J/other/ApSS/365ivo://CDS.VizieR/J/other/ApSS/365.89CDSHuo Z.Dennefeld M.Liu X.Pursimo T.Zhang T.2021-03-29T07:08:31Z2020-08-03T13:54:27ZCDS support team

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

cds-question@unistra.frvariable-starsgalaxiessupernovaequasarsThe ESA-Gaia satellite is regularly producing Alerts on objects where photometric variability has been detected after several passages over the same region of the sky. The physical nature of these objects has often to be determined with the help of complementary observations from ground-based facilities. We have compared the list of Gaia Alerts (from the beginning in 2014 to Nov. 1st, 2018) with archival LAMOST and SDSS spectroscopic data. A search radius of 3" has been adopted. In using survey data, the date of the ground-based observation rarely corresponds to the date of the Alert, but this allows at least the identification of the source if it is persistent, or the host galaxy if the object was only transient like a supernova (SN). Some of the objects have several LAMOST observations, and we complemented this search by adding also SDSS DR15 data in order to look for long-term variability. A list of Gaia Nuclear Transients (GNT) from Kostrzewa-Rutkowska et al. (2018. 2018MNRAS.481..307K, Cat. J/MNRAS/481/307), has been included in this search also. We found 26 Gaia Alerts with spectra in LAMOST+SDSS labelled as stars, among which 12 have multi-epoch spectra. A majority of them are Cataclysmic Variables (CVs). Similarly, 206 Gaia Alerts have associated spectra labelled as galaxies, among which 49 have multi-epoch spectra. Those spectra were generally obtained on a date widely different from the Alert date, and are mostly emission-line galaxies with no particularity (except a few Seyferts), leading to the suspicion that most of the Alerts were due to a SN. As for the GNT list, we found 55 associated spectra labelled as galaxies, among them 13 with multi-epoch spectra. In these two galaxy samples, in only two cases, Gaia17aal and GNTJ170213+2543, was the date of the spectroscopic observation close enough to the Alert date: we find a trace of the SN itself in their LAMOST spectrum, both being now classified here as a type Ia SN. Compared to the galaxy sample from the Gaia alerts, the GNT sample has a higher proportion of AGNs, suggesting that some of the detected variations are also due to the AGN itself. Similarly for Quasars, we found only 30 Gaia Alerts but 68 GNT cases associated with single epoch quasar spectra in the databases. In addition to those, 12 plus 23 are quasars where multi-epoch spectra are available. For ten out of these 35, their multi-epoch spectra show appearance or disappearance of the broad Balmer lines and also variations in the continuum, qualifying them as "Changing Look Quasars" and therefore significantly increasing the available sample of such objects.2020Ap&SS.365...89Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/other/ApSS/365.89CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)V/164 : LAMOST DR5 catalogs (Luo+, 2019)J/MNRAS/481/307 : Gaia Nuclear Transient (GNT) candidateshttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/other/ApSS/365.89https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/other/ApSS/365.89http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/other/ApSS/365.89https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/other/ApSS/365.89https://vizier.iucaa.in/viz-bin/votable?-source=J/other/ApSS/365.89http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/other/ApSS/365.89GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/other/ApSS/365.89/table1 (Spectral information for Gaia alert targets)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/other/ApSS/365.89/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/other/ApSS/365.89/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/other/ApSS/365.89/table1?GETtext/xml+votable180.050000true200.2596145.539430.005555555555555556Cone search capability for table J/other/ApSS/365.89/table2 (Spectral information for GNT targets)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/other/ApSS/365.89/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/other/ApSS/365.89/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/other/ApSS/365.89/table2?GETtext/xml+votable180.050000true0.33945-0.194530.0055555555555555566/755 860 1415 1703 1705 1772 2153 2227 2228 2244 2386 2607 2659 2674 2726 4123 4139 4145 4196 4296 4307 4329 4428 4438 4448 4519 4532 4607 4617 4623 4629 4650 4668 4700 4702 4769 4794 4811 4820 4821 4839 4863 4940 5002 5012 5071 5075 5090 5097 5119 5218 5256 5257 5274 5278 5351 5362 5372 5378 5390 5433 5493 5505 5714 5739 5742 5754 5755 5877 5878 5953 5963 5980 5983 6001 6018 6062 6065 6068 6227 6229 6258 6492 6517 6536 6545 6611 6621 6625 6645 6829 7193 7235 