Hoopes, C., et al. 2007, ApJS, 173, 441

16 Pages·2008·5.01 MB·English

TheAstrophysicalJournalSupplementSeries,173:441Y456,2007December
#2007.TheAmericanAstronomicalSociety.Allrightsreserved.PrintedinU.S.A.
THE DIVERSE PROPERTIES OF THE MOST ULTRAVIOLET-LUMINOUS GALAXIES
DISCOVERED BY GALEX
Charles G. Hoopes,1 Timothy M. Heckman,1 Samir Salim,2 Mark Seibert,3 Christy A. Tremonti,4
David Schiminovich,5 R. Michael Rich,2 D. Christopher Martin,3 Stephane Charlot,6,7
Guinevere Kauffmann,6 Karl Forster,3 Peter G. Friedman,3 Patrick Morrissey,3
Susan G. Neff,8 Todd Small,3 Ted K. Wyder,3 Luciana Bianchi,1 Jose´ Donas,9
Young-Wook Lee,10 Barry F. Madore,11 Bruno Milliard,9
Alex S. Szalay,1 Barry Y. Welsh,12 and Sukyoung K. Yi10
Received2006June6;accepted2006September7
ABSTRACT
Wereportonthepropertiesofasampleofultraviolet-luminousgalaxies(UVLGs)selectedbymatchingtheGalaxy
EvolutionExplorer(GALEX)All-SkyImagingandMediumImagingSurveyswiththeSloanDigitalSkySurveythird
datarelease.Theoverlapbetweenthesetwosurveysisroughly450deg2.Of25,362galaxies(withSDSSspectroscopy)
intherange0:0<z<0:3detectedbyGALEX,thereare215galaxieswithL>2;1010L at15308(observedwave-
length). The properties of this population are well correlated with ultraviolet surface b!rightness. We find that the
galaxieswithlowUVsurfacebrightnessareprimarilylargespiralsystemswithamixtureofoldandyoungstellarpop-
ulations,whilethehighsurfacebrightnessgalaxiesconsistprimarilyofcompactstarburstsystems,withanapproximate
boundaryatasurfacebrightnessofI 108L kpc 2.Thelargegalaxiesappeartobethehigh-luminositytailofthe
1530 #
galaxystarformationfunctionandowe¼theirlar!geluminositytotheirlargesurfacearea.Intermsof thebehaviorof
surfacebrightnesswithluminosity,sizewithluminosity,themass-metallicityrelation,andotherparameters,thecom-
pactUVLGsclearlydepartfromthetrendsestablishedbythefullsampleof galaxies.Thesubsetof compactUVLGs
withthehighestsurfacebrightness(I >109 L kpc 2;‘‘supercompactUVLGs’’)havecharacteristicsthatarere-
1530 #
markablysimilartoLymanbreakgalaxiesathigher!redshift.Theyaremuchmoreluminous(andthushavemuchhigher
starformationrates)thantypicallocalultraviolet-brightstarburstgalaxiesandbluecompactdwarfgalaxies.Theyhave
metallicitiesthataresystematicallylowerthannormalgalaxiesof thesamestellarmass,indicatingthattheyareless
chemicallyevolved.Inalltheserespects,theyarethebestlocalanalogsforLymanbreakgalaxies.
Subject headinggs: galaxies: evolution — galaxies: starburst — ultraviolet: galaxies
1. INTRODUCTION This picture still contains some uncertainty resulting from
severalfactors.Thestarformationratedensityatlowredshift
Overthepastdecadeenormousprogresshasbeenmadetoward
(z 0Y1)hasbeendeterminedthroughdifferenttechniques(e.g.,
mapping the cosmological history of star formation in the uni- ¼
H!luminosity)thanthoseusedforhigherredshiftgalaxies(e.g.,
verse(e.g.,Madauetal.1996;Giavaliscoetal.2004).Thishas
rest-frame ultraviolet luminosity). These techniques are affected
mainlybeenaccomplishedusinglargesamplesof high-redshift
differentlybyextinctionandradiativetransfereffects,andthey
galaxiesselectedbytheirrest-frameultraviolet(UV)colors(e.g.,
fundamentallyprobestarformationoverdifferenttimescales.
Steideletal.1996,2003;Dickinsonetal.2004).Thesesurveys
Onewayaroundthisproblemistoobtainrest-frameultravi-
indicatethattheglobalstarformationrateoftheuniversehasbeen
olet (UV) measurements for a large sample of galaxies at low
indeclinesincez 1Y2andwasgenerallyconstantathigherred-
$ redshift,enablingthemeasurementof starformationratesusing
shiftouttoatleastz 6(Giavaliscoetal.2004).
¼ thesametechniquesthatareusedathigherredshift.Thisrequires
aUVtelescopeinspacewithalargefieldofview,somethingthat
has not been available until the Galaxy Evolution Explorer
1 DepartmentofPhysicsandAstronomy,JohnsHopkinsUniversity,Home-
(GALEX) mission (Martin et al. 2005). GALEX is obtaining
woodCampus,Baltimore,MD21218.
2 Department of Physics and Astronomy, University of California, Los UVfluxesformorethan 107galaxiesintheredshiftrangeof
$
Angeles,CA90095. 0<z<2. Initial results on the UV luminosity density show
3 CaliforniaInstituteofTechnology,MC405-47,Pasadena,CA91125. strongevolutionfromz 2to0,withthestrongestevolutionoc-
4 StewardObservatory,Universityof Arizona,933NorthCherryAvenue, ¼
curringinthemostUV-luminousgalaxies(Schiminovichetal.
Tucson,AZ85721.
5 DepartmentofAstronomy,ColumbiaUniversity,NewYork,NY10027. 2005;Arnoutsetal.2005).ThefractionofgalaxieswithL1530 >
6 Max-Planck-Institut fur Astrophysik, D-85748 Garching bei Munchen, 0:2L ;z 3 fellbyafactorof 30fromz 1to0(usingL ;z 3
Germany. 6;1%01¼0 L ;Steideletal.1999). ¼ % ¼ ¼
7 Institutd’AstrophysiquedeParis,UMR7095,F-75014Paris,France. These U!V-luminous galaxies at high redshift are more com-
8 LaboratoryforAstronomyandSolarPhysics,NASAGoddardSpaceFlight
monlycalledLymanbreakgalaxies(LBGs;Steideletal.1999).
Center,Greenbelt,MD20771.
9 Laboratoired’AstrophysiquedeMarseille,BP8,13376MarseilleCedex12, Thesehigh-redshiftgalaxiesaresonamedbecausetheyareiden-
France. tifiedbytheeffectsoftheLymanbreakontheirbroadbandcolors
10 CenterforSpaceAstrophysics,YonseiUniversity,Seoul120-749,Korea. (Steidel&Hamilton1993).LBGsareUV-brightgalaxiesunder-
11 Observatoriesof theCarnegieInstitutionof Washington,Pasadena,CA
goingintensestarformationwithlowtomoderatestellarmasses
91101.
12 Space Sciences Laboratory, University of California at Berkeley, 601 (logM 9:5Y11:0M ) andare candidates for theprecursors
CampbellHall,Berkeley,CA94720. of pres%e¼nt-day elliptica!l galaxies (see, e.g., Giavalisco 2002).
