Unveiling the weak radio quasar population at z $\ge$ 4

Abstract

We applied image stacking on empty-field Faint Images of the Radio Sky at Twenty-Centimeters (FIRST) survey maps centred on optically identified high-redshift quasars at $z\ge 4$ to uncover the hidden $\mu$Jy radio emission in these active galactic nuclei (AGN). The median stacking procedure for the full sample of $2229$ optically identified AGN uncovered an unresolved point source with an integrated flux density of 52$\mu$Jy, with a signal-to-noise ratio $\sim 10$. We co-added the individual image centre pixels to estimate the characteristic monochromatic radio power at $1.4$GHz considering various values for the radio spectral index, revealing a radio population with $P_{1.4GHz}\sim 10^{24}$W Hz${}^{-1}$. Assuming that the entire radio emission originates from star-forming (SF) activity in the nuclear region of the host galaxy, we obtained an upper limit on the characteristic star formation rate, $\sim 4200$M${}_{\odot }$yr${}^{-1}$. The angular resolution of FIRST images is insufficient to distinguish between the SF and AGN origin of radio emission at these redshifts. However, a comparison with properties of individual sources from the literature indicates that a mixed nature is likely. Future very long baseline interferometry radio observations and ultra-deep Square Kilometre Array surveys are expected to be sensitive enough to detect and resolve the central $1-10$kpc region in the host galaxies, and thus discriminate between SF and AGN related emission.

arXiv comment9 pages, 3 figures, 3 tables, accepted for publication in MNRAS

References in corpus (75)

