Exploring the Connection between UV/Optical Variations and Radio Emission in Radio-Quiet Quasars: Clues on Radio Emission Origin

Abstract

The radio emission in radio-quiet quasars (RQQs) has been a long mystery and its physical origin remains unclear. In a previous work we find UV/optical more variable quasars have stronger X-ray emission, indicating a link between disc turbulence and X-ray corona heating. In this work, for the first time, we investigate the relation between UV/optical variability and the radio emission in RQQs selected from SDSS stripe 82 and FIRST radio survey. We median stack the FIRST images and detect clear signals from RQQs in the co-added images of individually radio non-detected sources. Controlling the effects of other parameters, including redshift, black hole mass, bolometric luminosity and Eddington ratio, we find more variable RQQs, which are known to be X-ray relatively brighter, show tentatively weaker radio emission, contrary to the linear X-ray/radio correlation if the radio emission is from or driven by the corona. The discovery also suggests that if the radio emission in RQQs is driven by AGN activity (such as weak jet), the underlying driving process is independent to the disc turbulence which drives UV/optical variability and probably also corona heating. Alternatively, the radio emission could be due to star formation in the host galaxies.

arXiv comment8 pages, 7 figures, accepted by MNRAS

References in corpus (56)

• The NumPy array: a structure for efficient numerical computation
• LOFAR: The LOw-Frequency ARray
• A Catalog of Quasar Properties from SDSS DR7
• Relativistic Jets in Active Galactic Nuclei
• Are the Variations in Quasar Optical Flux Driven by Thermal Fluctuations?
• The LOFAR Two-metre Sky Survey - I. Survey Description and Preliminary Data Release
• Active Galactic Nuclei: what's in a name?
• The star formation history of mass-selected galaxies in the COSMOS field
• Optical and Radio Properties of Extragalactic Sources Observed by the FIRST and SDSS Surveys
• The XMM-Newton serendipitous survey IX. The fourth XMM-Newton serendipitous source catalogue
• Quasar feedback and the origin of radio emission in radio-quiet quasars
• The Last of FIRST: The Final Catalog and Source Identifications
• A Description of Quasar Variability Measured Using Repeated SDSS and POSS Imaging
• Narrow-line region gas kinematics of 24,264 optically-selected AGN: the radio connection
• Radio galaxies and feedback from AGN jets
• On the origin of radio emission in radio quiet quasars
• Signals from the Noise: Image Stacking for Quasars in the FIRST Survey
• The faint radio sky: radio astronomy becomes mainstream
• The X-ray and Radio Connection in Low-luminosity Active Nuclei
• Radio Loud and Radio Quiet Quasars
• VLBA Imaging of Central Engines in Radio Quiet Quasars
• The radio properties of radio-quiet quasars
• The radio properties of radio-quiet quasars
• The radio structure of radio-quiet quasars
• Star formation in quasar hosts and the origin of radio emission in radio-quiet quasars
• On the two main classes of Active Galactic Nuclei
• The optically-powerful quasar E1821+643 is associated with a 300-kpc scale FRI radio structure
• The VLA-COSMOS Perspective on the IR-Radio Relation. I. New Constraints on Selection Biases and the Non-Evolution of the IR/Radio Properties of Star Forming and AGN Galaxies at Intermediate and High Redshift
• The central engines of radio-quiet quasars
• The correlations between optical variability and physical parameters of quasars in SDSS Stripe 82
• High-resolution VLA Imaging of SDSS Stripe 82 at 1.4 GHz
• Star formation properties of sub-mJy radio sources
• AGN Coronal Emission models I. The Predicted Radio Emission
• AGN Populations in Large Volume X-ray Surveys: Photometric Redshifts and Population Types found in the Stripe 82X Survey
• 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
• The 1.4 GHz radio properties of hard X-ray selected AGN
• Sub-parsec radio cores in nearby Seyfert galaxies
• Evidence that the AGN dominates the radio emission in z ~ 1 radio-quiet quasars
• A relativistic jet in the radio-quiet quasar PG1407+263
• The radio loudness of SDSS quasars from the LOFAR Two-metre Sky Survey: ubiquitous jet activity and constraints on star formation
• Detection of Coronal Magnetic Activity in Nearby Active Supermassive Black Holes
• EUCLIA - Exploring the UV/optical continuum lag in active galactic nuclei. I. a model without light echoing
• The mm-wave compact component of AGN
• High-resolution radio observations of Seyfert galaxies in the extended 12-micron sample - II. The properties of compact radio components
• Star-formation in the central kpc of the starburst/LINER galaxy NGC1614
• BAT AGN Spectroscopic Survey -- XV: The High Frequency Radio Cores of Ultra-hard X-ray Selected AGN
• Simulating the timescale dependent color variation in quasars with a revised inhomogeneous disk model
• The radio emission from Active Galactic Nuclei
• Radio source stacking and the infrared / radio correlation at microJy flux densities
• The obstructed jet in Mrk 231
• Multiwavelength scaling relations for nuclei of Seyfert galaxies
• An intrinsic link between long-term UV/optical variations and X-ray loudness in quasars
• New Clues to Jet Launching: The inner disks in radio loud quasars may be more stable
• More variable quasars have stronger emission lines
• The composite X-ray spectra of radio-loud and radio-quiet SDSS quasars

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