441
442 HOOPES ETAL. Vol. 173
LBGsarecommonatz>2,andtheyareclearlyimportantasthe thedataandautomaticallydetects,measures,andproducescata-
sitesof asignificantfractionof allthestarformationintheuni- logsof FUVandNUVfluxesforsourcesintheGALEXimages.
verse.SincestrongevolutionhasmadeobjectslikeLBGsextremely
2.2.Optical Data
rareinthelocaluniverse,allof theinformationonthisimportant
galaxypopulationhascomefromverydistantsamples,whichare The GALEX catalogs were then matched to the SDSS third
inherentlydifficulttostudy.Thus,therehasbeenlittledetailedin- datarelease(DR3;Abazajianetal.2005)spectroscopicsample.
formationavailableontheprocessesdrivingtheevolutionof star Theareaof theoverlapregionbetweenGR1andDR3isabout
formationinthepopulationof LBGs. 450deg2(Bianchietal.2007).TheSDSScatalogprovides(among
UsinglocalUV-brightstarburstsaslocalanalogstoLBGshas manyotheravailableparameters)ugrizmagnitudes,spectroscopic
contributed significantly toward understanding these objects redshifts,concentrationparameters,observedhalf-lightradii,and
(Heckmanetal.1998;Meureretal.1999).However,localstar- model-fitexponentialscalelengths.Tobeincludedinourfinal
burstsdifferfromLBGsinimportantways.Localstarburstsare matchedcatalog,werequiredthateachsourcehaveaspectroscopic
usually dwarf galaxies or small (subkiloparsec) regions in the redshift in the range 0<z<0:3 and that the SDSS source be
nucleioflargergalaxies,whileLBGshavetypicalsizesofafew spectroscopicallyclassifiedasagalaxy,excludingobjectsclas-
kiloparsecs(Fergusonetal.2004).Luminouslocalstarburstsare sifiedbytheSDSSpipelineasQSOsortypeI(broadline)active
usuallyverydustysystemsinwhichonlyasmallfractionof the galacticnuclei(AGNs).TheresultingGR1/DR3samplecontains
UV light escapes, while LBGs with similar bolometric lumi- 25,362galaxies.Ofthese,18,463have3"FUVdetections.The
nosities(starformationrates)typicallycontainmodestamounts remaininggalaxiesweredetectedintheNUVimagesonly.
ofdust(e.g.,Reddyetal.2006;Erbetal.2006a).Giventhesedif- WiththedistancesestimatedfromtheSDSSredshift,theFUV
ferences,itisnotclearthattheconditionsinlocalstarburstsorthe (andNUV)luminosityforeachgalaxyisknown.FollowingPaperI,
triggersof starformationareidenticaltothoseinLBGs,andso galaxieswithL >2;1010 L qualifyasUV-luminousgal-
1530
thereisaneedforbetterLBGanalogsinthelocaluniverse. axies13,whereL isthelumino!sityattheobservedwavelength
1530
Since LBGs are found in part by their large UV luminosity, of15308.Thisluminosityis 5L forz 0(Wyderetal.2005)
LBGanalogsinthelocaluniverseshouldalsobeUV-luminous. and 0.3L forLBGsatz $3(S%teidel¼etal.1999).Thereare
Thelarge-areaUVskysurveysbeingcarriedoutbyGALEXpro- 235g$alaxie%sintheGR1/DR¼3samplethatmeetthiscriterion.We
vide anideal data set for finding rare UV-luminousgalaxiesin then inspected the SDSS spectra of these galaxies to eliminate
thelocaluniverse.Heckmanetal.(2005,hereafterPaperI)de- broad-line (type I) AGNs that were missed by the SDSS pipe-
scribedthepropertiesofthemostUV-luminousgalaxies(UVLGs) line,aswellasobjectswithBLLacYtypespectra(UV-brightbut
inthelocaluniversebasedoncross-matchingtheinitialGALEX withweakornonexistentemissionlines).TypeIIAGNsinthe
surveys with the Sloan Digital Sky Survey (SDSS) first data samplearediscussedin 4.4.The215galaxiesthatremainare
release(DR1;Abazajianetal.2003).TheUVLGswerecomposed hereafterreferredtoasuxltraviolet-luminousgalaxies(UVLGs).
of two basic types of galaxies: large UVLGs, which are charac- Thesegalaxiesspantheredshiftrangefromz 0:053to0.3.
terizedbylowerUVsurfacebrightnessandhighmass,andcompact Alargenumberof galaxyparametersderive¼dfromtheSDSS
UVLGs,whichhavehigherUVsurfacebrightnessandlowermass. spectraareavailableinthevalue-addedcatalogsproducedbythe
ManyofthecompactUVLGshavepropertiesverysimilartothose SDSScollaboration.ThesecatalogsareavailableattheSDSSWeb
of LBGs. site14attheMaxPlanckInstitute.Fromthesecatalogsweusethe
Althoughthissamplewasveryilluminating,severalquestions emission-linefluxes,widths,andderivedmetallicities.Formore
remain.TheextentofthesimilaritybetweenthecompactUVLGs informationonthederivationoftheseparameters,seeKauffmann
andLBGsisacrucialquestion.Moregenerally,itisnotknown et al. (2003a, 2003b, 2003c), Brinchmann et al. (2004), and
whetherthesegalaxiesaretrulyadistinctpopulationofobjectsin Tremontietal.(2004).Thesecatalogsdonotincludemetallicities
anearlierphaseofevolution,i.e.,remnantsoftheepochofgalaxy forgalaxieswithanAGNcontribution,sincethiscanstronglyaf-
formation,orwhethertheyaresimplythehighendoftheUVlu- fectthelinestrengths,soonlyasubsetof oursamplehavemet-
minosity function. Many of these questions could be better ad- allicitydeterminations.Inaddition,somegalaxieshavepoorline
dressedifthereweremoresuchgalaxiesavailableforstudy,sowe fluxmeasurementsbecausetheemissionlinesinthefiberaperture
presentananalysisof alargersampleof UVLGs,basedonmore areweakornonexistent,e.g.,ingalaxieswithnostarformation
recentGALEXandSDSSdata. inthecentralregionofthegalaxy.Thus,linefluxmeasurements
existforonlyasubsetof oursample.
2. DATA
2.3. Spectral Energy Distribution Modeling
2.1.Ultraviolet Data
Togainfurtherinformationaboutthepropertiesofthegalaxies
Sinceitslaunchin2003April,GALEXhasbeenconducting inoursample,wecomparedtheobservedopticalandUVproper-
severalsurveysof theUVsky.Inthispaperwemakeuseof the tiesof oursampletoalibraryof modelspectralenergydistribu-
GALEX All-Sky Imaging Survey (AIS) and Medium-deep Im- tions(SEDs),followingSalimetal.(2005).Thiswasdonebyfirst
aging Survey (MIS). The data were taken from thefirst public constructingthebroadbandopticalandUVSEDsfromtheSDSS
releaseof GALEXdata(GR1)availableattheMultimissionAr- andGALEXmagnitudes.EachobservedSEDwasthencompared
chive atSpaceTelescope(MAST).Details onthe GALEXmis- toanextensivelibraryofSEDsgeneratedbytheBruzual&Charlot
sionandsurveysaregiveninMartinetal.(2005). (2003)populationsynthesiscode.Eachmodelgalaxyisbasedona
TheGALEXdataincludefar-ultraviolet(FUV;keA 15288, starformationhistorycomposedofanexponentiallydecliningstar
¼
!k 2688)andnear-ultraviolet(NUV;keA 22718,!k formationrate(SFR)withsuperimposedburstsofstarformation
¼ ¼ ¼
7328)imageswithacircularfieldofviewwithradius 380.The andincludestheeffectsofattenuationbydust(seeCharlot&Fall
$
spatialresolutionis 500.DetailsoftheGALEXsatelliteanddata 2000). The library contains 105 models at each of five evenly
$
characteristicscanbefoundinMorrisseyetal.(2005).
linTehatethdeatCaawlieforernpiaroIcnesstisteudtetohfroTuegchhnthoeloGgyA.LTEhXepriepdeulicnteiornedpuipcees- 1134 TSeherohutgtph:o//uwtwthwis.mpappae-grawrcehuinseg.Hm0p¼g.d7e0/SkDmSsS#.1,"m¼0:3,and"#¼0:7.
