Sensitive Radio Survey of Obscured Quasar Candidates

Abstract

We study the radio properties of moderately obscured quasars over a range of redshifts to understand the role of radio activity in accretion using the Jansky Very Large Array (JVLA) at 6.0GHz and 1.4GHz. Our z~2.5 sample consists of optically-selected obscured quasar candidates, all of which are radio-quiet, with typical radio luminosities of $\nu L_{\nu }$[1.4 GHz] < $10^{40}$ erg s${}^{-1}$. Only a single source is individually detected in our deep (rms~10 $\mu$Jy) exposures. This population would not be identified by radio-based selection methods used for distinguishing dusty star-forming galaxies and obscured active nuclei. In our pilot A-array study of z~0.5 radio-quiet quasars, we spatially resolve four of five objects on scales ~ 5 kpc and find they have steep spectral indices. Therefore, radio emission in these sources could be due to jet-driven or radiatively driven bubbles interacting with interstellar material on the scale of the host galaxy. Finally, we also study the population of ~ 200 faint (~40 $\mu$Jy - 40 mJy) radio sources observed over ~ 120 arcmin${}^2$ of our data. 60% of these detections are matched in the SDSS and/or WISE and are, in roughly equal shares, active nuclei at a broad range of redshifts, passive galaxies with no other signs of nuclear activity and IR-bright but optically faint sources. Spectroscopically or photometrically confirmed star-forming galaxies constitute only a small minority of the matches. Such sensitive radio surveys allow us to address important questions of AGN evolution and evaluate the AGN contribution to the radio-quiet sky.

18 pages, submitted to MNRAS

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Cited by in corpus (9)

• Prevalence of radio jets associated with galactic outflows and feedback from quasars
• Extremely Red Quasars in BOSS
• Winds as the origin of radio emission in $z=2.5$ radio-quiet extremely red quasars
• The Quasar Feedback Survey: Discovering hidden Radio-AGN and their connection to the host galaxy ionised gas
• Host galaxies of high-redshift extremely red and obscured quasars
• Extreme ionised outflows are more common when the radio emission is compact in AGN host galaxies
• The Role of Major Mergers and Nuclear Star Formation in Nearby Obscured Quasars
• LoTSS/HETDEX: Disentangling star formation and AGN activity in gravitationally-lensed radio-quiet quasars
• The impact of low luminosity AGN on their host galaxies: A radio and optical investigation of the kpc-scale outflow in MaNGA 1-166919