J/ApJ/808/136ivo://CDS.VizieR/J/ApJ/808/136doi:10.26093/cds/vizier.18080136CDSDonovan Meyer J.Peek J.E.G.Putman M.Grcevich J.2018-07-09T08:01:55Z2017-11-09T08:17:32ZCDS support team

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

cds-question@unistra.frdiffuse-molecular-cloudsh-i-line-emissionultraviolet-photometryWe present ultraviolet (UV) follow-up of a sample of potential dwarf galaxy candidates selected for their neutral hydrogen (HI) properties, taking advantage of the low UV background seen by the GALEX satellite and its large and publicly available imaging footprint. The HI clouds, which are drawn from published Galactic Arecibo L-band Feed Array and Arecibo Legacy Fast Arecibo L-band Feed Array HI survey compact cloud catalogs, are selected to be galaxy candidates based on their spatial compactness and non-association with known high-velocity cloud complexes or Galactic HI emission. Based on a comparison of their UV characteristics to those of known dwarf galaxies, half (48%) of the compact HI clouds have at least one potential stellar counterpart with UV properties similar to those of nearby dwarf galaxies. If they are galaxies, then the star formation rates, HI masses, and star formation efficiencies of these systems follow the trends seen for much larger galaxies. The presence of UV emission is an efficient method to identify the best targets for spectroscopic follow-up, which is necessary to prove that the stars are associated with compact HI. Furthermore, searches of this nature help to refine the salient HI properties of likely dwarfs (even beyond the Local Group). In particular, HI compact clouds considered to be velocity outliers relative to their neighbor HI clouds have the most significant detection rate of single, appropriate UV counterparts. Correcting for the sky coverage of the two all-Arecibo sky surveys yielding the compact HI clouds, these results may imply the presence of potentially hundreds of new tiny galaxies across the entire sky.2015ApJ...808..136Dhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/808/136CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/138/338 : Arecibo Legacy Fast ALFA Survey. IX. (Stierwalt+, 2009)J/ApJ/722/395 : Compact H I clouds from the GALFA-H I survey (Begum+, 2010)J/AJ/142/170 : ALFALFA survey: the {alpha}.40 HI source catalogJ/ApJS/192/6 : A GALEX UV imaging survey of nearby galaxies (Lee+, 2011)J/AJ/143/133 : Properties of dwarf galaxies from the ALFALFA surveyJ/ApJ/758/44 : The GALFA-HI compact cloud catalog (Saul+, 2012)J/ApJ/768/77 : Ultra-compact high velocity clouds from ALFALFA (Adams+, 2013)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/808/136https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/808/136http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/808/136https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/808/136https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/808/136http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/808/136GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/808/136/table2 (Single Counterpart Candidates (SCCs))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/808/136/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/808/136/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/808/136/table2?GETtext/xml+votable180.050000true19.798411.12150.005555555555555556Cone search capability for table J/ApJ/808/136/table1 (Summary of HI Clouds)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/808/136/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/808/136/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/808/136/table1?GETtext/xml+votable180.050000true19.804211.11670.0055555555555555566/53 87 207 879 1207 2126 2149 2211 2216 4232 4315 4336 4567 4585 4828 4842 4843 6181 6693 8244 8245 8302 8303 8328 8388 8473 8512 8514 8932 9007 10267 12639 12666 12703 12743 12751 12758 12777 13350 13354 13422 13466 13473 13486 18335 19269 19275 19277 19304 19784 19982 20146 20334 20373 22487 23313 23417 24173 24316 26073 26102 26336 26345 26352 26363 26383 26499 26505 26523 26531 26570 26600 27075 27101 27111 27351 27382 27515 27667 27673 27714 27719 27729 27733 27775 27808 27942 31474 31483 31526 31621 31691 31715 317207.447298006782415e-19 1.4134638842407062e-18https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/808/136?format=asciiRadioUVdefaultJ/ApJ/808/136/table2Single Counterpart Candidates (SCCs)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNumber[1/88] Cloud numbermeta.idintRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainNUVmagGALEX NUV AB magnitudemagphot.mag;em.UVfloate_NUVmagUncertainty in NUVmagmagstat.error;phot.mag;em.UV.200-300nmfloatFUVmagGALEX FUV AB magnitudemagphot.mag;em.UVfloate_FUVmagUncertainty in FUVmagmagstat.error;phot.mag;em.UV.100-200nmfloatMajAxisMajor axis sizearcsecphys.sizefloatMinAxisMinor axis sizearcsecphys.sizefloatb_DistDistance range, lower valueMpcpos.distance;pos.heliocentricfloatB_DistDistance range, upper valueMpcpos.distance;pos.heliocentricfloatb_MHIHI mass range, lower value1e+06solMassphys.massfloatB_MHIHI mass range, upper value1e+06solMassphys.massfloatb_SFRStar Formation Rate range, lower value1e-05solMass.yr**-1phys.SFR;stat.minfloatB_SFRStar Formation Rate range, upper value1e-05solMass.yr**-1phys.SFR;stat.maxfloatSFEStar Formation Efficiency (SFE=SFR/MHI)1e-12yr**-1stat.paramfloatJ/ApJ/808/136/table1Summary of HI CloudsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNumber[1/98] Cloud numbermeta.idintRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainVLSRLocal Standard of Rest velocitykm/sphys.veloc;pos.lsrintVGSRGalactic Standard of Rest velocitykm/sphys.veloc;pos.galacticintVLGSRLocal Group Standard of Rest velocitykm/sphys.velocintSHIIntegrated HI flux densityJy.km/sphot.flux.density;em.line.HI;spect.linefloatSizeSizearcminphys.angSizefloatFWHMFWHM of the HI linekm/sspect.line.width;em.line.HI;spect.linefloatS/NHI signal-to-noise ratiostat.snrfloattNUVNUV exposure timestime.duration;obs.exposure;em.UV.200-300nminttFUVFUV exposure timestime.duration;obs.exposure;em.UV.100-200nmintCatCompact cloud catalog containing detection (1)instr.saturation;meta.tablecharCat-linkLink to the catalog containing detectionmeta.ref.urlintnullableGroup[0/2]? Group of detected UV counterparts (2)meta.codeintnullableSimbadSimbad column added by the CDSmeta.ref.urlchar