No. 2, 2007 UV-LUMINOUS GALAXIES DISCOVERED BY GALEX 443
Fig. 2.—Normalizedcontourplotoftheu-bandhalf-lightradiusvs.FUV
Fig.1.—NormalizedcontourplotoftheFUVsurfacebrightnessvs.FUVlu-
luminosityfor18,463galaxiesintheGR1/DR3samplethathaveFUVdetections.
minosityfor18,463galaxiesintheGR1/DR3samplewithFUVdetections.The
Theluminositybinsarenormalizedtohavethesamenumberofgalaxiesineach
luminositybinsarenormalizedtohavethesamenumberofgalaxiesineachbin.
bin.CountoursareasinFig.1.TheSDSSu-bandhalf-lightradiusisderivedfrom
Eachpairofcontoursrepresentsafactorof2increaseintheenclosedfractionof
anexponentialmodelfitandincludesaseeingcorrection.Thedashedlinesde-
galaxiesintheluminositybinthathavesurfacebrightnessinagivenrange,with noteFUVsurfacebrightnesslevelsofI 108L kpc 2(upperline)andI
thecentralpairofcontoursenclosing84%ofthegalaxiesintheluminositybin 109L kpc 2(lowerline).Thesolidli1n53e0s¼howsthe!regi#ontypicallypopula1te53d0b¼y
andtheouterpairofcontoursenclosing99.5%ofthegalaxies.FUVluminosity LBGs!.The#datapointsinthisfigurehavebeencorrectedforGalacticforeground
(L1530)isdefinedaskPkat15308(observedwavelength).FUVsurfacebright- extinctionbutnotforinternalextinction.
nessisdefinedasI1530¼L1530/(2#r520;u),wherer50;uistheSDSSu-bandhalf-light
radius(correctedforseeing).Thedatapointsinthisfigurehavebeencorrectedfor
Galactic foreground extinction but not for internal extinction. The dashed line ever,forwell-resolvedgalaxieswefoundthattheseeing-corrected
showstheregiontypicallypopulatedbyLBGs. radius derived from the exponential model fits issystematically
largerthanthedirectlyobservedhalf-lightradius.Wefoundthat
spacedredshiftsfromz 0:05to0.25,andthegridof models thisoccursforgalaxieswithhalf-lightradiilargerthanabout2.2 .
¼ 00
wasconstructedtospanthelikelyrangeofstarformationhistories. We thus use the observed u-band half-light radius as r for
50;u
ThegoodnessoffitforagivenmodeltoanobservedSEDis galaxieslargerthan2.2 ,andtheseeing-correctedscalelength
00
thentranslatedtoaprobabilitythattheparametersforthatmodel asr forgalaxiessmallerthan2.2 .Wecanthencalculatethe
50;u 00
applytothegalaxy.Thus,theparametersofthebest-fittingmodel effectivesurfacebrightnessbydividingone-halftheluminos-
willhavethehighestprobability,andaprobabilitydistributioncan itybytheareaof thegalaxyenclosedbythehalf-lightradius
be constructed for the entire library at the appropriate redshift. (I L /2#r2 ).
From this the median and 95% confidence limits on each pa- 1F53i0gu¼re115s3h0owsa50n;uormalizedcontourplotoftheFUVsurface
rametercanbedetermined.Thiswasdoneforalistofparameters brightnessversusFUVluminosityforthe18,463galaxiesinthe
including stellar mass and star formation rate over a range of GR1/DR3samplethatweredetectedintheFUVimages.Thelu-
timescales.FormoreinformationontheSEDfittingprocess,see minositybinswerenormalizedtohavethesamenumberof gal-
Salimetal.(2005).Inthispaperthestellarmassesandstarfor- axies in each bin, thus clarifying the dependence of surface
mationratesweredeterminedthroughSEDfitting. brightness on luminosity by removing the effects of having a
smallernumberofgalaxiesatthelow-andhigh-luminosityends
3. PROPERTIES OF THE GR1/DR3 GALAXY SAMPLE
of thedistribution.
The GALEX-SDSS matched catalog provides a valuable re- The plot shows a well-defined trend of slightly increasing
sourceforstudyingtheUV-opticalpropertiesofstar-forminggal- surfacebrightnesswithincreasingluminosityovertheentirelumi-
axiesinthelocaluniverse.Inafuturepaperwewillreportonthe nosityrange.However,atthehighluminositiescorrespondingto
analysisof theentiregalaxysample.Hereweconcentrateonthe theUVLGsthereisananomalouspopulationofgalaxiesthatdefy
relationshipbetweenUVLGsandthebroadergalaxypopulation. thegeneraltrendbyhavingamuchhighersurfacebrightnessthan
The galaxy sampleconsidered here should be nearly devoid wouldbeexpectedgiventheirluminosity.Thesegalaxieshave
ofunobscured(typeI)AGNs,sothedominantsourceoftheUV I 108L kpc 2.OnlyamongtheUVLGsaregalaxieswith
lightdetectedbyGALEXismassivestars.TheUVluminosityof th15e30hi&ghestsu!rfaceb#rightnesses(I 109L kpc 2)relatively
1530 #
a galaxy therefore traces the total amount of star formation in common. & !
thatgalaxyoverthepast108yr(Martinetal.2005).Wealsohave Figure 2 shows the dependence of half-light radius on lumi-
measurementsof thesizesof thesegalaxies.Mostof thesegal- nosity.ThesurfacebrightnessparametershowninFigure1depends
axiesareonlymarginallyresolvedintheGALEXimages,sowe onthehalf-lightradius,soFigure2isanalternativerepresentation
usedthehalf-lightradiimeasuredonthehigherresolutionSDSS of Figure1.Overmostof therangeinluminositytheradiusin-
images.TheSDSSubandwaschosenbecauseitistheclosestin creaseswithincreasingluminosity.AboveL >1010L there
1530
wavelengthtotheGALEXbandsandthereforethemostlikelyto isagroupofgalaxiesthatdonotobeythistrendinthesen!sethat
reflectthetruespatialextentof starformation.Inmostcaseswe theyaretoosmallfortheirluminosity.ThedashedlinesinFigure2
usethescalelengthfromtheseeing-correctedexponentialmodel arelinesof constantI ,andthegalaxiesresponsibleforthis
1530
fitcalculatedbytheSDSSpipelineasthehalf-lightradius.How- deviationfromthetrendhaveI >109 L kpc 2.
1530 #
!
444 HOOPES ETAL.
UVLGsrelatetotherestofthesampleintermsofmass(butkeep
in mindthatthecontoursare normalizedbythe numberof gal-
axiesineachmassbin).TheUVLGswithI <108 L kpc 2
1530 #
areamongthemostmassivestar-forminggalaxiesintheGR!1/DR3
sample,withlogM 10:5M .Whilethesearethelowersur-
face brightness com%p&onent of !the UVLG sample, they are still
somewhat offset toward higher surface brightness than the full
sample(theyarenotlowsurfacebrightnessgalaxies).Inthemain,
theirpropertiesappeartobesimilartothoseoflarge,diskgalaxies
(theyaretheextremaof thepopulation).
The UVLGs with I >108 L kpc 2 are generally lower
1530 #
masssystems(logM 10:5M ).!Theyclearlystandoutfrom
thefull sample byha%v’ing much!higher surface brightness than
wouldbeexpectedfornormalgalaxiesof similarmass.Thisis
evenmoreobviousforgalaxieswithI >109L kpc 2,which
1530 #
wouldqualifyasLBGsbasedontheirFUVsurfa!cebrightness.
Based on the analysis above, the UVLG population can be
thoughtof astwoverydifferenttypesof galaxies.Thehighsur-
face brightness systems (‘‘compact UVLGs’’) have high star
formation rates per unit area and would be called starburst gal-
Fig. 3.—NormalizedcontourplotoftheFUVsurfacebrightnessvs.stellar axies,whilethelowsurfacebrightnesssystems(‘‘largeUVLGs’’)
massforthe18,463galaxiesintheGR1/DR3samplethathaveFUVdetections. arelargespirals,withhighratesof totalstarformationbutlow
Thestellarmassbinsarenormalizedtohavethesamenumberofgalaxiesineach ratesof starformationperunitarea.Thereisnocleartransition
bin.Eachpairofcontoursrepresentsafactorof2increaseintheenclosedfraction
fromonepopulationtotheother,butasurfacebrightnessvalue
ofgalaxiesinthemassbinthathavesurfacebrightnessinagivenrange,withthe
centralpairofcontoursenclosing84%ofthegalaxiesinthemassbinandtheouter of I1530 108 L kpc#2servesasausefulboundary.Thereare
pairofcontoursenclosing99.5%ofthegalaxies.Theindividualgalaxiesinthe intermed¼iate cas!es that do not fit cleanly into either category.
