J/ApJ/923/31ivo://CDS.VizieR/J/ApJ/923/31doi:10.26093/cds/vizier.19230031CDSSarbadhicary S.K.Tremou E.Stewart A.J.Chomiuk L.Peters C.,Hales C.Strader J.Momjian E.Fender R.Wilcots E.M.2024-11-06T20:23:35Z2023-05-30T15:12:19ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frradio-continuum-emissionactive-galactic-nucleisurveysredshiftedx-ray-sourcesAlthough it is well established that some extragalactic radio sources are time-variable, the properties of this radio variability, and its connection with host galaxy properties, remain to be explored-particularly for faint sources. Here we present an analysis of radio variable sources from the CHILES Variable and Explosive Radio Dynamic Evolution Survey (CHILES VERDES)-a partner project of the 1.4GHz COSMOS HI Large Extragalactic Survey. CHILES VERDES provides an unprecedented combination of survey depth, duration, and cadence, with 960hr of 1-2GHz continuum VLA data obtained over 209 epochs between 2013 and 2019 in a 0.44deg^2^ section of the well-studied extragalactic deep field, COSMOS. We identified 18 moderate-variability sources (showing 10%-30% flux density variation) and 40 lower-variability sources (2%-10% flux density variation). They are mainly active galactic nuclei (AGNs) with radio luminosities in the range of 10^22^-10^27^W/Hz, based on cross-matching with COSMOS multiwavelength catalogs. The moderate-variability sources span redshifts z=0.22-1.56, have mostly flat radio spectra ({alpha}{>}-0.5), and vary on timescales ranging from days to years. The lower-variability sources have similar properties, but generally have higher radio luminosities than the moderate-variability sources, extending to z=2.8, and have steeper radio spectra ({alpha}{<}-0.5). No star-forming galaxy showed statistically significant variability in our analysis. The observed variability likely originates from scintillation on short (~week) timescales, and Doppler-boosted intrinsic AGN variability on long (month-year) timescales.2021ApJ...923...31Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/923/31CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/284 : COSMOS Multi-Wavelength Photometry Catalog (Capak+, 2007)VIII/65 : 1.4GHz NRAO VLA Sky Survey (NVSS) (Condon+ 1998)VIII/87 : The Allen Telescope Array 20cm Survey (ATATS). I. (Croft+ 2010)VIII/103 : Herschel Multi-tiered Extragalactic Survey (Oliver+, 2012)VIII/95 : Herschel Multi-tiered Extragalactic Survey (Oliver+, 2012)J/AJ/127/2565 : Faint FIRST variable radio sources (De Vries+, 2004)J/ApJS/155/271 : CDF-South: Optical spectroscopy (Szokoly+, 2004)J/MNRAS/385/2225 : AzTEC millimetre survey of COSMOS field (Scott+, 2008)J/ApJ/690/20 : Models of AGN & black hole populations (Shankar+, 2009)J/ApJ/699/L43 : FIRST-NVSS-SDSS AGN sample catalog (Smolcic+, 2009)J/ApJS/188/384 : The VLA-COSMOS survey. IV. (Schinnerer+, 2010)J/MNRAS/415/3831 : AzTEC/ASTE source catalogue (Aretxaga+, 2011)J/ApJ/739/76 : Pi GHz Sky Survey (PiGSS). II. (Bower+, 2011)J/ApJ/740/65 : VLA search for 5GHz radio transients (Ofek+, 2011)J/ApJ/742/49 : Var. & transient radio sources in FIRST (Thyagarajan+, 2011)J/MNRAS/436/1919 : SCUBA observations of COSMOS galaxies (Casey+, 2013)J/ApJ/762/93 : PiGSS. III. ELAIS-N1, Coma & Lockman fields (Croft+, 2013)J/ApJ/769/125 : 1.4GHz radio var. in FIRST & SDSS Stripe 82 (Hodge+, 2013)J/AJ/147/143 : MOJAVE. XI. Spectral distributions (Hovatta+, 2014)J/ApJ/819/62 : The COSMOS-Legacy Survey (CLS) catalog (Civano+, 2016)J/ApJS/224/24 : The COSMOS2015 