J/MNRAS/540/2685ivo://CDS.VizieR/J/MNRAS/540/2685doi:10.26093/cds/vizier.75402685CDSEgbo O.D.Buckley D.A.H.Groot P.J.Cavallaro F.Woudt P.A.,Thompson M.A.Mutale M.Bietenholz M.2025-10-10T20:12:18Z2025-06-19T09:07:27ZCDS support team

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

cds-question@unistra.frgalaxy-planesmilky-way-galaxyradio-astronomyvisible-astronomyastronomical-object-identificationWe report on optically selected stellar candidates of SARAO MeerKAT 1.3 GHz radio continuum survey sources of the Galactic plane. Stellar counterparts to radio sources are selected by cross-matching the MeerKAT source positions with Gaia DR3, using two approaches. The first approach evaluated the probability of chance alignments between the radio survey and Gaia sources and used AllWISE infrared colour-colour information to select potential stellar candidates. The second approach utilized a Monte Carlo method to evaluate the cross-matching reliability probability, based on populations of known radio-emitting stars. From the combined approaches, we found 629 potential stellar counterparts, of which 169 have existing SIMBAD classifications, making it the largest Galactic plane radio-optical crossmatch sample to date. A colour-magnitude analysis of the sample revealed a diverse population of stellar objects, ranging from massive OB stars, main-sequence stars, giants, young stellar objects, emission line stars, red dwarfs and white dwarfs. Some of the proposed optical counterparts include chromospherically/coronally active stars, for example RS CVn binaries, BY Dra systems, YSOs and flare stars, which typically exhibit radio emission. Based on Gaia's low-resolution spectroscopy, some of the stars show strong H{alpha} emission, indicating they are magnetically active, consistent with them being radio emitters. While MeerKAT's sensitivity and survey speed make it ideal for detecting faint radio sources, its angular resolution limits accurate counterpart identification for crowded fields such as the Galactic Plane. Higher frequency, and, thereby, better spatial resolution, radio observations plus circular polarization would be required to strengthen the associations.2025MNRAS.540.2685Ehttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/540/2685CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/540/2685https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/540/2685http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/540/2685https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/540/2685https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/540/2685http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/540/2685GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/540/2685/catalog (Cross-matched MeerKAT SMGPS-Gaia catalog)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/540/2685/catalog?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/540/2685/catalog?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/540/2685/catalog?GETtext/xml+votable180.050000true266.6741664046896-26.99186328173930.0055555555555555565/3242 7672 9437-9438 9470 9473 9475-9476 9811 9817 9819-9820 9822 9841 9843 10414 10442 10608 10753 6/12972 12974 12984 12986-12987 12990 14336-14337 14339-14341 14343 14354-14356 14358 14361 28801-28803 28806 28808-28810 28812 28815 28824 28853 28874-28876 28879 28896-28897 28900-28901 28913-28914 28916 28921 28924-28925 29089-29090 29094-29097 29112 29116-29117 29162 29445 29457 29459 29461 29504-29505 29507-29508 29516 29520 29522 29530 30216 30218 30220 30222-30223 30256 30264 30271 30306 30313 30315 30318 30331 30334 30401 30416 30419 30422 30596 30599 30605-30607 30616-30617 30623 30628 30640 30643-30644 30666 30692 30700-30701 30707 30710 30713 30715-30716 30718-30719 32084 37246 37333 37340 37365 37367 37369-37370 37372-37373 37375 37713 37715-37716 37718-37721 37723-37725 37727 37743-37746 37756-37758 37840 37842-37846 37848-37850 37861 37863 37869 37871 37874-37876 