UVLGsampleareshownaspointsintheplot.Theboundariesofmassandsurface Figure3showsthatthissurfacebrightnessboundarycorresponds
brightnessfortypicalLBGsarealsoshowninthefigure,asistheboundarybetween toastellarmassof roughlyM 1010:5M (similartothemass
largeandcompactUVLGs. scalethatdividesthebimodal%ga¼laxypopul!ationasawhole;e.g.,
Kauffmann et al. 2003b). Using this criterion there are 110
ThesetwofiguresshowthatingeneralgalaxieswithhigherUV largeUVLGsand105compactUVLGsintheGR1/DR3sample.
luminosity are larger and have somewhat higher surface bright- Thesetwo diverse populations were recognized in Paper I, but
nessthantheirlessluminouscounterparts.Athighluminosities, wecannowplacethemfirmlyinthecontextoftheoverallgalaxy
however,somegalaxiesbehavedifferently.Theyhavesmallradii, population.
but this is more than compensated by their increased surface Throughouttherestofthispaperwedistinguishbetweenlarge
brightnesstoputthemamongthemostUV-luminousgalaxiesin and compact UVLGs. Note, however, that while the compact
thesample.ThisisastrongindicationthattheseUVLGsaredis- UVLGshavethepropertiesofintensestarbursts,notallofthem
tinct from the general galaxy population. By contrast, UVLGs have FUV surface brightnesses high enough to be considered
withlowersurfacebrightnessdonotdistinguishthemselvesfrom typicalLBGs, whichgenerally haveI >109 L kpc 2. We
1530 #
thefullsampleofgalaxiesexceptbytheirluminosity.Theyappear considerthecompactUVLGsthatmeetthismores!tringentsur-
tobethelargestandthereforemostluminousnormalgalaxies. facebrightnesscriterionaspossibleLBGanalogs,andwerefer
Figure3showshowtheUVsurfacebrightnesschangeswith tothemas‘‘supercompactUVLGs.’’TheGR1/DR3samplecon-
stellarmass,asdeterminedfromtheSEDmodelfitting(Salimetal. tains35supercompactUVLGs.
2005).Ingeneral,thestellarmassdeterminedinthismanneragrees
to within a factor of 2 with the dynamical mass calculated as 4. PROPERTIES OF ULTRAVIOLET-
Mdyn 3:4"g2asr50;u/G, where "gas is the standard deviation of LUMINOUS GALAXIES
¼
thegasvelocitymeasuredfromtheemissionlines.Thecoefficient
SincetheUVLGsamplewaschosenbasedonanultravioletlu-
3.4wastakenfromErbetal.(2006b)andrepresentsarealistices-
minositycriterion,theyareallexpectedtohavehighstarforma-
timateofthemassdistributionforLBGs.TheUVsurfacebright-
tion rates. As in Paper I, the majority of UVLGs (83%) have
nessisrelativelyconstantoverawiderangeofstellarmassesand
thenslowlyfallsaboveamassof1010.5M .Thisimpliesthatthe concentrationparametersC <2:6,whereCisdefinedasR90/R50,
theratioof theradiuscontaining90%of thePetrosianr-bandlu-
moremassive galaxies have correspondi!nglylarger sizes over
minosity to that containing 50%. These low concentration pa-
which the young stellar population is distributed. The drop in
rametersareindicativeofdisksystems,asexpectedforasample
surfacebrightnessabove1010.5M mayberelatedtotherela-
ofstar-forminggalaxies.Yet,aswasmadeclearintheprevious
tivelyabrupttransitioninthegalaxy!populationatthismassscale
section,UVLGsspanawiderangeofproperties.Inthissection
betweenyoungdisk-dominatedgalaxiesandoldbulge-dominated
weexplorethepropertiesofUVLGs.Thepropertiesofthe215
ones(e.g.,Kauffmannetal.2003b).
UVLGsarelistedinTable1.
ThepointsshowninFigure3arethelocationsof individual
UVLGs.Unlikethegalaxy population asawhole,theUVLGs
4.1. Ultraviolet Surface Brightness
showaclearinversecorrelationbetweensurfacebrightnessand
mass.Wehavealreadypointedoutthatthisfactindicatesthatthe Figure4plotstheFUVsurfacebrightnessof the215UVLGs
moremassiveUVLGsowetheirlargeluminositiestotheirlarge againsttheFUVluminosity.Thegalaxieswerechosentobelu-
mass.ThelessmassiveUVLGshavehighUVsurfacebrightnesses minous, but they span a wide range in surface brightness, and
indicative of intense star formation. Figure 3 shows how the thereisnocorrelationbetweenluminosityandsurfacebrightness.
)
H
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log((13) 8.89...8.899.028.678.748.719.029.06...8.968.89...8.96...9.118.948.23.........8.609.27......9.018.658.72......8.898.789.11...9.14............8.67......8.708.878.98...
þ
2
1
logSFR1Myr)#!(12) 1.030.761.440.601.071.181.711.151.200.951.251.350.450.660.13#0.211.060.410.910.841.391.131.061.921.180.570.920.780.530.690.29#1.440.782.410.911.630.531.230.990.550.20#0.861.440.911.290.01#
(
logM%(M)!(11) 10.0810.7610.6710.569.9810.439.7610.6210.9911.6210.7410.2810.7610.2710.4410.6110.779.1811.2711.2410.7110.4111.1011.0010.0711.0810.0210.1710.9411.109.9310.0910.8611.7010.7811.4811.0711.1211.709.5611.1411.0610.0810.4210.5211.32
A1530(mag)(10) 0.803.251.512.261.421.000.372.962.352.211.731.371.702.272.851.912.180.139.200.63...1.313.411.97...0.001.381.471.9910.440.660.801.831.432.01...3.262.632.230.560.000.000.481.261.192.21
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121011010001000 000000020 1101 01110 00000000
NUV(mag)(9) 160.)090.)340.)870.)550.)860.)870.)860.)270.)990.)920.)350.)570.)830.)190.)...130.)030.)280.)940.)520.)740.)160.)460.)720.)...300.)760.)110.)720.)...290.)940.)690.)550.)020.)...810.)080.)410.)360.)310.)030.)260.)530.)...
0.0.0.8.9.9.7.9.9.9.7.9.9.8.0. 9.1.0.8.9.8.9.0.8. 9.9.9.9. 9.9.9.9.9. 8.0.8.9.9.9.8.9.
222111111111112 122111121 1111 11111 12111111
5855238287974433580154514408203324763473555365
2221220200010100101101031022020221110000000000
FUVmag)(8) 10.)20.)40.)60.)80.)90.)20.)70.)00.)30.)50.)30.)70.)90.)30.)20.)40.)20.)60.)20.)50.)40.)20.)40.)90.)30.)60.)10.)40.)20.)00.)60.)40.)40.)30.)50.)10.)60.)50.)20.)70.)20.)80.)50.)00.)10.)
( 5042010095261080366973561294180900426257595502
0.9.0.9.0.0.8.0.9.0.8.9.9.9.8.8.9.0.0.8.9.9.9.0.9.9.9.0.7.9.8.9.0.9.9.9.8.9.0.8.9.9.9.8.0.9.
