J/ApJ/731/28ivo://CDS.VizieR/J/ApJ/731/28doi:10.26093/cds/vizier.17310028CDSAlberts S.Calzetti D.Dong H.Johnson L.C.Dale D.A.Bianchi L.,Chandar R.Kennicutt R.C.Meurer G.R.Regan M.Thilker D.2017-06-22T14:28:39Z2012-11-20T14:29:06ZCDS support team

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

cds-question@unistra.frgalaxiesphotometryultraviolet-astronomyinfrared-photometrystellar-associationsWe investigate recent star formation in the extended ultraviolet (XUV) disks of five nearby galaxies (NGC 0628, NGC 2090, NGC 2841, NGC 3621, and NGC 5055) using a long wavelength baseline comprised of ultraviolet and mid-infrared imaging from the Galaxy Evolution Explorer and the Spitzer Infrared Array Camera. We identify 229 unresolved stellar complexes across targeted portions of their XUV disks and utilize spectral energy distribution fitting to measure their stellar ages and masses through comparison with Starburst99 population synthesis models of instantaneous burst populations. We find that the median age of outer-disk associations in our sample is ~100Myr with a large dispersion that spans the entire range of our models (1Myr to 1Gyr). This relatively evolved state for most associations addresses the observed dearth of H{alpha} emission in some outer disks, as H{alpha} can only be observed in star-forming regions younger than ~10Myr. The large age dispersion is robust against variations in extinction (in the range E(B-V)=0-0.3mag) and variations in the upper end of the stellar initial mass function (IMF). In particular, we demonstrate that the age dispersion is insensitive to steepening of the IMF, up to extreme slopes.2011ApJ...731...28Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/731/28CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/ApJS/192/6 : A GALEX UV imaging survey of nearby galaxies (Lee+, 2011)J/AJ/140/1194 : FUV/HI relations in nearby galaxies (Bigiel+, 2010)J/ApJ/714/1256 : Far-IR star formation rate indicators (Calzetti+, 2010)J/ApJ/706/599 : H{alpha} and UV SFR in the local volume (Lee+, 2009)J/ApJ/706/553 : Fluxes in nearby star-forming galaxies (Boquien+, 2009)J/ApJ/703/1672 : Far-IR and H{alpha} fluxes in galaxies (Kennicutt+, 2009)J/ApJ/703/517 : The Spitzer Local Volume Legacy: IR photometry (Dale+, 2009)J/other/RMxAA/44.161 : HII regions in NGC 5055 (Rozas+, 2008)J/ApJS/173/538 : XUV-Disk galaxies in the Local Universe (Thilker+, 2007)J/ApJS/173/185 : GALEX UV atlas of nearby galaxies (Gil de Paz+, 2007)J/AJ/133/791 : Spitzer photometry of galaxies (Smith+, 2007)J/ApJ/656/770 : Mid-IR spectrum of star-forming galaxies (Smith+, 2007)J/ApJ/586/794 : Multiwavelength luminosities of galaxies (Bell, 2003)J/A+AS/114/527 : UV properties of normal galaxies. III. (Rifatto+, 1995)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/731/28https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/731/28http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/731/28https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/731/28https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/731/28http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/731/28GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/731/28/sources (Star forming associations: fluxes, derived ages and masses)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/731/28/sources?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/731/28/sources?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/731/28/sources?GETtext/xml+votable180.050000true24.252291715.855250.0055555555555555566/7240 7241 10841 18398 20526 38390https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/731/28?format=asciiUVOpticalInfrareddefaultJ/ApJ/731/28/sourcesStar forming associations: fluxes, derived ages and massesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNGCGalaxy NC identificationmeta.id.parentintf_Seq[nd] Best fit with (n)o dust or with (d)ustmeta.codecharSeqAssociation identification numbermeta.id;meta.mainintn_Seq[ab] Note on fitting (2)meta.notecharAge0Age with E(B-V)=0Myrtime.ageintl_E_Age0[>] Limit flag on E_Age0meta.code.errorcharE_Age0Positive error on Age0Myrstat.error;stat.maxinte_Age0Negative error on Age0Myrstat.errorintAgeAge with E(B-V)=0.3Myrtime.ageintl_E_Age[>] Limit flag on E_Agemeta.code.errorcharE_AgePositive error on AgeMyrstat.error;stat.maxinte_AgeNegative error on AgeMyrstat.error;time.ageintlogM0Log of Mass with E(B-V)=0log(solMass)phys.massfloatE_logM0Positive error on logMass0log(solMass)stat.error;stat.maxfloate_logM0Negative error on logMass0log(solMass)stat.errorfloatlogMLog of Mass with E(B-V)=0.3log(solMass)phys.massfloatE_logMPositive error on logMasslog(solMass)stat.error;stat.maxfloate_logMNegative error on logMasslog(solMass)stat.errorfloatRAJ2000Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000Degree of Declination (J2000)pos.eq.dec;meta.mainFUVGALEX FUV band flux (1)zW.m**-2.nm**-1phot.flux;em.UVdoublee_FUVThe 1{sigma} uncertainty in FUV (1)zW.m**-2.nm**-1phot.flux;em.UVfloatNUVGALEX NUV band flux (1)zW.m**-2.nm**-1phot.flux;em.UVfloate_NUVThe 1{sigma} uncertainty in NUV (1)zW.m**-2.nm**-1phot.flux;em.UVfloatF3.6Spitzer/IRAC 3.6 micron flux (1)zW.m**-2.nm**-1phot.mag;em.IR.3-4umfloate_F3.6The 1{sigma} uncertainty in F3.6 (1)zW.m**-2.nm**-1stat.errorfloatF4.5Spitzer/IRAC 4.5 micron flux (1)zW.m**-2.nm**-1phot.mag;em.IR.4-8umfloate_F4.5The 1{sigma} uncertainty in F4.5 (1)zW.m**-2.nm**-1stat.errorfloatF5.8Spitzer/IRAC 5.8 micron flux (1)zW.m**-2.nm**-1phot.flux.density;em.IR.4-8umdoublee_F5.8The 1{sigma} uncertainty in F5.8 (1)zW.m**-2.nm**-1stat.errorfloatF8.0Spitzer/IRAC 8.0 micron flux (1)zW.m**-2.nm**-1phot.flux.density;em.IR.8-15umfloate_F8.0The 1{sigma} uncertainty in F8.0 (1)zW.m**-2.nm**-1stat.errorfloat