Unveiling the origin of the radio emission in radio-quiet quasars

Abstract

The origin of the radio emission in radio-quiet quasars (RQQs) has been a matter of debate for a long time. It is not well understood whether the emission is caused by star formation in the host galaxy or by black hole activity of the active galactic nuclei (AGN). We shed some light on these questions using the Very Long Baseline Interferometry (VLBI) technique to search for RQQs in the field of the Cosmological Evolution Survey (COSMOS). The extensive multi-wavelength coverage of the field (from radio to X-rays) was used to classify RQQs, and the milli-arcsecond resolution of VLBI provides a direct way to identify AGNs. In a sample of 18 RQQs we detected 3 using the Very Long Baseline Array (VLBA) at 1.4 GHz. In this letter we report for the first time on a sample of RQQs with a measured lower limit on the fraction of radio emission coming from the AGN, thus demonstrating that the radio emission of at least some RQQs is dominated by an AGN.

arXiv comment4 pages, letter to the editor, accepted for publication in A&A

References in corpus (30)

• Mid-Infrared Selection of AGN with the Wide-Field Infrared Survey Explorer. I. Characterizing WISE-Selected AGN in COSMOS
• The First Release COSMOS Optical and Near-IR Data and Catalog
• Identifying Luminous AGN in Deep Surveys: Revised IRAC Selection Criteria
• Quasars, their host galaxies, and their central black holes
• On the Estimation of Confidence Intervals for Binomial Population Proportions in Astronomy: The Simplicity and Superiority of the Bayesian Approach
• The Chandra COSMOS Survey, I: Overview and Point Source Catalog
• A Catalog of Broad Absorption Line Quasars from the Sloan Digital Sky Survey Third Data Release
• Chandra Snapshot Observations of Low-Luminosity AGNs with a Compact Radio Source
• The Far- and Mid-Infrared/Radio Correlations in the Spitzer Extragalactic First Look Survey
• Search for TeV Gamma-ray Emission from GRB 100621A, an extremely bright GRB in X-rays, with H.E.S.S
• The Chandra COSMOS Survey: III. Optical and Infrared Identification of X-ray Point Sources
• The VLA-COSMOS Survey. IV. Deep Data and Joint Catalog
• The Half Million Quasars (HMQ) Catalogue
• The sub-mJy radio sky in the Extended Chandra Deep Field South: source population
• A new method to separate star forming from AGN galaxies at intermediate redshift: The submillijansky radio population in the VLA-COSMOS survey
• The COSMOS AGN Spectroscopic Survey I: XMM Counterparts
• The VLA Survey of the Chandra Deep Field South. V. Evolution and Luminosity Functions of sub-mJy radio sources and the issue of radio emission in radio-quiet AGN
• The radio properties of radio-quiet quasars
• The radio properties of radio-quiet quasars
• AGN and Starburst Radio Emission from Optically Selected QSOs
• Radio faint AGN: a tale of two populations
• Constraining the radio-loud fraction of quasars at z>5.5
• The Two-Component Radio Luminosity Function of QSOs: Star Formation and AGN
• Compton thick active galactic nuclei in Chandra surveys
• A comparison of the optical properties of radio-loud and radio-quiet quasars
• Disclosing the Radio Loudness Distribution Dichotomy in Quasars: An Unbiased Monte Carlo Approach Applied to the SDSS-FIRST Quasar Sample
• Eight-Dimensional Mid-Infrared/Optical Bayesian Quasar Selection
• Classifying Broad Absorption Line Quasars: Metrics, Issues and a New Catalogue Constructed from SDSS DR5
• High--cadence observations of spicular-type events on the Sun
• Radio Supernovae in the Great Survey Era

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• Active Galactic Nuclei: what's in a name?
• The Quest for Dual and Binary Supermassive Black Holes: A Multi-Messenger View
• The faint radio sky: radio astronomy becomes mainstream
• The VLA-COSMOS 3~GHz Large Project: AGN and host-galaxy properties out to z$\lesssim$6
• Radio Loud and Radio Quiet Quasars
• Galaxy Evolution in the Radio Band: The Role of Starforming Galaxies and Active Galactic Nuclei
• The Lockman Hole Project: new constraints on the sub-mJy source counts from a wide-area 1.4 GHz mosaic
• Extragalactic Radio Continuum Surveys and the Transformation of Radio Astronomy
• Evidence that the AGN dominates the radio emission in z ~ 1 radio-quiet quasars
• The radio loudness of SDSS quasars from the LOFAR Two-metre Sky Survey: ubiquitous jet activity and constraints on star formation
• The faint radio sky: VLBA observations of the COSMOS field
• Extremely deep 150 MHz source counts from the LoTSS Deep Fields
• BAT AGN Spectroscopic Survey -- XV: The High Frequency Radio Cores of Ultra-hard X-ray Selected AGN
• Strong lensing reveals jets in a sub-microJy radio quiet quasar
• Compact radio cores in radio-quiet AGNs
• Nowhere to Hide: Radio-faint AGN in the GOODS-N field. I. Initial catalogue and radio properties
• Does the evolution of the radio luminosity function of star-forming galaxies match that of the star-formation rate function?
• Completing the Census of AGN in GOODS-S/HUDF: New Ultra-Deep Radio Imaging and Predictions for JWST
• The eMERGE Survey I: Very Large Array 5.5 GHz observations of the GOODS-North Field
• VLBI Observations of a sample of Palomar-Green quasars I: parsec-scale morphology
• Interactions between the large-scale radio structures and the gas in a sample of optically selected type 2 quasars
• VLA and ALMA observations of the lensed radio-quiet quasar SDSS J0924+0219: a molecular structure in a 3 microJy radio source
• Placing LOFAR-detected quasars in CIV emission space: implications for winds, jets and star formation
• A novel Bayesian approach for decomposing the radio emission of quasars: I. Modelling the radio excess in red quasars
• A deep 1.4 GHz survey of the J1030 equatorial field: a new window on radio source populations across cosmic time
• LoTSS/HETDEX: Disentangling star formation and AGN activity in gravitationally-lensed radio-quiet quasars
• The optically-selected 1.4-GHz quasar luminosity function below 1 mJy
• How does the radio enhancement of broad absorption line quasars relate to colour and accretion rate?
• Kpc-scale Radio Structure in $z\sim 0.25$ Radio-Quiet QSOs
• The Quasar Feedback Survey: zooming into the origin of radio emission with e-MERLIN
• How are Red and Blue Quasars Different? The Radio Properties
• The optical luminosity function of LOFAR radio-selected quasars at $1.4\le z\le 5.0$ in the NDWFS-Boötes field
• What is the origin of the stacked radio emission in radio-undetected quasars?: Insights from a radio-infrared image stacking analysis
• Revealing faint compact radio jets at redshifts above 5 with very long baseline interferometry
• Exploring the radio spectral energy distribution of the ultraluminous radio-quiet quasar SDSS J0100+2802 at redshift 6.3
• High-Resolution Radio Observations of Five Optically Selected Type 2 Quasars
• Probing the Wind Component of Radio Emission in Luminous High-Redshift Quasars
• IC 630: Piercing the Veil of the Nuclear Gas
• Exploring the X-ray-radio connection for AGN via measurements of the multi-dimensional luminosity function
• Extragalactic radio surveys in the pre-Square Kilometre Array era
• Using strong lensing to understand the microJy radio emission in two radio quiet quasars at redshift 1.7