catalog (Laigle+, 2016)J/ApJ/817/34 : C-COSMOS Legacy multiwavelength cat. (Marchesi+, 2016)J/ApJ/818/105 : CNSS pilot survey (Mooley+, 2016)J/A+A/607/A132 : VLBA observations of the COSMOS field (Herrera Ruiz+, 2017)J/ApJS/230/7 : Spectral flux densities from 50MHz to 50GHz (Perley+, 2017)J/A+A/602/A2 : VLA-COSMOS 3 GHz Large Project. II. (Smolcic+, 2017)J/A+A/602/A1 : VLA-COSMOS 3 GHz Large Project (Smolcic+, 2017)J/MNRAS/474/4396 : MASIV Survey. IV. Radio AGNs variability (Koay+, 2018)J/ApJ/874/13 : 24yr of radio observations of V404 Cygni (Plotkin+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/923/31https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/923/31http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/923/31https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/923/31https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/923/31http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/923/31GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/923/31/var (Multi-band and multi-wavelength properties of our CHILES VERDES 18 moderate-variability (Table 2) and 40 low-variability (Table 3) sources)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/923/31/var?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/923/31/var?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/923/31/var?GETtext/xml+votable180.050000true150.027692.373920.0055555555555555565/6814 6/https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/923/31?format=asciiX-rayRadiodefaultJ/ApJ/923/31/varMulti-band and multi-wavelength properties of our CHILES VERDES 18 moderate-variability (Table 2) and 40 low-variability (Table 3) sourcesl_logLxLimit flag on logLxmeta.code.errorcharlogLx[41/44.5]? Log 0.5-8keV X-ray luminosity from Marchesi+ 2016, J/AJ/817/34 ; in units of erg/slog(1e-07W)phys.luminosity;em.X-rayfloatnullablealpha[-1.9/1]? The 1-4GHz spectral indexspect.index;em.radio.1500-3000MHzfloatnullablee_alpha[0.07/0.6]? Uncertainty in alphastat.error;pos.eq.rafloatnullablezbest[0.12/2.7]? Best available redshift measurement from Marchesi+ 2016, J/AJ/817/34src.redshift;pos.heliocentricfloatnullableClassClassification (2)meta.code.classcharS17Display data from Smolcic+ 2017, J/A+A/602/A1 within 1"meta.ref.urlintnullableNpNumber of flux measurements for this sourcemeta.numberintnullableLCLight curve interactive plotsmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVm=moderate or l=low variabilitymeta.codecharIDCHILES VERDES identifiermeta.id;meta.maincharprimaryTRAPInternal ID used by TraP algorithm for sourcemeta.idcharRAJ2000[149.9/150.7] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[2/2.7] Declination (J2000)degpos.eq.dec;meta.mainFlux[0.09/10.4] Median integrated flux densitymJyphot.flux.density;em.radio.750-1500MHzfloatVar[0.01/0.3] Coefficient of variabilitymeta.code;src.varfloateta[1/804] Reduced chi-squared statisticstat.fit.chi2floatSimbadSimbad column added by the CDSmeta.ref.urlcharlogL1.4[22.17/26.4]? Log 1.4GHz luminosity (1)log(W.Hz**-1)phys.luminosity;em.radio.750-1500MHzfloatnullableJ/ApJ/923/31/lcsLight curves for "moderate-variability" (Fig 8) and low-variability (Fig 9) sourcesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintVm=moderate or l=low variabilitymeta.codecharFlux[6.5e-6/0.013] Integrated flux densityJyphot.flux.density;em.radio.750-1500MHzdoublee_Flux[1.4e-5/0.01] Uncertainty in FluxJystat.error;phot.fluxdoubleJDJulian Datedtime.epochdoubleIDCHILES VERDES identifiermeta.id;meta.mainchar