J/ApJS/173/673ivo://CDS.VizieR/J/ApJS/173/673doi:10.26093/cds/vizier.21730673CDSWelsh B.Y.Wheatley J.M.Seibert M.Browne S.E.West A.A.,Siegmund O.H.W.Barlow T.A.Forster K.Friedman P.G.Martin D.C.,Morrissey P.Small T.Wyder T.Schiminovich D.Neff S.Rich R.M.2017-10-16T14:58:35Z2009-07-07T21:58:49ZCDS support team

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

cds-question@unistra.frvariable-starsapparent-magnitudeultraviolet-astronomyWe present the preliminary results from implementing a new software tool that enables inspection of time-tagged photon data for the astronomical sources contained within individual GALEX ultraviolet (UV) images of the sky. We have inspected the photon data contained within 1802 GALEX images to reveal rapid, short-term (<~500s) UV source variability in the form of stellar "flares." The mean associated change in near-UV (NUV) magnitude due to this flaring activity is 2.7+/-0.3mag. A list of 49 new UV variable star candidates is presented (associated with 52 separate flare events), together with their associated Sloan Digital Sky Survey (SDSS) photometric magnitudes. From these data we can associate the main source of these UV flare events with magnetic activity on M dwarf stars. Photometric parallaxes have been determined for 32 of these sources, placing them at distances ranging from approximately 25 to 1000pc. The average UV flare energy for these flare events is 2.5x10^30^ergs, which is of a similar energy to that of U-band, X-ray, and EUV flares observed on many local M dwarf stars. We have found that stars of classes M0 to M5 flare with energies spanning a far larger range and with an energy approximately 5 times greater than those of later (M6 to M8) spectral type.2007ApJS..173..673Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/173/673CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AJ/130/825 : GALEX ultraviolet variability catalog (Welsh+, 2005)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/173/673https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/173/673http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/173/673https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/173/673https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/173/673http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/173/673GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/173/673/table1 (List of short-term UV variable objects)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/173/673/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/173/673/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/173/673/table1?GETtext/xml+votable180.050000true39.9813333-7.48205560.0055555555555555566/5352 7185 7229 7363 7451 7467 7474 7521 8224 8227 9117 9343 9428 10145 10183 10191 10212 11230 11252 11425 11924 18538 18544 18616 18793 18839 18849 19109 19687 20002 23055 25599 25848 26067 26972 27256 27257 27258 27298 27767 30029 30041 367902.040811542443644e-19 4.653515163505597e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/173/673?format=asciiUVdefaultJ/ApJS/173/673/table1List of short-term UV variable objectsFieldGALEX Field (MAST Identifier)meta.id;obs.fieldcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintn_SDSSSimbad column added by the CDSmeta.ref.urlcharSDSSSDSS-DR4 ID (JHHMMSS.ss+DDMMSS.s) (1)meta.id;meta.maincharprimaryNobsNumber of observationsmeta.numberintNUVmNUV (175-275nm) magnitude maximummagphot.mag;em.UVfloatNUVvNUV (175-275nm) magnitude variationmagsrc.var.amplitudefloatgmag? SDSS g band magnitudemagphot.mag;em.opt.Bfloatnullablef_gmag[b] magnitude uncertain due to CCD saturationmeta.codecharrmag? SDSS r band magnitudemagphot.mag;em.opt.Rfloatnullablef_rmag[b] magnitude uncertain due to CCD saturationmeta.codecharimag? SDSS i band magnitudemagphot.mag;em.opt.Ifloatnullablef_imag[b] magnitude uncertain due to CCD saturationmeta.codecharzmag? SDSS z band magnitudemagphot.mag;em.opt.Ifloatnullablef_zmag[b] magnitude uncertain due to CCD saturationmeta.codecharNotesProbable spectral Type (or Simbad identifier)meta.notecharf_Notes[c] Spectral type based on USNOB datameta.notecharSDSS-DR6Exact name from SDSS-DR6 (column added at CDS)meta.idchar_RAposition from SDSS-DR6 (Cat. II/282) (right ascension part)degpos.eq.ra;meta.mainnullable_DEposition from SDSS-DR6 (Cat. II/282) (declination part)degpos.eq.dec;meta.mainnullableJ/ApJS/173/673/table2M dwarf distances, NUV luminosities and flare energiesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSDSSSDSS-DR4 Identifiermeta.id;meta.maincharSpTypeSpectral Typesrc.spTypecharDistHeliocentric distancepcpos.distanceintLbolLog of bolometric luminositylog(solLum)phys.luminosityfloatENUVTotal NUV flare energy1e-07Jphys.luminosity;em.UVdoublen_ENUV[a] Note when two flares observedmeta.notecharLfl/Lbollog of NUV flare luminosity referenced to the stellar bolometric luminosityphys.luminosity;arith.ratiofloat