J/A+A/625/A114ivo://CDS.VizieR/J/A+A/625/A114doi:10.26093/cds/vizier.36250114CDSJimenez-Andrade E.F.Magnelli B.Karim A.Zamorani G.Bondi M.,Schinnerer E.Sargent M.Romano-Diaz E.Novak M.Lang P.Bertoldi F.,Vardoulaki E.Toft S.Smolcic V.Harrington K.Leslie S.Delhaize J.,Liu D.Karoumpis C.Kartaltepe J.Koekemoer A.M.2019-07-24T11:30:03Z2019-05-23T14:53:22ZCDS support team

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

cds-question@unistra.frradio-galaxiesgalaxiesphotometryTo better constrain the physical mechanisms driving star formation, we present the first systematic study of the radio continuum size evolution of star-forming galaxies (SFGs) over the redshift range 0.35<z<2.25. We use the VLA COSMOS 3GHz map (noise rms=2.3Jy/beam, {theta}_beam_=0.75arcsec) to construct a mass-complete sample of 3184 radio-selected SFGs that reside on and above the main-sequence (MS) of SFGs. We constrain the overall extent of star formation activity in galaxies by applying a 2D-Gaussian model to their radio continuum emission. Extensive Monte Carlo simulations are used to validate the robustness of our measurements and characterize the selection function. We find no clear dependence between the radio size and stellar mass, M*, of SFGs with 10.5<log(M*/M_{sun}_)<11.5. Our analysis suggests that MS galaxies are preferentially extended, while SFGs above the MS are always compact. The median effective radius of SFGs on (above) the MS of Reff=1.5+/-0.2(1.0+/-0.2)kpc remains nearly constant with cosmic time; a parametrization of the form Reff{prop.to}(1+z)^alpha^ yields a shallow slope of only alpha=-0.26+/-0.08(0.12+/-0.14) for SFGs on (above) the MS. The size of the stellar component of galaxies is larger than that inferred from radio continuum emission by a factor ~2(1.3) at z=0.5(2), indicating star formation is enhanced at small radii. The galactic-averaged star formation rate surface density ({SIGMA}_SFR_) scales with the distance to the MS, except for a fraction of MS galaxies (~10%) that harbor starburst-like {SIGMA}_SFR_. These "hidden" starbursts might have experienced a compaction phase due to disk instability and/or merger-driven burst of star formation, which may or may not significantly offset a galaxy from the MS. We thus propose to use {SIGMA}_SFR_ and distance to the MS in conjunction to better identify the galaxy population undergoing a starbursting phase.2019A&A...625A.114Jhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/625/A114CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/224/24 : The COSMOS2015 catalog (Laigle+, 2016)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/625/A114https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/625/A114http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/625/A114https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/625/A114https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/625/A114http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/625/A114GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/625/A114/catalog (Flux density and size measurements at 3GHz of 3814 radio-selected star-forming galaxies at 0.35<z<2.25)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/625/A114/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/625/A114/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/625/A114/catalog?GETtext/xml+votable180.050000true149.411552.336060.0055555555555555565/6814 6/27245 27247 27344https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/625/A114?format=asciiRadiodefaultJ/A+A/625/A114/catalogFlux density and size measurements at 3GHz of 3814 radio-selected star-forming galaxies at 0.35<z<2.25SNRsignal-to-noise ratiostat.snrdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.mainzPhotometric redshift from the COSMOS2015 catalog; Laigle et al. (2016, Cat. J/ApJS/224/24)src.redshiftfloatlogMassStellar mass from the COSMOS2015 catalog, median of the PDFlog(solMass)phys.massdoubleE_logMassUpper limit, 68% confidence level, for the stellar masslog(solMass)stat.error;stat.maxdoublee_logMassLower limit, 68% confidence level, for the stellar masslog(solMass)stat.error;phys.massdoubleDCFWHMDeconvolved FWHM from PyBDSF, prior correctionarcsecphys.angSizedoublee_DCFWHM68% confidence level for DCFWHM, prior correctionarcsecstat.errordoubleStot3Integrated flux density at 3GHz from PyBDSF, prior correctionJyphot.flux.density;em.radio.1500-3000MHzdoublee_Stot368% confidence level for Stot3, prior correctionJystat.errordoubleSFRTotal SFR (STOT3)=SFR_ir/radio + SFR_UVsolMass/yrphys.SFRdoublee_SFR68% confidence level for SFRsolMass/yrstat.error;phys.SFRdoubleReffEffective radius derived from DCFWHM using the relation: Reff=DCFWHM/2.430; following Murphy et al. (2017ApJ...839...35M)kpcphys.size.radiusdoublee_Reff68% confidence level for Reffkpcstat.errordoubleDCFWHMcDeconvolved FWHM from PyBDSF, after correctionarcsecphys.angSizedoublee_DCFWHMc68% confidence level for DCFWHM, after correctionarcsecstat.errordoubleStot3cIntegrated flux density at 3GHz from PyBDSF, after correctionJyphot.flux.density;em.radio.1500-3000MHzdoublee_Stot3c68% confidence level for Stot3, after correctionJystat.errordoubleSFRcTotal SFR (STOT3c)=SFR_ir/radio + SFR_UVsolMass/yrphys.SFRdoublee_SFRc68% confidence level for SFRcsolMass/yrstat.errordoubleReffcEffective radius derived from DCFWHMc using the relation: Reff=DCFWHM/2.430; following Murphy et al. (2017ApJ...839...35M)kpcphys.size.radiusdoublee_Reffc68% confidence level for REFFckpcstat.errordoubleFlag[0/1] Flag resolved (1)meta.code.errorchar