7266 7300 7308 7327 7330 7347 7367 7369 7374 7393 7446 7449 7452 7481 7489 7523 7590 7603 8220 8269 8302 8373 8385 8426 8436 8456 8470 8498 8521 8550 8608 8629 8690 8695 8908 8921 8922 8945 8962 8966 9021 9037 9040 9072 9091 9092 9099 9102 9139 9145 9166 9179 9189 9232 9236 9237 9239 9247 9277 9281 9313 9324 9333 9347 9379 9441 9454 9455 9457 9460 9465 9477 9478 9509 9605 9608 9609 9743 9747 9774 9793 9802 9808 9820 9880 9888 9911 9922 9980 10030 10232 10311 10362 10364 10378 10422 10435 10454 10462 10470 10474 10477 10517 10547 10561 10563 10583 10589 10619 10633 10655 10674 10766 10793 10851 10869 10924 10945 10981 10988 10990 10996 11002 11009 11014 11020 11022 11050 11062 11101 11106 11118 11119 11146 11152 11170 11210 11218 11247 11308 11310 11318 11337 11342 11347 11375 11380 11392 11448 11483 11507 11512 11528 11562 11782 11809 11847 11907 11944 11969 12401 12625 13323 13682 14952 14962 17297 17298 17328 17498 17500 17511 17515 17516 17742 17816 17837 17882 18009 18026 18053 18063 18072 18082 18090 18155 18198 18339 18774 18782 18802 18812 18821 18835 19154 19223 19288 19321 19329 19332 19413 19472 19609 19700 19734 19748 19859 19943 19949 20012 20109 20177 20296 20300 20309 20338 20350 21847 22366 22390 22717 22885 23076 23196 23940 25594 25847 25945 25954 25957 25986 26060 26078 26097 26164 26202 26220 26247 26274 26323 26345 26401 26410 26411 26414 26437 26456 26477 26488 26505 26515 26546 26549 26601 26965 26978 26984 27000 27004 27033 27037 27079 27108 27116 27118 27121 27127 27205 27267 27293 27373 27375 27402 27419 27443 27466 27480 27507 27519 27524 27528 27617 27629 27688 27717 27718 27738 27845 27847 27862 27954 27978 28076 28165 28175 28243 28275 28381 28382 28395 28469 28474 28479 28484 28499 28521 28549 28553 28639 28643 28661 31331 31338 31383 31402 31425 31470 31661 31723 31725 32408 32442 32456 32494 36723 36725 36784 40959 490171.9867573869263685e-19 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/other/ApSS/365.89?format=asciidefaultJ/other/ApSS/365.89/table1Spectral information for Gaia alert targetszRedshift of objectsrc.redshiftcharClassClass of object from spectral archivemeta.code.classcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameObject name in Gaia alerts website, GaiaNNaaameta.id;meta.maincharRA_ICRSRight ascension from Gaia (ICRS) at Ep=2015.5degpos.eq.ra;meta.mainDE_ICRSDeclination from Gaia (ICRS) at Ep=2015.5degpos.eq.dec;meta.mainPreGmag? Mean, historic magnitude of the object, in Gaia's G band before the alertmagphot.mag;em.optfloatnullableGmagGaia G band magnitude of the object at the time of the alertmagphot.mag;em.optfloatAlert.dateDate of observation of the alert, in TCBtime.epochnullableSpec.dateDate of spectral observation, in UTCtime.epochnullableTelTelelscope with associated spectral data of the objectmeta.id;instr.telcharRASdegRight ascension of spectral data (ICRS) at Ep=2015.5magpos.eq.radoubleDESdegDeclination of spectral data (ICRS) at Ep=2015.5magpos.eq.decdoubleSubclassSubclass of object from spectral archivemeta.notecharTypeGalaxy type (G1)src.classcharCommComments about the reason of photometric variabilitymeta.note;src.varchar_RA.icrsRight ascension (ICRS) at Epoch=J2015.5 (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) at Epoch=J2015.5 (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.decnullableindexedJ/other/ApSS/365.89/table2Spectral information for GNT targetsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameObject name in GNT candidates, GNTJHHMMSS.ss+DDMMSS.ss from Kostrzewa-Rutkowska et al., 2018, Cat. J/MNRAS/481/307meta.id;meta.maincharRA_ICRSRight ascension from Gaia (ICRS) at Ep=2015.5degpos.eq.ra;meta.mainDE_ICRSDeclination from Gaia (ICRS) at Ep=2015.5degpos.eq.dec;meta.mainGmagG-band median brightnessmagphot.mag;em.opt.V;stat.mediancharGmagPG-band peak brightnessmagphot.mag;em.opt.V;stat.maxcharAlert.dateDate of the G band peak list in Kostrzewa-Rutkowska et al., 2018, Cat. J/MNRAS/481/307phot.flux.density;em.IR.JnullableSpec.dateDate of spectral observation, in UTCtime.epochnullableTelTelelscope with associated spectral data of the objectmeta.id;instr.telcharRASdeg? Right ascension of spectral data (ICRS) at Ep=2015.5degpos.eq.ranullableDESdeg? Declination of spectral data (ICRS) at Ep=2015.5degpos.eq.decnullablel_z[~] Limit flag on zmeta.code.error;src.redshiftcharzRedshift of objectsrc.redshiftcharClassClass of object from spectral archivemeta.code.classcharSubclassSubclass of object from spectral archivemeta.notecharTypeGalaxy type (G1)src.classcharComComments about the reason of photometric variabilitymeta.note;src.varchar_RA.icrsRight ascension (ICRS) at Epoch=J2015.5 (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.ranullableindexed_DE.icrsDeclination (ICRS) at Epoch=J2015.5 (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.decnullableindexed