2121221212111111122111121112111121111121111121
)
1 mple ogI15302kpc#!(7) 8.557.588.297.858.329.378.727.937.586.858.668.397.777.557.538.637.799.167.247.809.048.717.708.399.898.438.888.328.267.619.088.367.738.757.877.557.537.716.618.537.587.228.669.389.358.04
E a lL
L S (
B G
TA UVL r50u;(kpc)(6) 3.139.625.147.694.131.383.246.5512.5223.682.704.138.9810.409.983.999.261.7213.8113.082.302.869.284.040.804.742.384.1811.2411.281.684.088.695.026.8212.5811.918.5230.633.479.8414.623.211.661.537.58
ogL1530(L)!(5) 10.3410.3410.5110.4210.3510.4510.5410.3610.5710.4010.3210.4210.4710.3810.3310.6310.5210.4310.3210.8310.5610.4210.4310.4010.4910.5810.4310.3611.1610.5110.3310.3810.4110.9510.3410.5510.4810.3710.3810.4110.3610.3510.4710.6210.5210.60
l
edshift(4) 0.2500.1340.2880.1610.2110.2430.1080.2110.2460.2670.0940.1870.1640.1440.1230.1190.1840.2830.2590.2130.2270.1660.1810.2780.1670.1890.2180.2430.1440.2230.0860.2070.2200.2530.1590.1840.1300.1530.2630.1280.1720.1980.1930.1470.2430.191
R
5146854480717054089026485808812982985832959857
7220164559217248639664745087906192630175754564
Decl.(deg)(3) 1.1560.735#1.071#0.842#11.0350.767#0.8450.06710.93611.0250.940#0.877#9.198#9.028#11.12915.04210.88615.56915.3650.05915.4860.86515.72714.4410.363#9.823#0.64616.03515.64513.54614.9100.842#0.1271.0561.15813.43414.77614.6369.129#10.18914.25210.21113.91013.14913.41913.197
# ## # # # #
8213071547977624852327733393541798909047644184
2390358625849443135625604200074567456107545327
R.A.(deg)(2) 0.2011.4661.7732.4022.4532.5412.7862.8603.4383.9974.3674.7818.6038.7198.8489.0699.58810.22610.52310.94711.19711.61111.69412.19113.86414.14714.19614.69214.98415.36015.61216.03316.56316.70516.80917.31420.14121.25821.54125.59826.26926.80126.81527.61827.85827.952
SObjID(1) 629504..................294786..................554916..................192547..................306171..................753479..................302646..................626537..................764940..................961583..................109826..................241048..................476771..................705169..................416108..................057678..................386334..................387411..................518558..................165442..................780648..................169371..................140399..................724283..................539596..................322564..................853386..................256545..................289961..................132105..................810262..................815637..................590315..................497820..................497878..................983886..................808483..................332766..................404773..................496000..................429914..................338983..................821098..................180186..................409001..................376839..................
S 4691464044224062799498218930844065548990194686
D 1953594755330011544744103285801371107766844404
S 78817651518103925151515173067988519393929303372187957242987288159242427231310084319426772177
8008201022882879299091330783999101193387323939
1551255522112111211515225112111555512211222121
1551755577117774744545445714444151144477474444
3113211122332222222121221232222313322222222222
7007700077777777777070770777777707777777777777
7887788877777777777878778777777787777777777777
8888888888888888888888888888888888888888888888
5555555555555555555555555555555555555555555555
)
H
O/
log((13) 9.10.........8.85...9.008.839.008.618.87...8.879.068.98...8.88......9.318.838.858.788.619.02...9.149.039.079.038.828.588.988.539.119.06...8.99...8.689.06...9.11...8.668.89...
þ
2
1
logSFR1Myr)#!(12) 0.07#0.900.991.351.510.060.761.360.981.781.931.000.850.950.830.291.000.510.310.801.641.281.191.310.890.570.680.681.151.071.601.171.411.221.051.311.022.101.231.532.210.771.420.501.131.541.40
(
logM%(M)!(11) 11.1011.2311.2110.6810.3411.4010.5110.3610.9910.7310.9610.8410.9410.5811.3310.4610.2910.9411.0311.2110.299.959.749.7911.1411.0310.6310.8910.9010.5910.3310.0411.079.3911.4410.7810.3310.3011.309.9811.2111.2510.8210.989.799.9910.36
A1530(mag)(10) 3.551.793.752.481.446.021.361.392.332.031.952.611.622.262.140.781.792.941.100.530.900.810.480.331.514.561.492.332.051.431.530.623.030.232.132.691.041.513.120.483.021.731.961.201.160.58...
3222712332110334700698247 418042592047922825375
0000000000111000032201101 231211100100000011000
NUVmag)(9) 10.)30.)90.)20.)80.)10.)70.)80.)80.)30.)70.)60.)80.)80.)60.)90.)50.)90.)40.)00.)20.)00.)50.)00.)20.)...30.)30.)40.)50.)80.)90.)10.)80.)10.)50.)40.)10.)70.)30.)10.)70.)80.)80.)30.)70.)00.)
( 9857872026471570212367064 906771283656113882629
9.8.8.8.8.8.9.9.9.8.9.9.9.9.9.0.8.0.9.0.8.9.9.9.9. 9.0.9.9.9.9.9.8.9.9.7.8.9.9.9.8.9.0.9.9.7.
1111111111111112121211111 121111111111111112111
95466355433406682809607647157009955085755581629
00001000002120001222131021222331110301100112010
FUV(mag)(8) 860.)300.)020.)590.)410.)160.)740.)740.)420.)770.)300.)480.)520.)710.)020.)120.)450.)980.)350.)150.)970.)120.)040.)030.)780.)320.)250.)710.)940.)520.)250.)380.)300.)850.)740.)760.)850.)110.)370.)570.)970.)130.)550.)860.)130.)700.)050.)
0.9.9.9.9.8.9.9.9.8.0.9.9.9.0.0.8.9.9.0.8.0.9.0.9.9.9.9.9.0.0.9.9.8.9.0.7.9.9.9.9.9.9.9.0.9.8.
21111111112111221112121211111221111211111111211
Continued logI15302Lkpc)#!(7) 6.077.207.259.928.527.957.999.177.327.528.378.537.438.247.528.918.697.217.297.348.438.479.118.847.567.858.007.958.718.058.318.207.909.498.098.3610.259.167.469.018.937.407.948.828.679.478.97
— (
1
TABLE r50u;(kpc)(6) 54.4914.7413.950.853.4313.215.771.6620.1724.915.143.3612.464.9611.452.023.2114.1612.8412.414.533.321.742.7612.338.306.966.403.605.704.044.918.051.205.973.850.501.8712.723.242.2413.096.862.862.961.842.64
ogL1530(L)!(5) 10.3410.3310.3410.5810.3910.9910.3110.4110.7311.1110.5910.3810.4210.4310.4410.3210.5010.3110.3110.3310.5410.3110.3910.5210.5410.4910.4810.3610.6210.3610.3210.3810.5110.4510.4410.3310.4510.5010.4710.8310.4310.4310.4110.5310.4110.8010.61
l
edshift(4) 0.2850.1490.1340.2190.1670.1840.1770.1950.2380.2700.2930.1700.1800.1960.2260.2080.1250.1940.1500.2120.1620.2050.1420.2470.2270.1780.1710.1820.2610.2530.2190.1640.1810.1390.2020.2720.0910.1640.1790.2800.2180.1540.1790.2320.2290.2840.118
R
45564768878246829833644396482287994056595824950
40065081607306867523794927799337165957289069465
Decl.(deg)(3) 14.33113.47313.20812.9971.024#8.141#8.156#8.277#8.968#8.097#0.966#0.5176.635#7.335#7.000#7.421#8.069#1.036#1.1180.9660.471#0.132#1.1975.935#0.6420.0981.2491.1651.1390.9270.3965.420#6.301#5.111#37.73523.20039.81450.07049.38746.74946.58442.90041.29342.60246.21437.17943.622
73032374080584480969616921653670259033463860001
23629341800133376047776395689601499445670494027
R.A.(deg)(2) 0.3212.9813.0963.4524.1319.8570.1431.3732.1872.3894.9545.1345.5337.4487.8488.6179.8100.6161.2131.3471.9842.0952.1912.9343.2283.3453.8724.7794.8015.0906.0967.0329.8120.5365.7640.4182.1843.8474.0484.3434.6754.7454.8684.8875.2285.4056.054
33333344444444444555555555555555561222222222222
1111111111111
ObjID1) 04940..................15805..................08116..................41435..................45437..................63751..................94732..................98139..................18558..................91413..................64076..................78540..................95902..................40592..................87109..................43897..................60834..................54498..................71148..................02004..................15213..................51653..................29883..................86402..................17768..................12195..................50803..................44016..................44028..................40313..................91989..................21309..................22665..................78659..................75657..................14396..................67253..................99567..................00285..................10508..................54025..................11190..................51786..................83532..................83209..................84117..................73210..................
