J/ApJ/853/87ivo://CDS.VizieR/J/ApJ/853/87doi:10.26093/cds/vizier.18530087CDSRigby J.R.Bayliss M.B.Chisholm J.Bordoloi R.Sharon K.,Gladders M.D.Johnson T.Paterno-Mahler R.Wuyts E.Dahle H.,Acharyya A.2019-03-06T07:56:31Z2019-02-07T09:35:48ZCDS support team

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

cds-question@unistra.frgalaxiesgravitational-lensingvisible-astronomyspectroscopyultraviolet-astronomyWe stack the rest-frame ultraviolet spectra of N=14 highly magnified gravitationally lensed galaxies at redshifts 1.6<z<3.6. The resulting new composite spans 900<{lambda}_rest_<3000{AA}, with a peak signal-to-noise ratio (S/N) of 103 per spectral resolution element (~100km/s). It is the highest S/N, highest spectral resolution composite spectrum of z~2-3 galaxies yet published. The composite reveals numerous weak nebular emission lines and stellar photospheric absorption lines that can serve as new physical diagnostics, particularly at high redshift with the James Webb Space Telescope (JWST). We report equivalent widths to aid in proposing for and interpreting JWST spectra. We examine the velocity profiles of strong absorption features in the composite, and in a matched composite of z~0 COS/HST galaxy spectra. We find remarkable similarity in the velocity profiles at z~0 and z~2, suggesting that similar physical processes control the outflows across cosmic time. While the maximum outflow velocity depends strongly on ionization potential, the absorption-weighted mean velocity does not. As such, the bulk of the high- ionization absorption traces the low-ionization gas, with an additional blueshifted absorption tail extending to at least -2000km/s. We interpret this tail as arising from the stellar wind and photospheres of massive stars. Starburst99 models are able to replicate this high-velocity absorption tail. However, these theoretical models poorly reproduce several of the photospheric absorption features, indicating that improvements are needed to match observational constraints on the massive stellar content of star-forming galaxies at z~2.2018ApJ...853...87Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/853/87CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/hst : HST Archived Exposures Catalog (STScI, 2007)J/A+AS/103/97 : Grids of stellar models V. (Meynet+ 1994)J/ApJ/794/156 : MgII/FeII absorption profile for 0.3<z<1.4 gal. (Rubin+, 2014)J/AJ/155/104 : MEGaSaURA. I. The sample and the spectra (Rigby+, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/853/87https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/853/87http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/853/87https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/853/87https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/853/87http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/853/87GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapUVOpticaldefaultJ/ApJ/853/87/megas99*MEGaSaURA MagE/Magellan spectra of z=1.6-3.6 gravitationally-lensed galaxies; S99 modelsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[912.1/2999.5] Rest wavelength, vacuum Angstroms (1)0.1nmem.wlfloatFweightavg[-24.3/247.1]? Weighted average of normalized flux (2)phot.flux;arith.ratiodoublenullablee_Fweightavg[0/0.9] Uncertainty on fweightavgstat.errordoubleFmed[-0.4/110.2]? Median of normalized flux (2)phot.flux;stat.mediandoublenullableNgal[0/13] Number of galaxies in the stack at this wavelengthmeta.numberintstdFjack[0.0001/255]? Standard deviation from jackknife variancestat.stdevdoublenullableJ/ApJ/853/87/cosr3300R=3300 stacks of COS/HST spectra of z~0 galaxiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[1145.4/1753] Rest wavelength, vacuum Angstroms (1)0.1nmem.wldoubleFweightavg[0.004/1.6] Weighted average of normalized flux (2)phot.flux;arith.ratiodoublee_Fweightavg[0.01/0.2] Uncertainty on fweightavgstat.errordoubleFmed[-0.07/8.1] Median of normalized flux (2)phot.flux;stat.mediandoubleNgal[2/40] Number of galaxies in the stack at this wavelengthmeta.numberintstdFjack[0.001/3.1] Standard deviation from jackknife variancestat.stdevdoubleJ/ApJ/853/87/cosmaxrNative spectral resolution stacks of COS/HST spectra of z~0 galaxiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[1145.4/1753] Rest wavelength, vacuum Angstroms (1)0.1nmem.wldoubleFweightavg[0.004/1.6] Weighted average of normalized flux (2)phot.flux;arith.ratiodoublee_Fweightavg[0.01/0.2] Uncertainty on fweightavgstat.errordoubleFmed[-0.07/8.1] Median of normalized flux (2)phot.flux;stat.mediandoubleNgal[2/40] Number of galaxies in the stack at this wavelengthmeta.numberintstdFjack[0.001/3.1] Standard deviation from jackknife variancestat.stdevdoubleJ/ApJ/853/87/megapivotMEGaSaURA MagE/Magellan spectra of z=1.6-3.6 gravitationally-lensed galaxies; lambda pivot normalized stackrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[912.1/2999.5] Rest wavelength, vacuum Angstroms (1)0.1nmem.wlfloatFweightavg[-24.3/247.1]? Weighted average of normalized flux (2)phot.flux;arith.ratiodoublenullablee_Fweightavg[0/0.9] Uncertainty on fweightavgstat.errordoubleFmed[-0.4/110.2]? Median of normalized flux (2)phot.flux;stat.mediandoublenullableNgal[0/13] Number of galaxies in the stack at this wavelengthmeta.numberintstdFjack[0.0001/255]? Standard deviation from jackknife variancestat.stdevdoublenullableJ/ApJ/853/87/megashapeMEGaSaURA MagE/Magellan spectra of z=1.6-3.6 gravitationally-lensed galaxies; shape-normalized stackrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[912.1/2999.5] Rest wavelength, vacuum Angstroms (1)0.1nmem.wlfloatFweightavg[-24.3/247.1]? Weighted average of normalized flux (2)phot.flux;arith.ratiodoublenullablee_Fweightavg[0/0.9] Uncertainty on fweightavgstat.errordoubleFmed[-0.4/110.2]? Median of normalized flux (2)phot.flux;stat.mediandoublenullableNgal[0/13] Number of galaxies in the stack at this wavelengthmeta.numberintstdFjack[0.0001/255]? Standard deviation from jackknife variancestat.stdevdoublenullable