J/ApJ/745/173ivo://CDS.VizieR/J/ApJ/745/173doi:10.26093/cds/vizier.17450173CDSWelty D.E.Xue R.Wong T.2017-06-19T07:57:45Z2013-09-05T08:29:12ZCDS support team

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

cds-question@unistra.frmagellanic-cloudsinterstellar-mediumultraviolet-astronomyWe have determined column densities of H I and/or H_2_ for sight lines in the Magellanic Clouds from archival Hubble Space Telescope and Far-Ultraviolet Spectroscopic Explorer spectra of H I Ly{alpha} and H_2_Lyman-band absorption. Together with some similar data from the literature, we now have absorption-based N(H I) and/or N(H_2_) for 285 Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) sight lines (114 with a detection or limit for both species) - enabling more extensive, direct, and accurate determinations of molecular fractions, gas-to-dust ratios, and elemental depletions in these two nearby, low-metallicity galaxies. For sight lines where the N(H I) estimated from 21 cm emission is significantly higher than the value derived from Ly{alpha} absorption (presumably due to emission from gas beyond the target stars), integration of the 21 cm profile only over the velocity range seen in Na I or H_2_absorption generally yields much better agreement. Conversely, N(21 cm) can be lower than N(Ly{alpha}) by factors of 2-3 in some LMC sight lines - suggestive of small-scale structure within the 21 cm beam(s) and/or some saturation in the emission. The mean gas-to-dust ratios obtained from N(H_tot_)/E(B-V) are larger than in our Galaxy, by factors of 2.8-2.9 in the LMC and 4.1-5.2 in the SMC - i.e., factors similar to the differences in metallicity. The N(H_2_)/E(B-V) ratios are more similar in the three galaxies, but with considerable scatter within each galaxy. These data may be used to test models of the atomic-to-molecular transition at low metallicities and predictions of N(H_2_) based on comparisons of 21 cm emission and the IR emission from dust.2012ApJ...745..173Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/745/173CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/hst : HST Archived Exposures Catalog (STScI, 2007)II/236 : UBVR CCD survey of the Magellanic clouds (Massey+, 2002)II/187 : 30 Doradus OB Associations (Parker 1992)V/13 : Probable Members of the SMC (Azzopardi+ 1975, 1979)III/147 : Studies of LMC stellar content (Rousseau+ 1978)J/PASP/121/634 : FUSE observations in Magellanic Clouds (Blair+, 2009)J/A+A/456/623 : VLT-FLAMES survey of massive stars (Evans+, 2006)J/AJ/121/891 : UBV photometry of LMC OB associations (Parker+, 2001)J/AJ/119/2214 : Photometry of Magellanic OB associations (Massey+, 2000)J/MNRAS/306/279 : UBV photometry of LMC fg stars III (Schmidt-Kaler+ 1999)J/AJ/117/206 : LMC far-ultraviolet imaging (Brosch+, 1999)J/AJ/117/2244 : HST color-magnitude diagrams of the LMC (Olsen, 1999)J/AJ/118/1684 : UBV photometry of 4 LMC compact OB groups (Walborn+, 1999)J/AJ/103/1205 : Stellar Content of LH 9 and 10 in the LMC (Parker+ 1992)J/A+AS/30/261 : UBV and RVs of SMC Supergiants (Ardeberg+, 1977)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/745/173https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/745/173http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/745/173https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/745/173https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/745/173http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/745/173GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/745/173/slines (SMC and LMC sight lines })https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/745/173/slines?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/745/173/slines?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/745/173/slines?GETtext/xml+votable180.050000true11.26375-72.6994440.0055555555555555565/8274 8275 8280 8326 6/32958 33047 33048 33051 33053 33054 33055 33076 33078 33079 33085 33090 33091 33092 33094 33095 33106 33107 33112 33113 33115 33116 33126 33127 33128 33294 33295 33297 33298 33299 33316 33317 33319 333283.322582951404819e-19 3.852589004194616e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/745/173?format=asciiUVdefaultJ/ApJ/745/173/refsReferencesCommCommentmeta.notecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference codemeta.noteintBibCodeBibcodemeta.bib.bibcodecharAutAuthor's name(s)meta.bib.authorcharJ/ApJ/745/173/slinesSMC and LMC sight lines }SimbadNameSimbad column added by the CDSmeta.idcharStar? Star namemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMCSimbad column added by the CDSmeta.id.parentcharOName? Other name (1)meta.idcharReg[2w]? Region (2=LMC2; w=stars in "wing" region of SMC)obs.fieldcharRAJ2000Right ascension J2000pos.eq.ra;meta.mainDEJ2000Declination J2000pos.eq.dec;meta.mainVmag[9.5/21.6]? V-band magnitude (2)magphot.mag;em.opt.VfloatnullableB-V[-0.3/0.5]? B-V color index (2)magphot.color;em.opt.B;em.opt.VfloatnullableE(B-V)t[0/0.8]? E(B-V) (total) (3)magphys.absorptionfloatnullableE(B-V)L[-0.1/0.8]? E(B-V) (LMC) (3)magphys.absorptionfloatnullableSpT? MK spectral typesrc.spTypecharr_SpT? Reference for SpT (see refs.dat file)meta.ref;pos.frameintnullablel_N(HI)Limit flag on N(HI)meta.code.errorcharN(HI)? log(column density) from Lyman-{alpha} or Lyman-{beta} absorptionlog(cm**-2)phys.columnDensityfloatnullabler_N(HI)? Reference for N(HI) (see refs.dat file)meta.ref;pos.frameintnullablel_N(H2)Limit flag on N(H2)meta.code.errorcharN(H2)? log(H_2_ column density) from Lyman-band absorptionlog(cm**-2)phys.columnDensityfloatnullablef_N(H2)Flags about N(H2) uncertainty (4)meta.codecharr_N(H2)? Reference for N(H2) (see refs.dat file)meta.ref;pos.frameintnullableT01? H_2_ rotational temperature T01(H2) from N(J=1)/N(J=0)Kphys.temperatureintnullablel_N21Limit flag on N21meta.code.errorcharN21? log(HI column density) from 21cm emission (ATCA+Parkes)log(cm**-2)phys.columnDensityfloatnullableTpk[3/158]? Peak 21cm brightness temperatureKphys.temperature;stat.maxintnullableM02Cross-match with the UBVR CCD survey of the Magellanic clouds from Massey P., 2002, Cat. II/236, within 3"meta.ref.urlintnullable