LOFAR-Boötes: Properties of high- and low-excitation radio galaxies at $0.5<z<2.0$

Abstract

This paper presents a study of the redshift evolution of radio-loud active galactic nuclei (AGN) as a function of the properties of their galaxy hosts in the Boötes field. To achieve this we match low-frequency radio sources from deep $150$-MHz LOFAR observations to an $I$-band-selected catalogue of galaxies, for which we have derived photometric redshifts, stellar masses and rest-frame colours. We present spectral energy distribution (SED) fitting to determine the mid-infrared AGN contribution for the radio sources and use this information to classify them as High- versus Low-Excitation Radio Galaxies (HERGs and LERGs) or Star-Forming galaxies. Based on these classifications we construct luminosity functions for the separate redshift ranges going out to $z=2$. From the matched radio-optical catalogues, we select a sub-sample of $624$ high power ($P_{150\mathrm{MHz}}>10^{25}$ W Hz${}^{-1}$) radio sources between $0.5\le z<2$. For this sample, we study the fraction of galaxies hosting HERGs and LERGs as a function of stellar mass and host galaxy colour. The fraction of HERGs increases with redshift, as does the fraction of sources in galaxies with lower stellar masses. We find that the fraction of galaxies that host LERGs is a strong function of stellar mass as it is in the local Universe. This, combined with the strong negative evolution of the LERG luminosity functions over this redshift range, is consistent with LERGs being fuelled by hot gas in quiescent galaxies.

25 pages, 21 figures, accepted for publication in MNRAS

References in corpus (25)

• EAZY: A Fast, Public Photometric Redshift Code
• The Co-Evolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe
• COSMOS Photometric Redshifts with 30-bands for 2-deg2
• An ultra-deep near-infrared spectrum of a compact quiescent galaxy at z=2.2
• The LOFAR Two-metre Sky Survey - I. Survey Description and Preliminary Data Release
• Hot and cold gas accretion and feedback in radio-loud active galaxies
• Photometric redshift and classification for the XMM-COSMOS sources
• Radio sources in the 6dFGS: Local luminosity functions at 1.4 GHz for star-forming galaxies and radio-loud AGN
• On the prevalence of radio-loud AGN in brightest cluster galaxies: implications for AGN heating of cooling flows
• AGN-controlled cooling in elliptical galaxies
• The Massive Hosts of Radio Galaxies Across Cosmic Time
• The Spitzer Deep, Wide-Field Survey
• The X-ray nuclei of intermediate-redshift radio sources
• Photometric redshifts in the SWIRE Survey
• LOFAR/H-ATLAS: A deep low-frequency survey of the Herschel-ATLAS North Galactic Pole field
• Photometric Redshifts in the IRAC Shallow Survey
• Spitzer Reveals Hidden Quasar Nuclei in Some Powerful FR II Radio Galaxies
• A Public, K-Selected, Optical-to-Near-Infrared Catalog of the Extended Chandra Deep Field South (ECDFS) from the MUltiwavelength Survey by Yale-Chile (MUSYC)
• The cosmic evolution of radio-AGN feedback to z=1
• Radiative pressure feedback by a quasar in a galactic bulge
• The triggering probability of radio-loud AGN: A comparison of high and low excitation radio galaxies in hosts of different colors
• Photometric redshifts for the next generation of deep radio continuum surveys - I: Template fitting
• Radio-AGN Feedback: When the Little Ones were Monsters
• Black-hole masses, accretion rates and hot- and cold-mode accretion in radio galaxies at z~1
• The WEAVE-LOFAR Survey

Cited by in corpus (3)

• Revisiting the Fanaroff-Riley dichotomy and radio-galaxy morphology with the LOFAR Two-Metre Sky Survey (LoTSS)
• The XXL Survey: XXXVI. Evolution and black hole feedback of high-excitation and low-excitation radio galaxies in XXL-S
• Constraining the Active Galactic Nucleus and Starburst Properties of the IR-luminous Quasar Host Galaxy APM 08279+5255 at Redshift 4 with SOFIA