J/ApJ/892/112ivo://CDS.VizieR/J/ApJ/892/112doi:10.26093/cds/vizier.18920112CDSSoraisam M.D.Saha A.Matheson T.Lee C.-H.Narayan G.Vivas A.K.,Scheidegger C.Oppermann N.Olszewski E.W.Sinha S.Desantis S.R.,(The ANTARES Collaboration)2022-09-06T12:22:20Z2021-09-15T09:59:49ZCDS support team

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

cds-question@unistra.frvariable-starsgalaxy-planesmilky-way-galaxyinfrared-photometryvisible-astronomybroad-band-photometrysurveysWith the advent of the Legacy Survey of Space and Time, time-domain astronomy will be faced with an unprecedented volume and rate of data. Real-time processing of variables and transients detected by such large-scale surveys is critical to identifying the more unusual events and allocating scarce follow-up resources efficiently. We develop an algorithm to identify these novel events within a given population of variable sources. We determine the distributions of magnitude changes (dm) over time intervals (dt) for a given passband f, p_f_^(dm|dt)^, and use these distributions to compute the likelihood of a test source being consistent with the population or being an outlier. We demonstrate our algorithm by applying it to the DECam multiband time-series data of more than 2000 variable stars identified by Saha+ (2019, J/ApJ/874/30) in the Galactic Bulge that are largely dominated by long-period variables and pulsating stars. Our algorithm discovers 18 outlier sources in the sample, including a microlensing event, a dwarf nova, and two chromospherically active RS CVn stars, as well as sources in the blue horizontal branch region of the color-magnitude diagram without any known counterparts. We compare the performance of our algorithm for novelty detection with the multivariate Kernel Density Estimator and Isolation Forest on the simulated PLAsTiCC data set. We find that our algorithm yields comparable results despite its simplicity. Our method provides an efficient way for flagging the most unusual events in a real-time alert-broker system.2020ApJ...892..112Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/892/112CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toII/213 : OGLE Galactic Bulge periodic variables (Udalski+ 1996)J/AcA/52/129 : DIA OGLE2 candidate variable stars catalog (Wozniak+, 2002)J/MNRAS/364/117 : OGLE2 Mira variables in the Galactic bulge (Matsunaga+, 2005)J/AJ/131/1044 : Chromospherically active stars in the Bulge (Drake, 2006)J/AcA/61/1 : VI light curves of Galactic Bulge RR Lyrae (Soszynski+, 2011)J/ApJS/194/4 : Classification of CCCP X-ray sources (Broos+, 2011)J/AcA/61/285 : VI light curves of Galactic Bulge Cepheids (Soszynski+, 2011)J/ApJ/778/150 : Microlensing events toward the Bulge from MOA-II (Sumi+, 2013)J/A+A/572/A29 : Asteroids for a targeted spectrosc. survey (Oszkiewicz+, 2014)J/AcA/65/313 : One thousand new dwarf novae from the OGLE Survey (Mroz+, 2015)J/AcA/66/405 : Galactic bulge eclipsing & ellipsoidal bin. (Soszynski+, 2016)J/A+A/605/A89 : Abund. of microlensed Bulge dwarf stars. VI. (Bensby+, 2017)J/ApJ/874/30 : RRab toward Baade's window with Blanco/DECam (Saha+, 2019)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/892/112https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/892/112http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/892/112https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/892/112https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/892/112http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/892/112GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJ/892/112/stars (List of variable stars; table added by CDS)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/892/112/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/892/112/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/892/112/stars?GETtext/xml+votable180.050000true270.67905-29.905540.005555555555555556Cone search capability for table J/ApJ/892/112/table1 (Light curve data)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJ/892/112/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJ/892/112/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJ/892/112/table1?GETtext/xml+votable180.050000true270.67905-29.905540.0055555555555555565/7194 6/28733 28735 28821 28864-28865https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJ/892/112?format=asciiOpticalInfrareddefaultJ/ApJ/892/112/starsList of variable stars; table added by CDSS19Display data from Saha+, 2019, J/ApJ/874/30meta.ref.urlintnullableNpNumber of photometry measurements for this star (link to Table 1)meta.numberintnullableLCInteractive LC Plotmeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar name (B1-NNNNNNN)meta.id;meta.maincharprimaryRAJ2000[269.65/272.13] Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-31/-29] Declination (J2000)degpos.eq.dec;meta.mainJ/ApJ/892/112/table1Light curve datarecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharRAJ2000Right Ascension in decimal degrees (J2000)degpos.eq.ra;meta.mainindexedDEJ2000Declination in decimal degrees (J2000)degpos.eq.dec;meta.mainindexedHJD[56423.65/57116.91] Heliocentric Julian Date, HJD-2400000.0dtime.epochdoubleindexedBandPassband used (u, g, r, i or z)instr.setupcharmag[9.85/21.5] Observed magnitude in Bandmagphot.magfloate_mag[0.01/0.85] Uncertainty in magmagstat.error;phot.magfloat