S( 02557454084967163956430267711291638415018664980
S 02758006363563696505301542122787769484507655046
D 22483442524214625436823099333650982462339070610
S 3788268215959512011215980695171201154203202642233692424242033123060052638212450146881845412345
39391774441087444111111410111114480368770636076
21215112225511222555555255555552210269740696086
44441774441577444115111415111514477585557888718
22223222223122222331333231333132220322220222032
77777777777077777770777770777077770777770777077
77777777777877777778777778777877778777778777877
88888888888888888888888888888888888888888888888
55555555555555555555555555555555555555555555555
446
)
H
O/
log((13) ...9.15...8.618.318.88...9.109.209.08...9.118.85...9.06.........8.919.049.05......9.11...8.868.988.46...8.779.108.868.708.819.11............9.068.259.119.008.63...8.60
þ
2
1
logSFR1Myr)#!(12) 2.05#1.710.820.521.410.801.091.431.060.880.17#0.991.610.990.901.370.531.271.270.910.771.990.571.280.580.850.750.720.642.460.890.981.001.361.051.641.030.920.241.100.491.072.351.351.260.82
(
logM%(M)!(11) 11.1310.9311.059.679.9110.7211.1510.6511.1511.0311.5310.8510.1511.2910.7411.0011.3111.0910.5611.0110.9010.5411.4711.1011.099.9711.189.2010.5510.5410.9810.269.7010.2110.8610.8811.009.8810.8210.619.4610.6810.789.5611.089.62
A1530(mag)(10) 2.111.221.530.440.301.352.792.392.242.85...2.701.002.802.432.214.552.501.781.762.342.222.303.150.841.362.280.461.450.342.870.900.411.621.551.712.64...1.952.200.561.481.740.892.610.19
375612808 087623171367870 6820 198722 7729 88
000000000 101000101101001 0001 100010 1010 00
NUVmag)(9) ...40.)10.)40.)30.)30.)60.)60.)00.)40.)...40.)30.)70.)40.)40.)90.)10.)60.)80.)10.)00.)80.)30.)00.)50.)...40.)90.)40.)20.)...60.)60.)50.)70.)60.)80.)...10.)90.)10.)10.)...70.)20.)
( 839976453 320202868781214 8136 834122 5937 22
7.8.7.8.7.9.9.6.9. 9.9.0.8.9.0.9.8.9.9.8.0.9.9.9. 8.9.9.9. 9.9.9.9.0.9. 0.8.0.9. 9.9.
111111111 112112111112111 1111 111121 2121 11
4738514616307644727593796760542837771433171752
2010100101021210021211211111102121112002122011
FUVmag)(8) 40.)30.)70.)10.)90.)70.)30.)80.)50.)10.)80.)80.)60.)00.)20.)20.)00.)50.)40.)30.)80.)70.)30.)10.)00.)80.)20.)60.)10.)70.)40.)50.)50.)40.)60.)60.)00.)90.)60.)70.)10.)20.)20.)40.)40.)90.)
( 2490513696458386645471696647459827872334972869
0.8.8.8.9.8.0.9.6.9.8.9.9.0.8.9.0.0.9.0.9.9.0.9.9.9.9.8.9.9.9.9.0.9.9.9.0.9.8.0.8.0.0.7.9.8.
2111112111111211221211211111111121112112122111
Continued logI15302Lkpc)#!(7) 7.548.257.438.308.828.957.448.278.327.727.527.708.797.567.648.836.497.798.817.207.549.657.167.937.219.657.969.917.316.947.547.718.988.917.748.377.199.608.267.969.048.028.519.607.738.82
— (
1
TABLE r50u;(kpc)(6) 10.024.3711.514.062.962.0711.084.743.9510.7932.039.682.589.729.052.2432.827.262.4314.4410.641.5316.566.2516.011.149.291.0312.6127.6811.448.151.982.768.385.7714.441.048.466.321.896.043.901.559.212.46
ogL1530(L)!(5) 10.3410.3310.3510.3110.5610.3810.3310.4210.3110.5811.3310.4710.4110.3310.3510.3310.3210.3110.3810.3210.3910.8210.4010.3210.4210.5610.6910.7310.3110.6210.4610.3310.3710.5910.3810.6910.3110.4310.9110.3610.3910.3810.4910.7810.4610.40
l
edshift(4) 0.2230.1030.1320.0840.2150.0970.2290.1930.0530.2200.2990.1950.2050.2260.1240.1710.2520.2370.1730.2370.1950.2350.2770.1910.1850.2220.2270.1810.1540.2260.2230.1880.2310.2340.1990.2620.2140.1730.1850.2490.1350.2830.2570.1300.1980.141
R
4694451275983599676494946105905660808095785726
3618575302330879421014799900807650139893403591
Decl.(deg)(3) 42.16938.00344.14340.71047.96447.17546.97745.25352.53345.56757.07645.62554.4775.3744.58655.3981.23242.75859.29148.64359.86145.15359.61056.27148.95354.81057.73844.46046.17559.00650.58246.42459.84842.78553.45754.36856.99361.66561.22247.39248.66156.43057.40551.58539.74257.534
5960218682354355907658622219328931026716468723
2818878029495607511304309926381034085394193087
R.A.(deg)(2) 6.0676.1386.7118.8839.3899.6150.7100.9111.5092.2513.4046.0726.6326.6737.0827.5997.8059.3549.4469.9500.0760.4970.6020.6500.6530.9011.1391.5011.6822.1822.3752.4633.4413.7863.9923.9997.0517.1027.1637.4087.9067.9268.1428.6448.7398.804
2222223333333333333344444444444444444444444444
1111111111111111111111111111111111111111111111
ObjID1) 76092..................88122..................00946..................66445..................95436..................56918..................74276..................36751..................92770..................59108..................26831..................56879..................23726..................27062..................16286..................96884..................44494..................90553..................88424..................57902..................21978..................82257..................51103..................12515..................20003..................86207..................35009..................13605..................43150..................44766..................10202..................10146..................98641..................23780..................55860..................89360..................47371..................83550..................81719..................84272..................19192..................14044..................74965..................13320..................21680..................06065..................
S( 1741340318200600889235405759053107298000281503
S 6665069104508523497008370431651257035364826496
D 7307025470789580517140061074413204267401837817
S 18574562685758130608229495281747294374311712124131680643176355016443245874696480905774941774
3868336373546000451152501378208818366116636446
9868113949504770908955509143503684933888813023
8181009858525227725151571053179152899551109259
2323110222232330232323203121302323200223310330
7777000777777770777777707070707777700777700770
7777888777777778777777787878787777788777788778
8888888888888888888888888888888888888888888888
5555555555555555555555555555555555555555555555
447
)
H
O/
log((13) ......9.13...9.08...9.06......9.07...8.76...9.15.........8.829.05......8.33...9.068.70...9.069.128.628.859.138.839.14...8.91...8.19...9.10...8.628.72......9.02......
