J/A+A/590/A27ivo://CDS.VizieR/J/A+A/590/A27doi:10.26093/cds/vizier.35900027CDSGrossiM.CorbelliE.BizzocchiL.GiovanardiC.Bomans D.,Coelho B.De Looze I.Goncalves T.S.Hunt L.K.Leonardo E.Madden S.,Menendez-Delmestre K.Pappalardo C.Riguccini L.2017-12-12T14:44:47Z2016-05-12T09:20:05ZCDS support team

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

cds-question@unistra.frgalaxy-clustersgalaxiesspectroscopyco-line-emissionWe present ^12^CO(1-0) and ^12^CO(2-1) observations of a sample of 20 star-forming dwarfs selected from the Herschel Virgo Cluster Survey, with oxygen abundances ranging from 12+log(O/H)~8.1 to 8.8. CO emission is observed in ten galaxies and marginally detected in another one. CO fluxes correlate with the FIR 250um emission, and the dwarfs follow the same linear relation that holds for more massive spiral galaxies extended to a wider dynamical range. We compare different methods to estimate H_2_ molecular masses, namely a metallicity-dependent CO-to-H_2_ conversion factor and one dependent on H-band luminosity. The molecular-to-stellar mass ratio remains nearly constant at stellar masses <=10^9^M_{sun}_, contrary to the atomic hydrogen fraction, M_HI_/M*, which increases inversely with M*. The flattening of the M_H2_/M* ratio at low stellar masses does not seem to be related to the effects of the cluster environment because it occurs for both HI-deficient and HI-normal dwarfs. The molecular-to-atomic ratio is more tightly correlated with stellar surface density than metallicity, confirming that the interstellar gas pressure plays a key role in determining the balance between the two gaseous components of the interstellar medium. Virgo dwarfs follow the same linear trend between molecular gas mass and star formation rate as more massive spirals, but gas depletion timescales, tau_dep, are not constant and range between 100Myr and 6Gyr. The interaction with the Virgo cluster environment is removing the atomic gas and dust components of the dwarfs, but the molecular gas appears to be less affected at the current stage of evolution within the cluster. However, the correlation between HI deficiency and the molecular gas depletion time suggests that the lack of gas replenishment from the outer regions of the disc is lowering the star formation activity.2016A&A...590A..27Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/590/A27CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toVII/266 : Atlas of Virgo galaxies (McDonald+ 2011)J/AJ/90/1681 : The Virgo Cluster Catalog (VCC) (Binggeli+, 1985)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/590/A27https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/590/A27http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/590/A27https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/590/A27https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/590/A27http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/590/A27GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/590/A27/table1 (Main properties of the Virgo SFDs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/590/A27/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/590/A27/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/590/A27/table1?GETtext/xml+votable180.050000true182.353987513.57473890.0055555555555555566/26301-26302 26362-26363 27670 27677 27712 27714-27715 27729 27731 27770 27772 27858 27860 27869 27937 27946https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/590/A27?format=asciiOpticalRadiodefaultJ/A+A/590/A27/table1Main properties of the Virgo SFDsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameNamemeta.id;meta.maincharlogM*Stellar masslog(solMass)phys.massfloate_logM*rms uncertainty on logM*log(solMass)stat.errorfloatlogMHIHI masslog(solMass)phys.massfloate_logMHIrms uncertainty on logMHIlog(solMass)stat.errorfloatlogMdDust masslog(solMass)phys.massfloatlogSFRStar formation ratelog(solMass.yr**-1)phys.SFRfloate_logSFRrms uncertainty on logSFRlog(solMass.yr**-1)stat.error;phys.SFRfloat12+log(O/H)Abundance 12+log(O/H)phys.abundfloate_12+log(O/H)rms uncertainty on 12+log(O/H)stat.errorfloatn_12+log(O/H)[b] Mote on 12+log(O/H) (1)meta.notecharDefHIHI deficiency parameterstat.fit.paramfloatDVHIHI line FWHMkm/sspect.line.widthintn_DVHI[a] Note on DVHI (1)meta.notecharDistDistanceMpcpos.distancefloata25Isophotal major diameter at the 25th B-magnitude/arcsec^2^arcsecphys.angSizefloatb25Isophotal minor diameter at the 25th B-magnitude/arcsec^2^arcsecphys.angSizefloatSpCO10aCO(1-0) spectrum filename in subdirectory spmeta.id;meta.filecharSpCO21aCO(2-1) spectrum filename in subdirectory spmeta.id;meta.filecharSpCO10bCO(1-0) spectrum filename in subdirectory spmeta.id;meta.filecharSpCO21bCO(2-1) spectrum filename in subdirectory spmeta.id;meta.filecharSpCO10cCO(1-0) spectrum filename in subdirectory spmeta.id;meta.filecharSpCO21cCO(2-1) spectrum filename in subdirectory spmeta.id;meta.filecharSpCO10dCO(1-0) spectrum filename in subdirectory spmeta.id;meta.filecharSpCO21dCO(2-1) spectrum filename in subdirectory spmeta.id;meta.filecharSpCO10eCO(1-0) spectrum filename in subdirectory spmeta.id;meta.filecharSpCO21eCO(2-1) spectrum filename in subdirectory spmeta.id;meta.filecharCO10aShow the CO(1-0) spectrummeta.ref.urlcharCO21aShow the CO(2-1) spectrummeta.ref.urlcharCO10bShow the CO(1-0) spectrummeta.ref.urlcharCO21bShow the CO(2-1) spectrummeta.ref.urlcharCO10cShow the CO(1-0) spectrummeta.ref.urlcharCO21cShow the CO(2-1) spectrummeta.ref.urlcharCO10dShow the CO(1-0) spectrummeta.ref.urlcharCO21dShow the CO(2-1) spectrummeta.ref.urlcharCO10eShow the CO(1-0) spectrummeta.ref.urlcharCO21eShow the CO(2-1) spectrummeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlchar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.main