J/A+A/642/L10ivo://CDS.VizieR/J/A+A/642/L10doi:10.26093/cds/vizier.36429010CDSBilek M.Mueller O.Vudragovic A.Taylor R.2021-03-23T14:02:12Z2020-10-08T07:24:44ZCDS support team

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

cds-question@unistra.frgalaxiesphotometryvisible-astronomyThe blind HI survey Arecibo Galaxy Environment Survey (AGES) detected several unresolved sources in the Virgo cluster, which do not have optical counterparts in the Sloan Digital Sky Survey. The origin of these dark clouds is unknown. They might be crucial objects since they could be the so-called dark galaxies, that is, the dark matter halos without stellar content that are expected from cosmological simulations. In order to reveal the nature of the dark clouds, we took a deep optical image of one them, AGESVC1 282, with the newly-commissioned 1.4m Milankovic Telescope. After observing it for 10.4h in the L-filter, the image reached a surface-brightness limit of about 29.1mag/arcsec^+2^ in V. No optical counterpart was detected. We placed an upper limit on the Vband luminosity of the object of 1.1x10^7^L_{sun}_, giving a stellar mass below 1.4x10^7^M_{sun}_ and a HI-to-stellar mass ratio above 3.1. By inspecting archival HI observations of the surrounding region, we found that none of the standard explanations for optically dark HI clouds fits the available constraints on this object.2020A&A...642L..10Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/642/L10CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/MNRAS/423/787 : AGES sources in Virgo cluster (Taylor+, 2012)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/642/L10https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/642/L10http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/642/L10https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/642/L10https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/642/L10http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/642/L10GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/642/L10/list (Information on fits image)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/642/L10/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/642/L10/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/642/L10/list?GETtext/xml+votable180.050000true186.348898.271220.0055555555555555566/27725https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/642/L10?format=asciiOpticaldefaultJ/A+A/642/L10/listInformation on fits imagerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right Ascension of center (J2000)degpos.eq.ra;meta.mainDEJ2000Declination of center (J2000)degpos.eq.dec;meta.mainscaleScale of the imagearcsec/pixinstr.scalefloatNxNumber of pixels along X-axismeta.numberintNyNumber of pixels along Y-axismeta.numberintsizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitschar