Counting quasar--radio source pairs to derive the millijansky radio luminosity function and clustering strength to z=3.5

Abstract

We apply a cross-correlation technique to infer the $S>3$mJy radio luminosity function (RLF) from the NRAO VLA sky survey (NVSS) to $z\sim 3.5$. We measure $\Sigma$ the over density of radio sources around spectroscopically confirmed quasars. $\Sigma$ is related to the space density of radio sources at the distance of the quasars and the clustering strength between the two samples, hence knowledge of one constrains the other. Under simple assumptions we find $\Phi \propto (1+z{)}^{3.7\pm 0.7}$ out to $z\sim 2$. Above this redshift the evolution slows and we constrain the evolution exponent to $<1.01$ ($2\sigma$). This behaviour is almost identical to that found by previous authors for the bright end of the RLF potentially indicating that we are looking at the same population. This suggests that the NVSS is dominated by a single population; most likely radio sources associated with high-excitation cold-mode accretion. Inversely, by adopting a previously modelled RLF we can constrain the clustering of high-redshift radio sources and find a clustering strength consistent with $r_0=15.0\pm 2.5$ Mpc up to $z\sim 3.5$. This is inconsistent with quasars at low redshift and some measurements of the clustering of bright FRII sources. This behaviour is more consistent with the clustering of lower luminosity radio galaxies in the local universe. Our results indicate that the high-excitation systems dominating our sample are hosted in the most massive galaxies at all redshifts sampled.

9 pages, 9 figures, accepted for publication in MNRAS

References in corpus (17)

• Hot and cold gas accretion and feedback in radio-loud active galaxies
• Radio sources in the 6dFGS: Local luminosity functions at 1.4 GHz for star-forming galaxies and radio-loud AGN
• Calibrating Redshift Distributions Beyond Spectroscopic Limits with Cross-Correlations
• The Sloan Digital Sky Survey quasar catalog: tenth data release
• The 2dF-SDSS LRG and QSO Survey: QSO clustering and the L-z degeneracy
• Radio imaging of the Subaru/XMM-Newton Deep Field - I. The 100-microJy catalogue, optical identifications, and the nature of the faint radio source population
• The Star Formation History of the Universe as Revealed by Deep Radio Observations
• Methods for Rapidly Processing Angular Masks of Next-Generation Galaxy Surveys
• The 2dF-SDSS LRG and QSO (2SLAQ) Luminous Red Galaxy Survey
• The 2dF-SDSS LRG and QSO survey: Evolution of the Luminosity Function of Luminous Red Galaxies to z=0.6
• The 2dF-SDSS LRG and QSO survey: evolution of the clustering of luminous red galaxies since z = 0.6
• The cosmic evolution of radio-AGN feedback to z=1
• Radio galaxies in the 2SLAQ Luminous Red Galaxy Survey: I. The evolution of low-power radio galaxies to z~0.7
• Reconstructing Redshift Distributions with Cross-Correlations: Tests and an Optimized Recipe
• The clustering of radio galaxies at z~0.55 from the 2SLAQ LRG survey
• Galaxy and Mass Assembly (GAMA): The evolution of bias in the radio source population to z ~ 1.5
• Evolution in the bias of faint radio sources to z ~ 2.2

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