalReview articlepeer-review

56 Scopus citations


We present a sample of 17 high-redshift (3.5 ≲ z ≲ 5.2) quasi-stellar object (QSO) candidates in the 320 arcmin2 area of the Great Observatories Origins Deep Survey, selected in the magnitude range 22.45 < z850 < 25.25 using deep imaging with the Advanced Camera for Surveys on board the Hubble Space Telescope and the Advanced CCD Imaging Spectrometer on board the Chandra X-Ray Observatory. On the basis of seven spectroscopic and 10 photometric redshifts, we estimate that the final sample will contain between two and four QSOs with 4 < z < 5.2. A dearth of high-redshift moderate-luminosity (M145 ≃ -23) QSOs is observed with respect to predictions based on (1) the extrapolation of the z ∼ 2.7 luminosity function (LF), according to a pure luminosity evolution calibrated by the results of the Sloan Digital Sky Survey, and (2) a constant universal efficiency in the formation of supermassive black holes (SMBHs) in dark matter halos. Evidence is gathered in favor of a density evolution of the LF at high redshift and of a suppression of the formation or feeding of SMBHs in low-mass halos.

Original languageEnglish (US)
Pages (from-to)L119-L122
JournalAstrophysical Journal
Issue number2 II
StatePublished - Jan 10 2004

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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