J/AJ/162/199ivo://CDS.VizieR/J/AJ/162/199doi:10.26093/cds/vizier.51620199CDSLeahy D.A.Buick M.Postma J.E.2022-05-18T14:06:22Z2022-01-25T12:11:18ZCDS support team

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

cds-question@unistra.frvariable-starsultraviolet-photometryThe Andromeda galaxy (M31) is an object of ongoing study with the Ultraviolet Imaging Telescope (UVIT) on AstroSat. Field 2, which is 6.4kpc in diameter at the distance of M31, includes a substantial part of the NE spiral arms of the galaxy. We have obtained a second observation of Field 2 with the far-ultraviolet (FUV) F148W (148nm) filter, separated from the first observation by 1465 days. Both observations are analyzed to detect sources that are variable at a >3{sigma} confidence level. For sources with less than ~2" separation, we apply multi-Gaussian fits, to obtain reliable magnitudes in the presence of source crowding. The variable sources are found to be concentrated in the spiral arms, with fraction of variable to nonvariable sources ~2 times higher than for interarm regions, indicating an association of FUV variables with young stellar populations. UVIT FUV-NUV color-magnitude diagrams confirm the association of FUV variables with young massive/hot stars. Using existing catalogs, we obtain counterparts for 64 of the 82 most variable sources (>5{sigma}). The counterparts include 13 star clusters, three ionized hydrogen (HII) regions, three novae, one S Doradus star, eight eclipsing binaries, 20 foreground sources, two regular variables, and 14 unspecified variables.2021AJ....162..199Lhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/AJ/162/199CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toB/gcvs : General Catalogue of Variable Stars (Samus+, 2007-2017)I/337 : Gaia DR1 (Gaia Collaboration, 2016)I/345 : Gaia DR2 (Gaia Collaboration, 2018)I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)J/ApJ/759/11 : Wolf-Rayet content of M31 (Neugent+, 2012)J/ApJS/199/37 : GALEX catalog of star clusters in M31 (Kang+, 2012)J/ApJ/786/130 : Catalog of M31 SNR candidates (Lee+, 2014)J/ApJ/802/127 : PHAT stellar cluster survey. II. AP catalog (Johnson+, 2015)J/ApJ/836/64 : Luminous variable stars in M31 & M33. IV. (Humphreys+, 2017)J/AJ/156/241 : First catalog variable stars measured by ATLAS (Heinze+, 2018)J/A+A/630/A92 : The Hubble Catalog of Variables (Bonanos+, 2019)J/ApJS/247/47 : Ultraviolet survey of M31 with UVIT on AstroSat (Leahy+, 2020)J/ApJS/250/23 : AstroSat/UVIT and Chandra X-ray sources in M31 (Leahy+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/AJ/162/199https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/AJ/162/199http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/AJ/162/199https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/AJ/162/199https://vizier.iucaa.in/viz-bin/votable?-source=J/AJ/162/199http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/AJ/162/199GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/AJ/162/199/table2 (Photometry for >3{sigma} variable FUV sources measured in UVIT Field 2)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/AJ/162/199/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/AJ/162/199/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/AJ/162/199/table2?GETtext/xml+votable180.050000true10.9723441.439230.0055555555555555566/2623 2709https://cdsarc.cds.unistra.fr/viz-bin/moc/J/AJ/162/199?format=asciiUVdefaultJ/AJ/162/199/table2Photometry for >3{sigma} variable FUV sources measured in UVIT Field 2recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000[10.7/11.4] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[41.3/41.9] Declination (J2000)degpos.eq.dec;meta.mainF148W-A[16.8/25.6]? Apparent A observation F148W AB magmagphot.mag;em.UVfloatnullablee_F148W-A[0.03/0.6]? Uncertainty in F148W-Amagstat.error;phot.mag;em.UVfloatnullableF148W-C[16.9/32.1]? Apparent C observation F148W AB magmagphot.mag;em.UVfloatnullablee_F148W-C[0.03/6]? Uncertainty in F148W-Cmagstat.error;phot.mag;em.UVfloatnullableF148WSi[3.01/19.2]? Variability {sigma} in F148Wmagphot.mag;em.UVfloatnullableN279N-A[15.4/25.1]? Apparent A observation N279N AB magmagphot.magfloatnullablee_N279N-A[0.03/1]? Uncertainty in N279N-Amagstat.errorfloatnullableN219M-A[16.7/25.7]? Apparent A observation N219M AB magmagphot.magfloatnullablee_N219M-A[0.04/1.1]? Uncertainty in N219N-Amagstat.errorfloatnullableF172M-A[17.8/26.4]? Apparent A observation F172W AB magmagphot.mag;em.UVfloatnullablee_F172M-A[0.05/1.8]? Uncertainty in F172M-Amagstat.error;phot.mag;em.UVfloatnullable