The 2dF QSO Redshift Survey - XII. The spectroscopic catalogue and luminosity function

Abstract

We present the final catalogue of the 2dF QSO Redshift Survey (2QZ), based on Anglo‐Australian Telescope 2dF spectroscopic observations of 44 576 colour‐selected (ubJr) objects with 18.25 < bJ < 20.85 selected from automated plate measurement scans of UK Schmidt Telescope (UKST) photographic plates. The 2QZ comprises 23 338 quasi‐stellar objects (QSOs), 12 292 galactic stars (including 2071 white dwarfs) and 4558 compact narrow emission‐line galaxies. We obtained a reliable spectroscopic identification for 86 per cent of objects observed with 2dF. We also report on the 6dF QSO Redshift Survey (6QZ), based on UKST 6dF observations of 1564 brighter(16 < bJ < 18.25) sources selected from the same photographic input catalogue. In total, we identified 322 QSOs spectroscopically in the 6QZ. The completed 2QZ is, by more than a factor of 50, the largest homogeneous QSO catalogue ever constructed at these faint limits (bJ < 20.85) and high QSO surface densities (35 QSOs deg−2). As such, it represents an important resource in the study of the Universe at moderate‐to‐high redshifts. As an example of the results possible with the 2QZ, we also present our most recent analysis of the optical QSO luminosity function and its cosmological evolution with redshift. For a flat, Ωm= 0.3 and ΩΛ= 0.7, universe, we find that a double power law with luminosity evolution that is exponential in look‐back time, τ, of the form L b J*(z)∝ e6.15τ, equivalent to an e‐folding time of 2 Gyr, provides an acceptable fit to the redshift dependence of the QSO LF over the range 0.4 < z < 2.1 and M b J < −22.5. Evolution described by a quadratic in redshift is also an acceptable fit, with L b J*(z)∝ 10 1.39italicz−0.29italicz 2.

The cosmic growth of the active black hole population at 1 <z <2 in zCOSMOS, VVDS and SDSS

“…(B3) The normalization of the AGN LF is determined by the ratio of the number of observed AGN to the number of AGN expected from the best-fitting model, Φ * M = N obs /N mod . Over the restricted redshift range we are probing (1.1 < z < 2.1), the redshift evolution in the AGN LF can be well approximated with a simple pure luminosity evolution (PLE) model (Croom et al 2004;Ross et al 2013). We follow Boyle et al (2000) by modelling the redshift evolution in the break of 1.6 <z <2.1 Figure B1.…”

Clustering of intermediate redshift quasars using the final SDSS III-BOSS sample

“…where k1 = 1.39 and k2 = −0.29 for z 3 and k1 = 1.22 and k2 = −0.23 for z 3 (from Croom et al 2004, modified by Croton et al 2006). Quasars at higher redshift are fainter, and fainter quasars have larger flux uncertainties which translate into imprecision in measured colours.…”

A unifying evolutionary framework for infrared-selected obscured and unobscured quasar host haloes

“…Lacy et al 2004;Treister et al 2004;Stern et al 2005;Hickox et al 2007Hickox et al , 2009Hickox et al , 2011Stern et al 2012;Hainline et al 2014;DiPompeo et al 2014b;Hickox et al 2014;Lacy et al 2015;DiPompeo et al 2015; that has historically been dominated by optically detected unobscured systems (e.g. Croom et al 2004Croom et al , 2005Richards et al 2006a,b;Myers et al 2007;Croom et al 2009;Ross et al 2009;Shen et al 2009;Bonoli et al 2009;Eftekharzadeh et al 2015). This has resulted in tension between the prevailing paradigms that attempt to explain the physical origin of observational quasar subclasses.…”