37884 37891 37897-37898 37908 37912-37913 37922 37925-37926 37928 37931-37934 38016 38022 38024-38026 38048-38049 38051 38056 38058 39236-39238 39249 39251 39257-39259 39376 39378-39379 39384-39385 39396 39399 39405 39408 39410 41597-41598 41647 41649-41654 41660 41662 41669 41671 41673-41674 41678-41682 41686-41688 41700 41704 41762 41764-41766 41774 41776-41777 41781 41784 41798-41799 41801-41805 41807 41816 41826 41856-41857 42154-42156 42159 42166 42168-42169 42174-42175 42202 42209 42214 42217 42229 42377-42379 42382-42383 42393-42395 42397-42399 42401 42404-42405 42438-42440 42443 42446 42454 42496 42504 42512 43016-43017 43019-43022 43024 43026 43028 43040 430441.987820871092403e-24 3.916500758235022e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/540/2685?format=asciiOpticalRadiodefaultJ/MNRAS/540/2685/catalogCross-matched MeerKAT SMGPS-Gaia catalogSMGPSSMGPS identifier (GLLL/ll+B.bbbb)meta.id;meta.maincharRA1degGaia right ascension (ICRS) at Ep=J2019.4degpos.eq.raDE1degGaia declination (ICRS) at Ep=J2019.4degpos.eq.decdRA1degCorrection for right ascension (ICRS) at Ep=J2019.4maspos.eq.ra;arith.diffdoubledDE1degCorrection declination (ICRS) at Ep=J2019.4maspos.eq.dec;arith.diffdoublerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintFileNameSMGPS image file namemeta.id;meta.filecharGLONGalactic Longitudedegpos.galactic.lone_GLONSource-finding fitting error on longitudedegstat.errordoubleGLATGalactic Latitudedegpos.galactic.latdoublee_GLATSource-finding fitting error on latitudedegstat.errordoubleFpeakMeerKAT 1.3.GHz peak flux density (1)mJy/beamphot.flux.density;em.radio.750-1500MHzdoublee_FpeakError on MeerKAT 1.3.GHz peak flux densitymJy/beamstat.errordoubleFintMeerKAT 1.3.GHz integrated flux density (1)mJyphot.flux.density;em.radio.750-1500MHzdoublee_FintError on MeerKAT 1.3.GHz integrated flux densitymJystat.errordoubleaFitted semi-major axisarcsecphys.angSize;srcdoublee_a? Error on semi-major axisarcsecstat.errordoublenullablebFitted semi-minor axisarcsecphys.angSize.sminAxis;meta.modelleddoublee_b? Error on semi-minor axisarcsecstat.errordoublenullableRA_ICRSSMGPS right ascension (ICRS) at Ep=2019.4degpos.eq.ra;meta.mainDE_ICRSSMGPS declination (ICRS) at Ep=2019.4degpos.eq.dec;meta.maine_RA_ICRSError in right ascensionarcsecstat.error;pos.eq.radoublee_DE_ICRSError in declinationarcsecstat.error;pos.eq.decdoubleePosCombined RA and Dec errorarcsecstat.errordoubleGaiaDR3The Gaia DR3 source identifiermeta.idRAGdegGaia right ascension (ICRS) at Ep=2016.0degpos.eq.raDEGdegGaia Declinayion (ICRS) at Ep=2016.0degpos.eq.dece_RAGdegError in RAGdegmasstat.errorfloate_DEGdegError in DEGdegmasstat.errorfloatSolIDGaia DR3 solution identifiermeta.id;stat.fitPlxGaia DR3 parallaxmaspos.parallaxfloatPMGaia DR3 total proper motionmas/yrpos.pmfloatGmagGaia G-band mean magnitudemagphot.mag;em.optdoubleBPmagGaia BP-band mean magnitudemagphot.mag;em.opt.BdoubleRPmagGaia RP-band mean magnitudemagphot.mag;em.opt.RdoubleRA2degRight ascension (J2000)degpos.eq.raDE2degDeclination (J2000)degpos.eq.dece_RA2degError in RA2degmasstat.error;pos.eq.radoublee_DE2degError in DE2degmasstat.error;pos.eq.decdoubleTIC? TESS Input Catalog identifiermeta.idnullableAllWISEAllWISE identifier (JHHMMSS.ss+DDMMSS.s)meta.idchar2MASS2MASS identifier (HHMMSSss+DDMMSss)meta.idcharrpgeoPhotogeometric distancepcpos.distancedoublefo1sig? Normalised positional offset (1{sigma})pos;arith.diffdoublenullableso1sig? Match confidence level (1{sigma})stat.fit.goodnessdoublenullableE(B-V)Extinction value E(B-V)magphot.color.excessfloatG0magDereddened G-band magnitudemagphot.mag;em.optdoubleGMAGG-band absolute magnitudemagphys.magAbsdoubleFoptOptical flux derived from G0magmJyphot.flux.density;em.optdoubleGmagabG-band AB magnitudemagphot.mag;em.optdoubleLumOptOptical luminosity1e-07Wphys.luminosity;em.optdoubleLumRadRadio luminosity1e-07W.Hz**-1phys.luminosity;em.radiodoubleSepSGSMGPS-Gaia angular separationarcsecpos.angDistancedouble