• The Sloan Digital Sky Survey: Technical Summary
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way Galaxy, and Extra-Solar Planetary Systems
• Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
• The Dark Energy Survey: more than dark energy - an overview
• Radio Properties of Infrared Selected Galaxies in the IRAS 2 Jy Sample
• Estimating Star Formation Rates from Infrared and Radio Luminosities: The Origin of the Radio-Infrared Correlation
• The host galaxies of radio-loud AGN: mass dependencies, gas cooling and AGN feedback
• The Pan-STARRS1 Surveys
• The star formation history of mass-selected galaxies in the COSMOS field
• The Sloan Digital Sky Survey Quasar Catalog: twelfth data release
• Star Formation and Gas Kinematics of Quasar Host Galaxies at z~6: New insights from ALMA
• The VLA-COSMOS 3 GHz Large Project: Continuum data and source catalog release
• Star formation rate indicators in the Sloan Digital Sky Survey
• Quasar feedback and the origin of radio emission in radio-quiet quasars
• The Last of FIRST: The Final Catalog and Source Identifications
• Resolved Molecular Gas in a Quasar Host Galaxy at Redshift z=6.42
• The Sloan Digital Sky Survey quasar catalog: ninth data release
• Pah and Mid-IR Luminosities as Measures of Star-Formation Rate in Spitzer First Look Survey Galaxies
• On the origin of radio emission in radio quiet quasars
• Signals from the Noise: Image Stacking for Quasars in the FIRST Survey
• The Great Observatories All-Sky LIRG Survey: Comparison of Ultraviolet and Far-Infrared Properties
• Bright [CII] and dust emission in three z>6.6 quasar host galaxies observed by ALMA
• [CII] 158 $\mu$m Emission as a Star Formation Tracer
• High-excitation CO in a quasar host galaxy at z=6.42
• The VLA-COSMOS 3 GHz Large Project: Multiwavelength counterparts and the composition of the faint radio population
• The VLA-COSMOS 3~GHz Large Project: AGN and host-galaxy properties out to z$\lesssim$6
• The sub-mJy radio sky in the Extended Chandra Deep Field South: source population
• Star formation rate and dynamical mass of 10^8 solar mass black hole host galaxies at redshift 6
• The VLA-COSMOS 3~GHz Large Project: Cosmic evolution of radio AGN and implications for radio-mode feedback since z~5
• Redshift 6.4 host galaxies of 10^8 solar mass black holes: low star formation rate and dynamical mass
• The VLA 1.4GHz Survey of the Extended Chandra Deep Field South: Second Data Release
• AGN and Starburst Radio Emission from Optically Selected QSOs
• The VLA 1.4GHz Survey of the Extended Chandra Deep Field South: First Data Release
• Star formation in quasar hosts and the origin of radio emission in radio-quiet quasars
• Exploring the infrared/radio correlation at high redshift
• Aromatic Features in AGN: Star-Forming Infrared Luminosity Function of AGN Host Galaxies
• The cosmic evolution of radio-AGN feedback to z=1
• The compact, ~1 kpc host galaxy of a quasar at z=7.1
• Quasar host galaxy star formation activity from multicolour data
• New Insights on the QSO Radio-Loud/Radio-Quiet Dichotomy: SDSS Spectra in the Context of the 4D Eigenvector1 Parameter Space
• Probing the interstellar medium and star formation of the Most Luminous Quasar at z=6.3
• A comparison of the optical properties of radio-loud and radio-quiet quasars
• 400 pc Imaging of a Massive Quasar Host Galaxy at a Redshift of 6.6
• GAMA/WiggleZ: The 1.4GHz radio luminosity functions of high- and low-excitation radio galaxies and their redshift evolution to z=0.75
• Disclosing the Radio Loudness Distribution Dichotomy in Quasars: An Unbiased Monte Carlo Approach Applied to the SDSS-FIRST Quasar Sample
• Parsec-Scale Radio Emission from the Low-Luminosity Active Galactic Nucleus in the Dwarf Starburst Galaxy Henize 2-10
• Winds as the origin of radio emission in $z=2.5$ radio-quiet extremely red quasars
• LoTSS/HETDEX: Optical quasars I. Low-frequency radio properties of optically selected quasars
• Low-Luminosity AGNs at the Highest Resolution: Jets or Accretion Flows?
• What drives the radio slopes in radio quiet quasars?
• Wide-field VLBA Observations of the Chandra Deep Field South
• Ultraviolet-to-Far-Infrared Properties of Local Star-Forming Galaxies
• The prevalence of AGN feedback in massive galaxies at z~1
• Star Formation and ISM Properties in Host Galaxies of Three Far-infrared Luminous Quasars at $z\sim 6$
• Detecting Radio-AGN signatures in Red geysers
• Synchrotron Emission from Elliptical Galaxies Consequent to AGN outbursts
• The VLA-COSMOS 3 GHz Large Project: Star formation properties and radio luminosity functions of AGN with moderate-to-high radiative luminosities out to $z\sim 6$
• Very High Angular Resolution Science with the Square Kilometre Array
• A search for AGN in the most extreme UV-selected starbursts using the European VLBI Network
• The Mid-infrared Emission of Narrow-Line Active Galactic Nuclei: Star-Formation, Nuclear Activity and two populations revealed by WISE
• Radio Detection of Radio-Quiet Galaxies
• Radio source stacking and the infrared / radio correlation at microJy flux densities
• Star-Formation in Low Radio Luminosity AGN from the Sloan Digital Sky Survey
• The Star Formation Reference Survey III: A Multi-wavelength View of Star Formation in Nearby Galaxies
• Four dual AGN candidates observed with the VLBA
• Radio galaxies in ZFOURGE/NMBS: no difference in the properties of massive galaxies with and without radio-AGN out to z = 2.25
• The Role of Host Galaxy for the Environmental Dependence of Active Nuclei in Local Galaxies
• The host galaxies of radio-quiet quasars at 0.5<z<1.0
• Radio-quiet objects in the 2QZ survey
• A Search for Active Galactic Nuclei in Sc Galaxies with H II Spectra
• The radio luminosity function of radio-loud quasars from the 7C Redshift Survey
• Milli-arcsecond imaging of the radio emission from the quasar with the most massive black hole at reionization
• Is the observed high-frequency radio luminosity distribution of QSOs bimodal?
• Radio stacking reveals evidence for star formation in the host galaxies of X-ray selected active galactic nuclei at z<1

Cited by in corpus (8)

• Deep silence: radio properties of little red dots
• VLBI observations of VIK J2318-3113, a quasar at z = 6.44
• VALES VI: ISM enrichment in star-forming galaxies up to z$\sim$0.2 using ${}^{12}$CO(1-0), ${}^{13}$CO(1-0) and C${}^{18}$O(1-0) line luminosity ratios
• Radio emission from dust-obscured galaxies
• What is the origin of the stacked radio emission in radio-undetected quasars?: Insights from a radio-infrared image stacking analysis
• A method for checking high-redshift identification of radio AGNs
• High-resolution Imaging of Two Radio Quasars at the End of the Reionization Epoch
• Milliarcsecond-scale radio structure of the most distant BL Lac object candidate at redshift 6.57