J/ApJS/244/29ivo://CDS.VizieR/J/ApJS/244/29doi:10.26093/cds/vizier.22440029CDSMroz P.Udalski A.Skowron J.Szymanski M.K.Soszynski I.,Wyrzykowski L.Pietrukowicz P.Kozlowski S.Poleski R.Ulaczyk K.,Rybicki K.Iwanek P.2021-09-10T14:03:18Z2020-04-14T12:24:10ZCDS support team

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

cds-question@unistra.frgravitational-lensingmilky-way-galaxyinfrared-photometryvisible-astronomyphotometryThe number and properties of observed gravitational microlensing events depend on the distribution and kinematics of stars and other compact objects along the line of sight. In particular, precise measurements of the microlensing optical depth and event rate toward the Galactic bulge enable strict tests of competing models of the Milky Way. Previous estimates, based on samples of up to a few hundred events, gave larger values than expected from the Galactic models and were difficult to reconcile with other constraints on the Galactic structure. Here we used long-term photometric observations of the Galactic bulge by the Optical Gravitational Lensing Experiment (OGLE) to select a homogeneous sample of 8000 gravitational microlensing events. We created the largest and most accurate microlensing optical depth and event rate maps of the Galactic bulge. The new maps ease the tension between the previous measurements and Galactic models. They are consistent with some earlier calculations based on bright stars and are systematically ~30% smaller than the other estimates based on "all-source" samples of microlensing events. The difference is caused by the careful estimation of the source star population. The new maps agree well with predictions based on the Besancon model of the Galaxy. Apart from testing the Milky Way models, our maps may have numerous other applications, such as the measurement of the initial mass function or constraining the dark matter content in the Milky Way center. The new maps will also inform the planning of future space-based microlensing experiments by revising the expected number of events.2019ApJS..244...29Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJS/244/29CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/AcA/50/1 : OGLE microlensing events in Galactic Bulge (Udalski+, 2000)J/AcA/50/421 : OGLE-II DIA BUL_SC1 field (Wozniak, 2000)J/AcA/51/175 : OGLE-II DIA microlensing events (Wozniak+, 2001)J/AcA/52/217 : OGLE II. VI photometry of Galactic Bulge (Udalski+, 2002)J/A+A/454/185 : EROS-2 microlensing parameters (Hamadache+, 2006)J/A+A/466/157 : Bulge Microlensing Events (Soto+, 2007)J/A+A/453/635 : Modelling the Gal. Interstellar Extinction (Marshall+, 2006)J/ApJ/636/240 : OGLE II microlensing parameters (Sumi+, 2006)J/ApJ/711/L48 : 2008 OGLE Bulge microlensing alerts (Cohen+, 2010)J/A+A/529/A102 : MOA-2007-BLG-387Lb light curve I band (Batista+, 2011)J/ApJ/778/150 : Microlensing events toward the Bulge from MOA-II (Sumi+, 2013)J/ApJS/216/12 : OGLE-III Gal. bulge microlensing events (Wyrzykowski+, 2015)J/ApJ/827/139 : Microlensing optical depths from MOA-II (Sumi+, 2016)J/MNRAS/458/3012 : OGLE-III Parallax microlensing events (Wyrzykowski+, 2016)J/AJ/154/210 : 2015 high-cadence Spitzer microlensing events (Zhu+, 2017)J/A+A/605/A89 : Abundances of microlensed Bulge stars. VI. (Bensby+, 2017)J/A+A/616/A12 : Gaia DR2 sources in GC and dSph (Gaia Collaboration+, 2018)J/AJ/155/186 : The KMTNet/K2-C9 (Kepler) Data Release (Kim+, 2018)http://ogle.astrouw.edu.pl/cgi-ogle/get_o4_tau.py : Web interface associatedhttp://www.astrouw.edu.pl/ogle/ogle4/microlensing_maps/ : Associated datahttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJS/244/29https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJS/244/29http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJS/244/29https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJS/244/29https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJS/244/29http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJS/244/29GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/ApJS/244/29/table3 (Best-fitting parameters of the analyzed microlensing events in low-cadence OGLE fields)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/244/29/table3?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/244/29/table3?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/244/29/table3?GETtext/xml+votable180.050000true258.2833333-29.80361110.005555555555555556Cone search capability for table J/ApJS/244/29/table5 (Surface density of stars in OGLE-IV subfields calculated using image-level simulations)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/244/29/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/244/29/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/244/29/table5?GETtext/xml+votable180.050000true268.526-29.0810.005555555555555556Cone search capability for table J/ApJS/244/29/fields (Basic information and microlensing optical depth and event rates in the OGLE-IV fields (averaged over sources brighter than I=21) (Tables 6 and 7))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/ApJS/244/29/fields?https://vizier.iucaa.in/viz-bin/conesearch/J/ApJS/244/29/fields?