J/ApJ/765/47ivo://CDS.VizieR/J/ApJ/765/47doi:10.26093/cds/vizier.17650047CDSNestor D.B.Shapley A.E.Kornei K.A.Steidel C.C.Siana B.2017-12-12T14:45:17Z2014-11-26T07:29:38ZCDS support team

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

cds-question@unistra.frgalaxiesspectroscopyredshiftedapparent-magnitudeultraviolet-astronomyWe investigate the contribution of star-forming galaxies to the ionizing background at z~3, building on previous work based on narrowband (NB3640) imaging in the SSA22a field. We use new Keck/LRIS spectra of Lyman break galaxies (LBGs) and narrowband-selected Ly{alpha} emitters (LAEs) to measure redshifts for 16 LBGs and 87 LAEs at z>3.055, such that our NB3640 imaging probes the Lyman-continuum (LyC) region. When we include the existing set of spectroscopically confirmed LBGs, our total sample with z>3.055 consists of 41 LBGs and 91 LAEs, of which 9 LBGs and 20 LAEs are detected in our NB3640 image. With our combined imaging and spectroscopic data sets, we critically investigate the origin of NB3640 emission for detected LBGs and LAEs. We remove from our samples three LBGs and three LAEs with spectroscopic evidence of contamination of their NB3640 flux by foreground galaxies and statistically model the effects of additional, unidentified foreground contaminants. The resulting contamination and LyC-detection rates, respectively, are 62%+/-13% and 8%+/-3% for our LBG sample, and 47%+/-10% and 12%+/-2% for our LAE sample. The corresponding ratios of non-ionizing UV to LyC flux density, corrected for intergalactic medium (IGM) attenuation, are 18.0^+34.8^_-7.4_ for LBGs and 3.7^+2.5^_-1.1_ for LAEs. We use these ratios to estimate the total contribution of star-forming galaxies to the ionizing background and the hydrogen photoionization rate in the IGM, finding values larger than, but consistent with, those measured in the Ly{alpha} forest. Finally, the measured UV to LyC flux-density ratios imply model-dependent LyC escape fractions of f^LyC^_esc_~5%-7% for our LBG sample and f^LyC^_esc_~10%-30% for our fainter LAE sample.2013ApJ...765...47Nhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/765/47CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/418/2074 : Robust sample of galaxies at 6.0<z<8.7 (Mclure+, 2011)J/ApJ/736/31 : HETDEX pilot survey. II. 1.9<z<3.8 LAEs (Blanc+, 2011)J/ApJ/736/18 : Lyman-continuum emission in SSA22 field (Nestor+, 2011)J/MNRAS/401/1521 : Lyman break galaxies stellar masses at z~3 (Magdis+, 2010)J/ApJS/176/301 : Subaru/XMM-Newton deep survey IV. (SXDS) (Ouchi+, 2008)J/ApJ/667/79 : Ly{alpha} emission-line galaxies at z=3.1 (Gronwall+, 2007)J/ApJ/592/728 : Lyman break galaxies at redshift z~3 (Steidel+, 2003)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/765/47https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/765/47http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/765/47https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/765/47https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/765/47http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/765/47GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/765/47/table3 (Summary of Ly{alpha} emitters (LAEs) data)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/765/47/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/765/47/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/765/47/table3?GETtext/xml+votable180.050000true334.3850.19280560.005555555555555556Cone search capability for table J/ApJ/765/47/table1 (z>3.055 Lyman break galaxies (LBGs) sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/765/47/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/765/47/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/765/47/table1?GETtext/xml+votable180.050000true334.38554170.18261110.0055555555555555566/19033 190362.762881831355591e-19 3.3785437584409506e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/765/47?format=asciiUVOpticaldefaultJ/ApJ/765/47/table3Summary of Ly{alpha} emitters (LAEs) datal_RmagLimit flag on Rmagmeta.code.errorcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/130] Running sequence number (<[NSS2011] NNN> in Simbad)meta.id;meta.mainintLBGObject also identified as LBGmeta.id.crosscharf_Seq[e] Previsouly known source (1)meta.codecharRAJ2000[22] Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000[00] Degree of declination (J2000)pos.eq.dec;meta.mainRmag[23.9/27] R-band magnitudemagphot.mag;em.opt.Rfloatl_NB3640Limit flag on NB3640meta.code.errorcharNB3640[24.7/27.3] NB3640 (LyC) magnitudemagphot.mag;em.opt.Ufloatf_NB3640[fh] NB3640 is not LyC (1)meta.codecharOff[0.1/2.2]? Spatial offset between the centroids of R and NB3640 emissionarcsecpos;arith.difffloatnullablef_Off[j] Offset from BV detection (1)meta.codecharOffA[0/1.8]? Spatial offset between the centroids of Ly{alpha} and NB3640 emissionarcsecpos;arith.difffloatnullablel_FUV/FLyLimit flag on FUV/FLymeta.code.errorcharFUV/FLy[0.5/23]? Observed ratio in non-ionizing UV and LyC flux densities (G1)phot.flux;arith.ratiofloatnullablee_FUV/FLy[0.2/5.1]? FUV/FLy uncertaintystat.errorfloatnullablezem[3.04/3.12]? Spectroscopic redshift based on the observed wavelength of Ly{alpha} emissionsrc.redshiftfloatnullablef_zem[gi] LRIS spectroscopic observation (1)meta.codecharSimbadSimbad column added by the CDSmeta.refcharNEDSimbad column added by the CDSmeta.refcharJ/ApJ/765/47/table1z>3.055 Lyman break galaxies (LBGs) samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintLBGLyman-Break Galaxy identification (<SAS-LBG SSA22a-AANN> in Simbad)meta.id;meta.maincharf_LBG[f] Redshift not available (1)meta.codecharRAJ2000[22] Hour of right ascension (J2000)pos.eq.ra;meta.mainDEJ2000[00] Degree of declination (J2000)pos.eq.dec;meta.mainzem[3/3.4]? Ly{alpha} emission redshiftsrc.redshiftfloatnullablezabs[3/3.4]? Interstellar absorption redshiftsrc.redshiftfloatnullableRmag[23.4/25.9] R-band magnitudemagphot.mag;em.opt.RfloatNB3640[25.2/27]? NB3640 (LyC) magnitudemagphot.mag;em.opt.Ufloatnullablef_NB3640[e] Foreground object (1)meta.codecharOff[0.1/2]? Spatial offset between the centroids of the R-band and NB3640 emissionarcsecpos;arith.difffloatnullablel_FUV/FLyLimit flag on FUV/FLymeta.code.errorcharFUV/FLy[2/29.2]? Observed ratio in non-ionizing UV and LyC flux densities (G1)phot.flux;arith.ratiofloatnullablee_FUV/FLy[0.4/5.1]? FUV/FLy uncertaintystat.errorfloatnullableSimbadSimbad column added by the CDSmeta.ref.urlcharNEDSimbad column added by the CDSmeta.refchar