Radio Variability of Radio Quiet and Radio Loud Quasars

Abstract

The majority of quasars are weak in their radio emission, with flux densities comparable to those in the optical, and energies far lower. A small fraction, about 10%, are hundreds to thousands of times stronger in the radio. Conventional wisdom holds that there are two classes of quasars, the radio quiets and radio louds, with a deficit of sources having intermediate power. Are there really two separate populations, and if so, is the physics of the radio emission fundamentally different between them? This paper addresses the second question, through a study of radio variability across the full range of radio power, from quiet to loud. The basic findings are that the root mean square amplitude of variability is independent of radio luminosity or radio-to-optical flux density ratio, and that fractionally large variations can occur on timescales of months or less in both radio quiet and radio loud quasars. Combining this with similarities in other indicators, such as radio spectral index and the presence of VLBI-scale components, leads to the suggestion that the physics of radio emission in the inner regions of all quasars is essentially the same, involving a compact, partially opaque core together with a beamed jet.

32 pages, 9 figures. Astrophysical Journal, in press

References in corpus (6)

• Quasars, their host galaxies, and their central black holes
• Optical and Radio Properties of Extragalactic Sources Observed by the FIRST and SDSS Surveys
• The Black Hole-Bulge Relationship in QSOs
• The optically-powerful quasar E1821+643 is associated with a 300-kpc scale FRI radio structure
• The FIRST Bright Quasar Survey III. The South Galactic Cap
• A relativistic jet in the radio-quiet quasar PG1407+263

Cited by in corpus (99)