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/ApJS/244/29/fields?GETtext/xml+votable180.050000true267.9992-28.60970.0055555555555555564/1794 1795 1798 1801 1803 1804 1805 1806 5/7174 7175 7198 7200 7201 7203 7209 7211 7230 7243 7296 7300 7301 7312 7313 7316 10591 11967 12008 12009 12010 6/28683 28685 28686 28687 28744 28746 28747 28750 28751 28756 28757 28784 28786 28787 28796 28798 28799 28808 28810 28811 28832 28833 28835 28841 28842 28843 28912 28914 28915 28916 28917 28924 28926 28928 28966 28967 29056 29058 29059 29064 29065 29066 29188 29256 29257 29259 29260 29261 29268 29270 29272 29273 29275 42357 42359 42449 42452 42453 42455 42461 42495 42837 48014 48015 480442.367228618189496e-19 2.6706780932288093e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/ApJS/244/29?format=asciiOpticalInfrareddefaultJ/ApJS/244/29/table3Best-fitting parameters of the analyzed microlensing events in low-cadence OGLE fieldsEWSOGLE EWS ID(s)meta.idcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameStar namemeta.id;meta.maincharFieldOGLE-IV field nameobs.fieldcharsFieldOGLE-IV subfield name within Fieldobs.fieldintStar[50/208567] Star ID in the OGLE-IV databasemeta.idintRAJ2000[17/18] Hour of Right Ascension (J2000)pos.eq.ra;meta.mainDEJ2000[19/38] Degree of Declination (J2000)pos.eq.dec;meta.mainGLON[-8.6/9.9] Galactic longitudedegpos.galactic.lonGLAT[-14.9/6.3] Galactic latitudedegpos.galactic.latdoublet0-bestBest-fit t0, time of closest approach, Heliocentric Julian Datedtime.epoch;pos.heliocentric;meta.modelleddoubletE-best[1.58/303] Best-fit tE, Einstein timescaledtime.scalefloatu0-best[0/1] Best-fit u0, projected separationsrc.impactParamfloatIs-best[13.9/21] Best-fit I-band source magnitudemagphot.mag;em.opt.Ifloatfs-best[0.01/3.8] Best-fit blending parameter (1)phys.luminosity;arith.ratiofloatt0-medMedian t0, time of closest approach, Heliocentric Julian Datedtime.epoch;stat.mediandoublee_t0-med[-37.2/0] Negative error bar, t0-meddstat.errorfloatE_t0-med[0/43] Positive error bar, t0-meddstat.error;stat.maxfloattE-med[1.7/8812] Median tE, Einstein timescaledtime.scaledoublee_tE-med[-4821/-0.04] Negative error bar, tE-meddstat.errordoubleE_tE-med[0.06/19953] Positive error bar, tE-meddstat.error;stat.maxdoubleu0-med[0/1.3] Median u0, projected separationsrc.impactParamfloate_u0-med[-0.8/0] Negative error bar, u0-medstat.errorfloatE_u0-med[0/1.5] Positive error bar, u0-medstat.error;stat.maxfloatIs-med[13.9/26.5] Median I-band source magnitudemagphot.mag;em.opt.Ifloate_Is-med[-6.8/-0.005] Negative error bar, Is-medmagstat.errorfloatE_Is-med[0.006/5.2] Positive error bar, Is-medmagstat.error;stat.maxfloatfs-med[0/3.5] Median blending parameter (1)phys.luminosity;arith.ratiofloate_fs-med[-0.6/0] Negative error bar, fs-medstat.errorfloatE_fs-med[0/0.9] Positive error bar, fs-medstat.error;stat.maxfloatWeight[2/129.2] Inverse of the detection efficiencystat.weightfloatFileDownload the I-band photometry; ASCII filemeta.ref.urlcharLCInteractive plotmeta.ref.urlcharSimbadSimbad column added by the CDSmeta.ref.urlcharJ/ApJS/244/29/table5Surface density of stars in OGLE-IV subfields calculated using image-level simulationsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFieldOGLE-IV field nameobs.fieldcharsFieldOGLE-IV subfield name within Fieldobs.fieldintRAJ2000[258.28/286.67] Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-38.4/-19.2] Declination (J2000)degpos.eq.dec;meta.mainGLON[-8.6/10.6] Galactic longitudedegpos.galactic.lonGLAT[-16.5/6.4] Galactic latitudedegpos.galactic.latfloatsigma18[3.7/369.7] Star surface density in the range 14<I<18arcmin**-2src.densityfloatsigma21[42.8/4609.2] Star surface density in the range 14<I<21arcmin**-2src.densityfloatN18[603/60940] Number of stars in the range 14<I<18meta.numberintN21[7183/756286] Number of stars in the range 14<I<21meta.numberintNsNumber of microlensing event for this subfield (link to Table 3)meta.numberintnullableJ/ApJS/244/29/fieldsBasic information and microlensing optical depth and event rates in the OGLE-IV fields (averaged over sources brighter than I=21) (Tables 6 and 7)GLAT[-16/6] Galactic latitudedegpos.galactic.latdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFieldOGLE-IV field namemeta.id;meta.maincharprimaryRAJ2000[259/286] Right ascension (J2000)degpos.eq.ra;meta.mainDEJ2000[-38/-19.7] Declination (J2000)degpos.eq.dec;meta.mainGLON[-8/10] Galactic longitudedegpos.galactic.lonNs[0.5/7.1] Number of monitored starsmeta.numberfloatNep[36/12099] Number of epochsmeta.numberintNfNumber of subfields for this field (link to Table 5)meta.numberintnullabletau[0/3.7] Optical depth {tau}_300_phys.absorption.opticalDepthfloate_tau[0/1.3] Uncertainty of taustat.errorfloatGam[0/26.5] Event rate {Gamma} per star per 10^6^ year1e-06yr**-1time;arith.ratiofloate_Gam[0/7.1] Uncertainty of gam1e-06yr**-1stat.errorfloatGam.d[0/265.3] Event rate {Gamma}_deg2_ per unit area (in square degree) per yeardeg**-2.yr**-1time;arith.ratiofloate_Gam.d[0/16.3] Uncertainty of gam-deg2deg**-2.yr**-1stat.errorfloattE-mean[0/79.6] Mean Einstein timescale <t_E_>dtime.scalefloate_tE-mean[0/79.6] Uncertainty of tE-meandstat.errorfloatNev[0/441] Number of detected eventsmeta.numberintN21[0.4/19.1] Number of sources brighter than I=21meta.numberfloatFileDownload the event detection efficiencies for this field; ASCII filemeta.ref.urlcharEffInteractive plotmeta.ref.urlchar