Volume 551, March 2013
|Number of page(s)||14|
|Section||Cosmology (including clusters of galaxies)|
|Published online||14 February 2013|
Luminosity function from dedicated SDSS-III and MMT data of quasars in 0.7 < z < 4.0 selected with a new approach
1 CEACentre de Saclay, Irfu/SPP, 91191 Gif-sur-Yvette, France
2 Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071, USA
3 Max-Planck-Institut fürAstronomie, Königstuhl 17, 69117 Heidelberg, Germany
4 Université Paris 6, Institut d’Astrophysique de Paris, CNRS UMR 7095, 98bis Bd Arago, 75014 Paris, France
5 Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
6 APC, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
7 Steward Observatory, University of Arizona, Tucson, AZ 85721, USA
8 National Optical Astronomy Observatory, Tucson, AZ 85726-6732, USA
9 Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
10 Apache Point Observatory, PO Box 59, Sunspot, NM 88349-0059, USA
11 University of Utah, Dept. of Physics & Astronomy, 115 S 1400 E, Salt Lake City, UT 84112, USA
12 Department of Astronomy, University of Florida, 211 Bryant Space Science Center, PO Box 112055, Gainesville, FL 32611, USA
13 Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
14 Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802, USA
15 Brookhaven National Laboratory, Bldg 510, Upton, NY 11973, USA
16 Center for Cosmology and Particle Physics, New York University, New York, NY 10003, USA
Received: 13 September 2012
Accepted: 23 December 2012
We present a measurement of the quasar luminosity function in the range 0.68 < z < 4 down to extinction corrected magnitude gdered = 22.5, using a simple and well understood target selection technique based on the time-variability of quasars. The completeness of our sample was derived directly from a control sample of quasars, without requiring complex simulations of quasar light-curves or colors. A total of 1877 quasar spectra were obtained from dedicated programs on the Sloan telescope (as part of the SDSS-III/BOSS survey) and on the Multiple Mirror Telescope. They allowed us to derive the quasar luminosity function. It agrees well with results previously published in the redshift range 0.68 < z < 2.6. Our deeper data allow us to extend the measurement to z = 4. We measured quasar densities to gdered < 22.5, obtaining 30 QSO per deg2 at z < 1, 99 QSO per deg2 for 1 < z < 2.15, and 47 QSO per deg2 at z > 2.15. Using pure luminosity evolution models, we fitted our LF measurements and predicted quasar number counts as a function of redshift and observed magnitude. These predictions are useful inputs for future cosmology surveys such as those relying on the observation of quasars to measure baryon acoustic oscillations.
Key words: quasars: general / dark energy / surveys
© ESO, 2013
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