J/A+A/550/A41ivo://CDS.VizieR/J/A+A/550/A41doi:10.26093/cds/vizier.35500041CDSCombes F.Garcia-Burillo S.Braine J.Schinnerer E.Walter F.Colina L.2018-01-30T07:18:24Z2013-01-24T08:36:48ZCDS support team

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

cds-question@unistra.frgalaxiesradio-galaxiesspectroscopyAfter new observations of 39 galaxies at z=0.6-1.0 obtained at the IRAM 30m telescope, we present our full CO line survey covering the redshift range 0.2<z<1. Our aim is to determine the driving factors accounting for the steep decline in the star formation rate during this epoch. We study both the gas fraction, defined as Mgas/(Mgas+Mstar), and the star formation efficiency (SFE) defined by the ratio between far-infrared luminosity and molecular gas mass (L_FIR_/M(H_2_), i.e. a measure for the inverse of the gas depletion time. The sources are selected to be ultra-luminous infrared galaxies (ULIRGs), with L_FIR_ greater than 10^12^L_{sun}_, and experiencing starbursts. When we adopt a standard ULIRG CO-to-H_2_ conversion factor, their molecular gas depletion time is less than 100Myr. Our full survey has now filled the gap of CO observations in the 0.2<z<1 range covering almost half of cosmic history. The detection rate in the 0.6<z<1 interval is 38% (15 galaxies out of 39), compared to 60% for the 0.2<z<0.6 interval. The average CO luminosity is L'_CO_=1.8x10^10^K.km/s.pc^2^, corresponding to an average H_2_ mass of 1.45x10^10^M_{sun}_. From observation of 7 galaxies in both CO(2-1) and CO(4-3), a high gas excitation has been derived; together with the dust mass estimation, this supports the choice of our low ULIRG conversion factor between CO luminosity and H_2_ for our sample sources. We find that both the gas fraction and the SFE significantly increase with redshift, by factors of 3+/-1 from z=0 to 1, and therefore both quantities play an important role and complement each other in cosmic star formation evolution.2013A&A...550A..41Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/550/A41CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/550/A41https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/550/A41http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/550/A41https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/550/A41https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/550/A41http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/550/A41GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/550/A41/table1 (Source sample, with list of spectra)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/550/A41/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/550/A41/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/550/A41/table1?GETtext/xml+votable180.050000true12.540833-0.6502780.0055555555555555566/4886 5242 5690 5974 6444 7329 8520 8789 9077 9144 9149 9397 9502 10153 10155 10191 10212 10877 11073 11274 11428 11498 11607 17742 17758 17831 17838 18024 18125 19088 21855 25950 272909.276497240453405e-25 3.3107421909657627e-21https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/550/A41?format=asciiRadiodefaultJ/A+A/550/A41/table1Source sample, with list of spectrarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalSource namemeta.id;meta.maincharprimaryNameGalaxy namemeta.idcharRAJ2000Right Ascension J2000pos.eq.ra;meta.mainDEJ2000Declination J2000pos.eq.dec;meta.mainzRedshiftsrc.redshiftfloatSp1[1/21]? First spectrum number (1)meta.id;meta.fileintnullableCO1CO line transition (2-1), (3-2) or (4-3)meta.id;phys.atmol.transitioncharsp1Plot of spectrummeta.ref.urlcharSp2[1/21]? Second spectrum number (1)meta.id;meta.fileintnullableCO2CO line transition (4-3)meta.id;phys.atmol.transitioncharsp2Plot of spectrummeta.ref.urlcharJ/A+A/550/A41/table2Observed line parametersrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGalSource namemeta.id;meta.maincharLineObserved line: CO(2-1), (3-2) or (4-3)meta.id;phys.atmol.transitioncharnuOnserved frequencyGHzem.freqfloatl_S(CO)Limit flag on S(CO)numeta.code.errorcharS(CO)CO flux density (1)Jy.km/sphot.fluxfloate_S(CO)? rms uncertainty on S(CO) (2)Jy.km/sstat.errorfloatnullableV? Velocity is relative to the optical redshift given in Table 1km/sphys.veloc;arith.diffintnullablee_V? rms uncertainty on V (2)km/sstat.error;pos.cartesian.yintnullableDVFWHM? V_FWHM_ differencekm/sphys.angSizeintnullablee_DVFWHM? rms uncertainty on DVFWHM (2)km/sstat.errorintnullablel_L'COLimit flag on L'COmeta.code.errorcharL'COCO luminosity1e+10K.km.s**-1.pc**-2phys.luminosity;em.radiofloatS60? 60um flux density (3)Jyphot.flux.density;em.IR.30-60umfloatnullablen_S60[e] Note on S60 (6)meta.notecharl_S100Limit flag on S100meta.code.errorcharS100? 100um flux density (3)Jyphot.flux.density;em.IR.60-100umfloatnullablen_S100[e] Note on S100 (6)meta.notecharlogFIR? FIR luminosity (4)log(solLum)phys.luminosity;em.IRfloatnullableF1.4GHz? 1.4GHz flux (5)mJyphot.flux.density;em.radio.750-1500MHzfloatnullablelogM*? Stellar masslog(solMass)phys.massfloatnullablen_logM*[gh] Note on logM* (6)meta.notechar