J/A+A/640/A83ivo://CDS.VizieR/J/A+A/640/A83doi:10.26093/cds/vizier.36400083CDSKlueter J.Bastian U.Wambsganss J.2021-12-15T08:30:09Z2020-08-17T08:39:20ZCDS support team

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

cds-question@unistra.frastrometrystellar-massesAstrometric gravitational microlensing can be used to determine the mass of a single star (the lens) with an accuracy of a few percent. To do so, precise measurements of the angular separations between lens and background star with an accuracy below 1 milli-arcsecond at different epochs are needed. Therefore only the most accurate instruments can be used. However, since the timescale is on the order of months to years, the astrometric deflection might be detected by Gaia, even though each star is only observed on a low cadence. We want to show how accurately Gaia can determine the mass of the lensing star. Using conservative assumptions based on the results of the second Gaia data release (GaiaDR2), we simulated the individual Gaia measurements for 501 predicted astrometric microlensing events during the Gaia era (2014.5 - 2026.5). For this purpose we used the astrometric parameters of Gaia DR2, as well as an approximative mass based on the absolute G magnitude. By fitting the motion of the lens and source simultaneously, we then reconstructed the 11 parameters of the lensing event. For lenses passing by multiple background sources, we also fitted the motion of all background sources and the lens simultaneously. Using a Monte-Carlo simulation we determined the achievable precision of the mass determination. We find that Gaia can detect the astrometric deflection for 114 events. Furthermore, for 13 events Gaia can determine the mass of the lens with a precision better than 15% and for 13 + 21 = 34 events with a precision of 30% or better.2020A&A...640A..83Khttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/640/A83CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration, 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/640/A83https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/640/A83http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/640/A83https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/640/A83https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/640/A83http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/640/A83GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/640/A83/table (Determined precision for each event)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/640/A83/table?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/640/A83/table?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/640/A83/table?GETtext/xml+votable180.050000true54.995083363.87041670.0055555555555555566/3050 3313 3345 3403 3468 3791 3883 4038 4250 4652 4895 5895 6836 7217 8075 8222 8891 10262 10964 11142 11546 12917 13301 13934 13945 14056 14789 16455 16758 16984 17714 18802 19830 20398 20873 22754 24147 25396 26081 26742 27299 27954 29251-29252 29833 30041 30505 30989 31630 31781 32089 32224 32854 33096 33306 33964 34062 35315 36480 37132 37201 37257 37332 37677 37725 37744 37890 37904 37942 37949 38322 38347 38581 39027 39326 39792 40477 40760 41127 41225 41562 41591 41612 41675 42074 42139 42216 42220 42485 42856 43547 44124 44151 44437 45249 45585 46539 46790 47442 48230 48843https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/640/A83?format=asciidefaultJ/A+A/640/A83/tableDetermined precision for each eventSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameCommon Name of the Lensmeta.id;meta.maincharLensIDGaia DR2 Source_id of the lensmeta.idSourceIDGaia DR2 Source_id of the sourcemeta.idfivepar[0/1] Does Gaia DR2 provides a five - parameter solution of the source?meta.codeintTCADate of the closest approachyrtime.epochdoubleMassApproximated mass of the LenssolMassphys.massdoubledeltaM10Determined standard error for the mass determination for the extended 10-years mission (deltaM_10)solMassstat.errordoubleE_deltaM10upper uncertainty of the standard error for the extended mission (sigma_deltaM_10_+)solMassstat.error;stat.maxdoublee_deltaM10[] lower uncertainty of the standard error for the extended mission (sigma_deltaM_10_-)solMassstat.errordoubledeltaM5Determined standard error for the mass determination for the nominal 5-years mission (deltaM_5)solMassstat.errordoubleE_deltaM5upper uncertainty of the standard error for the nominal mission (sigma_deltaM_5_+)solMassstat.error;stat.maxdoublee_deltaM5[] lower uncertainty of the standard error for the nominal mission (sigma_deltaM_5_-)solMassstat.errordoubledeltaMext? Determined standard error for the mass determination for the extended 10-year mission including external observations (deltaM_ext)solMassstat.errordoublenullableE_deltaMext? upper uncertainty of the standard error for the nominal mission plus external observations (sigma_deltaM_ext_+)solMassstat.error;stat.maxdoublenullablee_deltaMext[]? lower uncertainty of the standard error for the nominal mission plus external observations (sigma_deltaM_ext_-)solMassstat.errordoublenullable_RAPositions from Simbad and Gaia DR2 (right ascension part)degpos.eq.ra;meta.main_DEPositions from Simbad and Gaia DR2 (declination part)degpos.eq.dec;meta.main