þ
2
1
logSFR1Myr)#!(12) 0.550.861.041.081.331.700.730.640.651.220.311.020.810.930.660.430.550.850.821.090.621.100.601.941.420.702.101.071.131.671.451.151.371.031.340.670.511.110.710.970.941.710.690.170.820.960.93
(
logM%(M)!(11) 10.8511.2010.8711.0311.1311.0910.7811.0511.4010.7810.789.8411.0211.2111.4811.2311.2210.0811.0310.9611.249.9110.8111.0510.1310.9010.9910.829.5410.6411.049.5711.1911.1110.2310.958.9410.4011.0511.129.839.9910.9111.4010.6611.3110.65
A1530(mag)(10) 1.582.843.472.203.542.422.550.592.052.442.180.591.804.468.481.420.001.000.691.764.310.252.493.37...1.402.252.700.090.151.591.081.501.821.270.750.011.591.860.250.520.842.372.392.340.841.47
00933905680160909680 6037355592206322461 54 248
11011010101101010001 0110100000010110101 00 001
NUVmag)(9) 50.)20.)20.)80.)70.)80.)20.)50.)30.)00.)40.)80.)70.)30.)00.)30.)40.)60.)80.)30.)...10.)50.)60.)20.)00.)80.)70.)20.)20.)80.)00.)20.)00.)20.)70.)20.)70.)10.)70.)...80.)70.)...00.)30.)70.)
( 85703575147099757625 9907111621348426468 47 086
9.9.9.0.0.9.9.8.0.9.9.0.8.9.9.9.9.8.9.9. 8.9.0.8.0.8.8.8.9.9.9.9.8.0.0.9.0.8.9. 8.9. 9.9.9.
11122111211211111111 1121211111111221211 11 111
87022080254344940267827177993654332843011386463
11222211211212112111111211001100212202121100002
FUVmag)(8) 00.)80.)70.)70.)60.)10.)60.)60.)30.)60.)20.)00.)70.)30.)00.)40.)70.)50.)50.)60.)00.)30.)80.)40.)70.)30.)00.)70.)10.)90.)40.)50.)00.)90.)00.)00.)80.)90.)30.)00.)00.)60.)10.)20.)20.)70.)20.)
( 97133277354535140967018238542286923942706109414
9.9.0.0.0.0.9.8.0.9.9.0.9.0.0.9.0.8.9.9.0.9.9.0.9.9.8.8.9.9.9.9.9.9.0.0.9.0.8.0.8.9.0.9.9.0.9.
11222211211212212111211211111111112212121121121
Continued logI15302Lkpc)#!(7) 7.717.417.587.477.408.218.217.627.277.978.509.357.447.487.337.217.618.107.557.327.769.007.447.898.868.258.377.908.848.567.599.648.137.478.888.3110.779.027.717.579.369.317.467.477.767.7510.01
— (
1
TABLE r50u;(kpc)(6) 8.8412.829.2210.5012.815.264.5811.7315.287.013.321.2311.8210.9212.7914.239.545.6410.5612.457.572.1711.426.852.464.695.327.332.923.039.440.865.0211.112.244.040.381.988.3610.171.481.8910.9912.547.509.420.60
ogL1530(L)!(5) 10.4010.4210.3110.3110.4110.4510.3310.5610.4410.4610.3410.3310.3810.3510.3410.3110.3710.4010.4010.3110.3210.4710.3510.3610.4410.3910.6210.4310.5710.3210.3410.3110.3310.3610.3810.3210.7210.4110.3510.3810.5010.6610.3410.4610.3110.5010.37
l
edshift(4) 0.2050.2010.2110.2280.2520.2470.1810.1510.2550.1900.1580.2460.1610.2550.2110.1560.2140.1380.1850.1770.1970.1600.1940.2270.1730.1980.1450.1170.1860.1480.1890.1700.1910.1540.2380.2860.2410.2450.1200.2120.1330.1980.2030.2210.1540.2550.164
R
21198827002987210489505565779761647753679557855
68178446260626134326673183931619469111449132525
Decl.(deg)(3) 38.67057.82738.15656.59438.41855.12442.73344.11248.11047.70248.49163.41745.79057.11345.34460.22654.49651.10253.32852.87856.66648.74949.69552.86258.93362.65363.18765.55154.78956.81465.39666.10567.48558.13763.26262.91865.22863.15366.43564.20064.68466.8000.073#59.22859.27159.2890.523
69619863243262058165016767134488369187063905906
40442657244694685473520252957025235775453889340
R.A.(deg)(2) 9.2259.5809.8750.0930.1040.5032.1012.1642.5102.6292.7243.0463.5473.7303.9144.8925.7895.8586.0426.3046.5426.5587.3407.4377.7667.8238.3339.7659.8390.1570.6922.9395.0878.1739.5709.8073.2654.9490.2039.5979.8808.4829.9670.1170.1881.1122.500
44455555555555555555555555555666666677888016661
11111111111111111111111111111111111111111222223
ObjID1) 61363..................68126..................03546..................58909..................69282..................06501..................82971..................61656..................45580..................09127..................47490..................59876..................29906..................62459..................86075..................17353..................39661..................09644..................39624..................68688..................17989..................54188..................20184..................77714..................76243..................72903..................40350..................09441..................90084..................89559..................34723..................64802..................96047..................55636..................39594..................71613..................75234..................57702..................66387..................34987..................05821..................05291..................94109..................34103..................34081..................05123..................24833..................
S( 85676838010416987778132924597405645087721116659
S 36151422471449116092380155247335455036252708850
D 37767420175411759941571084848784979143193238826
S 6674955895714722595364693882258507908984205338070652571794607417906035945728647379289958586479
26363868333188560644838770054815185957177597774
53232384111843135800513830050385831013866585558
69595972222529291122223197752955599199588585550
10303293333232303333331300023222222120222242223
00707727777777707777770700077777777070777787777
88787787777777787777778788877777777878777787777
88888888888888888888888888888888888888888888888
55555555555555555555555555555555555555555555555
448
O/H) dforNUVmass
logSFR1(Myr)12log(#þ!(12)(13) 1.008.741.33...1.51...0.63...0.939.060.63...0.70...0.60...1.129.271.478.860.82...0.90...0.54...0.02...#1.37...1.158.650.928.821.069.161.568.680.50...0.788.610.649.061.618.960.948.990.45...0.538.221.049.070.948.621.598.89 ofFUVluminosity(correcteGalacticextinction).Col.(9):w.Col.(11):Logofstellar
logM%(M)!(11) 10.2511.2511.1511.1510.5611.4411.1611.3711.0610.1211.0811.0210.9710.5510.769.9710.1511.109.9210.859.3110.3310.5610.3710.599.5510.7110.0811.01 Col.(5):Logcorrectedforattenuationlaethod.
A1530(mag)(10) 1.091.264.226.372.252.373.080.000.851.320.711.092.193.273.290.670.652.190.76...0.731.481.172.363.090.271.070.742.32 pipeline.agnitude(starburst(2004)m
SSm1)al.