• Relativistic Jets in Active Galactic Nuclei
• The New Generation Atlas of Quasar Spectral Energy Distributions from Radio to X-rays
• On the origin of radio emission in radio quiet quasars
• A Unified Catalog of Radio Objects Detected by NVSS, FIRST, WENSS, GB6, and SDSS
• Prevalence of radio jets associated with galactic outflows and feedback from quasars
• X-ray Insights into the Nature of PHL 1811 Analogs and Weak Emission-Line Quasars: Unification with a Geometrically Thick Accretion Disk?
• Thermal Emission from Warm Dust in the Most Distant Quasars
• Radio Loud and Radio Quiet Quasars
• VLBA Imaging of Central Engines in Radio Quiet Quasars
• AGN and Starburst Radio Emission from Optically Selected QSOs
• The radio structure of radio-quiet quasars
• Galaxy Evolution in the Radio Band: The Role of Starforming Galaxies and Active Galactic Nuclei
• Quasars That Have Transitioned from Radio-quiet to Radio-loud on Decadal Timescales Revealed by VLASS and FIRST
• X-ray and Multiwavelength Insights into the Nature of Weak Emission-Line Quasars at Low Redshift
• Radio Variability in Seyfert Nuclei
• A Full Year's Chandra Exposure on SDSS Quasars from the Chandra Multiwavelength Project
• Fundamental differences in the radio properties of red and blue quasars: evolution strongly favoured over orientation
• AGN Coronal Emission models I. The Predicted Radio Emission
• A survey for transients and variables with the Murchison Widefield Array 32-tile prototype at 154 MHz
• What drives the radio slopes in radio quiet quasars?
• Optical and Near-IR long-term monitoring of NGC3783 and MR2251-178: evidence for variable near-IR emission from thin accretion discs
• VLBA Identification of the Milliarcsecond Active Nucleus in the Seyfert Galaxy NGC 4151
• Discovery of Millimeter-Wave Excess Emission in Radio-Quiet Active Galactic Nuclei
• Correlations of Quasar Optical Spectra with Radio Morphology
• Search for ionized jets towards high-mass young stellar objects
• Mean and Extreme Radio Properties of Quasars and the Origin of Radio Emission
• High Radio Frequency Properties and Variability of Brightest Cluster Galaxies
• The Radio Properties of Type 2 Quasars
• The Size of the Radio-Emitting Region in Low-luminosity Active Galactic Nuclei
• Observations of radio-quiet quasars at 10mas resolution by use of gravitational lensing
• Infrared and hard X-ray diagnostics of AGN identification from the Swift/BAT and AKARI all-sky surveys
• Strong lensing reveals jets in a sub-microJy radio quiet quasar
• Radio spectra and polarisation properties of a bright sample of Radio-Loud Broad Absorption Line Quasars
• Is there really a dichotomy in AGN jet power?
• Exploratory X-ray Monitoring of Luminous Radio-Quiet Quasars at High Redshift: Initial Results
• AGN Coronae Through A Jet Perspective
• Observations and properties of candidate high frequency GPS radio sources in the AT20G survey
• Decoding signatures of extra dimensions and estimating spin of quasars from the continuum spectrum
• Probing the origin of low-frequency radio emission in PG quasars with the uGMRT -- I
• Possible Origin of Radio Emission from Nonthermal Electrons in Hot Accretion Flows for Low-Luminosity Active Galactic Nuclei
• The nature of the intranight variability of radio-quiet quasars
• Evidence for a population of beamed radio intermediate quasars
• A search for variable and transient radio sources in the extended Chandra Deep Field South at 5.5 GHz
• Discovery of Radio Emission from the Quasar SDSS J1536+0441, a Candidate Binary Black-Hole System
• Detection of a Parsec-Scale Jet in a Radio-Quiet Narrow-Line Seyfert 1 Galaxy with Highly Accreting Supermassive Black Hole
• VLBI Observations of a sample of Palomar-Green quasars I: parsec-scale morphology
• The precious set of radio-optical reference frame objects in the light of Gaia DR2 data
• Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power
• A Sample of Candidate Radio Stars in FIRST and SDSS
• Enhanced Star Formation Efficiency in the Central Regions of Nearby Quasars Hosts
• The PG-RQS survey. Building the radio spectral distribution of radio-quiet quasars. I. The 45-GHz data
• Implications of Einstein-Maxwell dilaton-axion gravity from the black hole continuum spectrum
• Intra-Night Optical monitoring of three γ-ray detected Narrow-line Seyfert 1 galaxies
• A Method to Measure the Unbiased Decorrelation Timescale of the AGN Variable Signal from Structure Functions
• The faintest radio source yet: EVLA observations of the gravitational lens SDSS J1004+4112
• VLBI detection of an AGN pair in the binary black hole candidate SDSS J1536+0441
• High Resolution Radio Astronomy Using Very Long Baseline Interferometry
• Simultaneous Millimeter-wave and X-ray monitoring of the Seyfert Galaxy NGC 7469
• Intranight Optical Variability of Radio-Quiet Weak Emission Line Quasars-III
• On the relation between hard X-ray photon index versus accretion rate for super-Eddington accreting quasars
• Daily variability at milli-arcsecond scales in the radio quiet NLSy1 Mrk 110
• Synchrotron radio emission in radio-quiet AGNs
• Radio constraints on the volume filling factors of AGN winds
• Hard-X-ray-selected Active Galactic Nuclei -- II. Spectral Energy Distributions in the 5-45 GHz domain
• Nuclear Infrared Spectral Energy Distribution of Type II Active Galactic Nuclei
• The radio dichotomy of active galactic nuclei
• Follow-up observations at 16 and 33 GHz of extragalactic sources from WMAP 3-year data: II - Flux-density variability
• The transition from quasar radio-loud to radio-quiet state in the framework of the black hole scalability hypothesis
• Quasi-simultaneous observations of radio and X-ray variability in three radio-quiet Seyfert galaxies
• Optical variability of radio-intermediate quasars
• Radio and X-ray emission from disc winds in radio-quiet quasars
• Tracing the Evolution of Ultraluminous Infrared Galaxies into Radio Galaxies with Low Frequency Radio Observations
• Intranight Optical Variability of Radio-Quiet Weak Emission Line Quasars-IV
• A census of compact sources at 162MHz: first data release from the MWA Phase II IPS Survey
• Lack of Correlations between Cold Molecular Gas and AGN Properties in Type 1 AGNs at $z\lesssim 0.5$
• Kpc-scale Radio Structure in $z\sim 0.25$ Radio-Quiet QSOs
• Mildly Relativistic Motion in the Radio Quiet Quasar PG 1351+640
• Discovery of a radio transient in M81
• The ATESP 5 GHz radio survey. III. 4.8, 8.6 and 19 GHz follow-up observations of radio galaxies
• Optical Microvariability in Quasars: Spectral Variability
• Astrophysics in 2005
• Multi-epoch intra-night optical monitoring of 8 radio-quiet BL Lac candidates
• High-$z$ radio Quasars in RACS I: Selection, identification, and multi-wavelength properties
• RadioSED I: Bayesian inference of radio SEDs from inhomogeneous surveys
• Discovery of A Variable Broad Absorption Line in the BL Lac object PKS 0138-097
• X-ray and Multiwavelength Insights into the Inner Structure of High-Luminosity Disc-Like Emitters
• Compact and variable radio emission from an active galaxy with supersoft X-ray emission
• PKS 1622-253: A Weakly Accreting, Powerful Gamma Ray Source
• Photometric Selection of type 1 Quasars in the XMM-LSS Field with Machine Learning and the Disk-Corona Connection
• Searching for Radio Transients with Inverted Spectra in Epoch 1 of VLASS and VCSS, and Identification of a Sample of Candidate Relativistic Nuclear Transients
• Parsec-Scale Localization of the Quasar SDSS J1536+0441A, a Candidate Binary Black Hole System
• A Giant Metrewave Radio Telescope Survey of Radio-loud Broad Absorption Line Quasars
• A Single Radio Source in the High-redshift Dual AGN LBQS 0302-0019
• Relighting the fire in Hickson Compact Group (HCG) 15: magnetised fossil plasma revealed by the SKA Pathfinders & Precursors
• LOFAR 58 MHz Legacy Survey of the 3CRR Catalog
• Radio-Quiet AGN and the Transient Radio Sky
• A radio, optical, UV and X-ray view of the enigmatic changing look Active Galactic Nucleus 1ES~1927+654 from its pre- to post-flare states
• A Database of Phase Calibration Sources and their Radio Spectra for the Giant Metrewave Radio Telescope
• Using strong lensing to understand the microJy radio emission in two radio quiet quasars at redshift 1.7