Faint radio-loud quasars: clues to their evolution

Abstract

The quasar sample selected by cross-correlating the FIRST and the 2dF Quasar Redshift Surveys allows us to explore, for the first time, the faint end of the radio and optical luminosity functions up to z = 2.2. We find indications (~3 σ) of a negative evolution for these faint sources at z > 1.8, both in radio and optical bands. This corresponds to a decrement in the space density of faint quasars of about a factor 2 at z=2.2 and confirms the presence of a differential evolution for the population of radio-active quasars. The faint end of both luminosity functions flattens and the comparison with the (optical) number density of the whole quasar population supports a dependence of the fraction of radio detected quasars on the optical luminosity. A progressive decrease in the fraction of quasars in the whole radio source population can be consistently accounted for within the `receding torus' scenario. The population of low luminosity quasars, which the FIRST-2dF detects, appears to depart from the `classical' scheme for radio-loud quasars.

arXiv comment11 pages, 7 figures, accepted for publication in MNRAS

References in corpus (26)

• Unified Schemes for Radio-Loud Active Galactic Nuclei
• The Demography of Massive Dark Objects in Galaxy Centres
• Cosmological Evolution of the Hard X-ray AGN Luminosity Function and the Origin of the Hard X-ray Background
• Beyond the Bulge: a Fundamental Relation Between Supermassive Black Holes and Dark Matter Halos
• The 2dF QSO Redshift Survey - I. The Optical QSO Luminosity Function
• On the black hole - bulge mass relation in active and inactive galaxies
• The Microwave Anisotropy Probe (MAP) Mission
• The emission line - radio correlation for radio sources using the 7C Redshift Survey
• High-Redshift Quasars Found in Sloan Digital Sky Survey Commissioning Data IV: Luminosity Function from the Fall Equatorial Stripe Sampl
• The radio luminosity function from the low-frequency 3CRR, 6CE & 7CRS complete samples
• Composite Spectra from the FIRST Bright Quasar Survey
• Extragalactic radio source evolution under the dual-population unification scheme
• The optically-powerful quasar E1821+643 is associated with a 300-kpc scale FRI radio structure
• The quasar fraction in low-frequency selected complete samples and implications for unified schemes
• Is there a Dichotomy in the Radio Loudness Distribution of Quasars?
• Variance and Skewness in the FIRST survey
• A comparison of the optical properties of radio-loud and radio-quiet quasars
• The Radio Loud / Radio Quiet dichotomy: news from the 2dF QSO Redshift Survey
• A new look at the isotropy of narrow line emission in extragalactic radio sources
• On the redshift cut-off for steep-spectrum radio sources
• On the redshift cut-off for flat-spectrum radio sources
• The cosmic evolution of low-luminosity radio sources from the SDSS DR1
• Gemini imaging of QSO host galaxies at z~2
• Decline of the space density of quasars between z=2 and z=4
• Optical identifications of $\sim 4000$ radio sources at the 1 mJy level
• Radio Properties of FIRST Radio Sources at 1 mJy

Cited by in corpus (25)

• An Observational Determination of the Bolometric Quasar Luminosity Function
• Absorption Properties and Evolution of Active Galactic Nuclei
• A synthesis model for AGN evolution: supermassive black holes growth and feedback modes
• Radio and Millimeter Continuum Surveys and their Astrophysical Implications
• Accreting SMBHs in the COSMOS field and the connection to their host galaxies
• The VVDS type-1 AGN sample: The faint end of the luminosity function
• Low redshift AGN in the Hamburg/ESO Survey: II. The active black hole mass function and the distribution function of Eddington ratios
• The Evolution in the Faint-End Slope of the Quasar Luminosity Function
• A model for the cosmological evolution of low frequency radio sources
• Double Lobed Radio Quasars from the Sloan Digital Sky Survey
• The role of black hole mass in quasar radio activity
• AGN-Host Galaxy Connection: Morphology and Colours of X-ray Selected AGN at z < 2
• The Optical-Radio Mapping: the kinetic efficiency of Radio-Loud AGNs
• Faint-end Quasar Luminosity Functions from Cosmological Hydrodynamic Simulations
• The RASS--6dFGS catalogue: a sample of X-ray selected AGN from the 6dF Galaxy Survey
• On the Evolution of the Cores of Radio Sources and Their Extended Radio Emission
• Early Black Holes in Cosmological Simulations: Luminosity Functions and Clustering Behaviour
• Photometric Catalogue of Quasars and Other Point Sources in the Sloan Digital Sky Survey
• The impact from survey depth and resolution on the morphological classification of galaxies
• On the radio properties of the highest redshift quasars
• The optically-selected 1.4-GHz quasar luminosity function below 1 mJy
• Evolution of luminosity function and obscuration of AGN: connecting X-ray and Infrared
• Cosmological evolution of compact AGN at 15 GHz
• The optical luminosity function of LOFAR radio-selected quasars at $1.4\le z\le 5.0$ in the NDWFS-Boötes field
• X-ray luminosity functions of different morphological and X-ray type AGN populations