FUVNUV(mag)(mag)(8)(9) 19.780.2418.740.09))19.930.2419.850.14))19.720.3119.530.17))19.980.0819.760.04))19.720.1819.650.12))19.330.1419.840.16))19.760.1920.170.13))19.500.1919.160.13))20.110.2319.990.17))19.910.2219.240.11))20.350.2519.980.12))19.970.2319.380.15))19.140.2019.460.14))17.850.1017.720.06))20.180.2919.980.21))18.300.0917.840.04))18.660.0218.270.01))19.880.2019.750.13))19.270.0418.820.02))18.790.0319.630.03))20.320.0620.200.03))19.840.2420.030.18))19.560.1919.270.12))19.690.1919.600.10))19.870.2020.390.15))19.890.1920.030.14))20.130.2220.230.16))18.760.1218.380.06))20.530.2619.560.12)) 00.0).Col.(4):RedshiftfromSDGalacticextinction).Col.(8):FUVSSspectra,andtheCalzetti(200MetallicityusingtheTremontiet
1—TABLEContinued rlogIR.A.Decl.logL153050u1530;2(L)(kpc)(Lkpc)(deg)(deg)Redshift#!!(5)(6)(7)(2)(3)(4) 313.793400.317490.19810.412.528.81#315.197480.555890.25410.596.328.19315.849580.998810.17710.327.517.77317.708958.011800.21110.3921.746.92#322.769530.097790.17810.337.767.75322.893190.302880.21310.6610.847.79#323.278598.593990.21710.519.727.74#325.835330.251390.16910.3713.487.31326.069181.095510.24310.4811.417.57326.251071.199330.20410.390.779.82333.181249.003900.24710.4012.677.40#338.327947.737240.21010.3911.187.49#340.031079.631570.15410.4211.177.53#340.1599410.099330.08410.378.627.70#340.1852410.274530.25710.516.558.08#344.726569.342140.11610.503.408.64#346.765621.219780.12610.430.719.93347.517361.179080.20710.416.188.03349.554170.690600.25210.852.409.29#349.904420.228420.18510.7420.007.34351.413450.752000.27710.521.069.67353.216921.232790.18710.336.857.86353.463990.280750.19810.507.967.90354.302640.277630.21210.518.157.89354.411620.051340.18610.318.357.67358.448730.900610.22310.482.179.01358.578000.941670.23210.4211.387.51358.7063610.978450.12110.351.899.00#359.308620.145750.26210.387.697.81 1):SDSSObjectIDnumber.Col.(2):Rightascension(J2000.0).Col.(3):Declination(J20g-correctedhalf-lightradiusinuband.Col.(7):LogofFUVsurfacebrightness(correctedforextinction).Col.(10):FUVattenuationusingtheBalmerdecrementmeasuredontheSD12):Logofextinction-correctedstarformationratedeterminedviaSEDfitting.Col.(13):
SDSSObjID(1) 587730846887707478..................587730847962104313..................587730848499237044..................587727212271567298..................587730847428510324..................587730846891704703..................587727212273992007..................587731186725814690..................587731187799687683..................587731187799753015..................587726877808591211..................587726879958302970..................587726877811605723..................587726877274800314..................587730815752667321..................587730817365245979..................587731187808731205..................587731187809059012..................588015508191051903..................587731186736365813..................587731187273892048..................587731187811549347..................587731186737938564..................587731186738266349..................588015509266890925..................588015510342402184..................588015510342468082..................587727225152733191..................588015509269053589.................. UVLGsample.Col.(Notes.—Galacticextinction).Col.(6):Seeinmagnitude(correctedforGalacticdeterminedviaSEDfitting.Col.(
449
450 HOOPES ETAL. Vol. 173
Fig.4.—FUVsurfacebrightnessvs.FUVluminosityfor215UVLGsinthe Fig.5.—Half-lightradiusintheSDSSubandvs.FUVluminosityfor215UVLGs
GR1/DR3sample.FUVluminosity(L1530)isdefinedaskPkat15308.FUVsur- intheGR1/DR3sample.FUVluminosity(L1530)isdefinedaskPkat15308.The
ufa-cbeanbdrihgahltfn-leisgshtisraddeiufisn.ed as I1530¼L1530/(2#r520;u), where r50;u is the SDSS uouprpcehrodsoetntebdoluinnedasrhyobwestwaeceonnlsatragnetasnudrfcaocmepbarcigthUtnVeLssGos,fa1n0d8tLhe!lkopwce#r2d,owtthediclhinies
showsI 109L kpc 2,whichisthelowerboundaryofvaluesseenintypical
LBGsa1t5z30¼3(Giav!alisco#2002).
ThisimpliesthattheUVLGsspanasimilarlylargerangeofsize. ¼
ThisisconfirmedinFigure5,whichplotstheluminosityagainst
thehalf-lightradius.UVLGsrangeinhalf-lightradiusfrom<1to dergoingintensestarburststhataremuchmoresignificantthan
>20 kpc. The dotted lines in Figure 5 show a constant surface thepastaveragerateof starformation.TheFUVsurfacebright-
brightnessof108and109L kpc#2,thelatterbeingthelowerlimit nessappearstobeagoodindicatorofstarformationintensityfor
seeninLBGsatz 3(Gi!avalisco2002).Onlyafractionof the UV-selected galaxies. The typical colors of LBGs are also in-
¼
UVLGshavesurfacebrightnessesthatrivalthoseof LBGs,even dicated in the plot (Shapley et al. 2001; Papovich et al. 2001;
thoughtheyallhaveLBG-likeluminosities. Giavalisco2002).
TheFUVsurfacebrightnessisrelatedtothestarformationin- Figure7showstheFUVsurfacebrightnessversusthespecific
tensity,i.e.,thestarformationrateperunitarea.Figures4and5 starformationrate(starformationratenormalizedbystellarmass).
showthenthatonlyasubsetoftheUVLGsareluminousbecause The extinction-corrected star formation rates were determined
theyhavehighstarformationintensities.Therestowetheirhigh by SED model fitting. We have also calculated star formation
luminositiestotheirlargesize;i.e.,theyhavemodestlevelsof ratesusingtheH!luminosityintheSDSSspectrausingtherec-
starformationintensityspreadoveralargearea. ipegiveninKennicutt(1998);thesevaluesgenerallyagreewithin
This is also apparent inFigure 3, which shows more clearly afactorof 2,whichisquitegoodconsideringthattheH! mea-
thecorrelationbetweensurfacebrightnessandstellarmassnoted surementsweretakenthrough3 fibers.Thespecificstarforma-
00
above. The UVLGs with low surface brightness are the most tionraterelatesthecurrenttopaststarformation,andtheinverse
massive,whilethehighsurfacebrightnessUVLGsarelow-mass of thisquantityisthe‘‘galaxybuildingtime,’’thetimeitwould
systems.ThetypicalmassandsurfacebrightnessrangeofLBGs taketobuildupthecurrentstellarmassatthecurrentSFR.The
isshowninthefigure(Shapleyetal.2001;Papovichetal.2001; specificstarformationrateisclearlycorrelatedwiththeFUVsur-
Giavalisco 2002). Figures 3Y5 illustrate the fact that UVLGs facebrightness,withthehighsurfacebrightnesssystemsgener-
spanacontinuousrangeof properties;i.e.,thereisnoclearde- ally having the highest specific SFRs and short building times,
marcationbetweenthelargeandcompactsamples.Thedivision indicatingthatthesearestarburstsystems.ThelargeUVLGshave
ofthesamplesatasurfacebrightnessofI1530 >108L kpc#2is galaxybuildingtimesofroughlyaHubbletime,asexpectedfora
anarbitraryboundary. ! galaxy that has been built up over the age of the universe at a
constantorslowlyvaryingrateofstarformation.Galaxybuilding
4.2. Star Formation and Attenuation by Dust
timesoflessthan1GyraretypicalforLBGs(Shapleyetal.2001;
Figure6showstheFUV-rcolorandNUV-rcolorforthe215 Papovich et al. 2001; Giavalisco 2002), and the high surface
UVLGsasafunctionofsurfacebrightness.Bothcolorsarewell brightnessUVLGsoverlapthisrange.However,someofthehigh
correlatedwithsurfacebrightness,withthebrightestgalaxieshav- surfacebrightnesssystemshavelowerspecificSFRsandlonger
ingthebluestcolor.ThisagreeswiththeideathattheUV-optical buildingtimesthantypicalLBGs,whichsuggeststhattheyhave
colorsaresensitivetotheratioof currenttopaststarformation. hadsignificantstarformationpriortothecurrentburst.Spitzer
Salimetal.(2005)showedthattheNUV-rinparticularisagood imagingofLBGsindicatesthattheydonothavesignificantpop-
tracerofthestarformationrateparameterb,whichisthecurrent ulationsofolderstars(Barmbyetal.2004),suggestingthatLBGs
SFRdividedbythepast-averageSFR.Thebluecolorofthehigh areundergoingtheirfirstmajorburstof starformation.Ifthisis
surface brightness UVLGs can be understood if they are un- thecase,thenthesesystemswithlongerbuildingtimesmaynot