J/A+A/645/A115ivo://CDS.VizieR/J/A+A/645/A115doi:10.26093/cds/vizier.36450115CDSWang S.Chen B.Ma J.2021-09-10T09:11:52Z2021-01-22T09:46:17ZCDS support team

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

cds-question@unistra.frgalaxy-clustersmetallicityphotometryvisible-astronomyDetermining the metallicities and ages of M31 clusters is fundamental to the study of the formation and evolution of M31 itself. The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) has carried out a systematic spectroscopic campaign of clusters and candidates in M31. We constructed a catalogue of 346 M31 clusters observed by LAMOST. By combining the information of the LAMOST spectra and the multi-band photometry, we developed a new algorithm to estimate the metallicities and ages of these clusters. We distinguish young clusters from old using random forest classifiers based on a empirical training data set selected from the literature. Ages of young clusters are derived from the spectral energy distribution fits of their multi-band photometric measurements. Their metallicities are estimated by fitting their observed spectral principal components extracted from the LAMOST spectra with those from the young metal-rich single stellar population (SSP) models. For old clusters we built non-parameter random forest models between the spectral principal components and/or multi-band colours and the parameters of the clusters based on a training data set constructed from the SSP models. The ages and metallicities of the old clusters are then estimated by fitting their observed spectral principal components extracted from the LAMOST spectra and multi-band colours from the photometric measurements with the resultant random forest models. We derived parameters of 53 young and 293 old clusters in our catalogue. Our resultant parameters are in good agreement with those from the literature. The ages of ~30 catalogued clusters and metallicities of ~40 sources are derived for the first time.2021A&A...645A.115Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/645/A115CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/645/A115https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/645/A115http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/645/A115https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/645/A115https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/645/A115http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/645/A115GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/645/A115/table1 (Cluster names, positions and parameters)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/645/A115/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/645/A115/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/645/A115/table1?GETtext/xml+votable180.050000true10.0107341.19820.0055555555555555565/655 666 676 6/2155 2272 2567 2586 2589 2598 2607 2610-2611 2616 2618-2619 2624 2646 2656 2663 2668 2674 2690 2694-2695 2701 2708-2710 2712-2713 2729 2752-2753 2755 27572.0186167556315263e-19 6.090060298487514e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/645/A115?format=asciiOpticaldefaultJ/A+A/645/A115/table1Cluster names, positions and parametersSimbadNameSimbad column added by the CDSmeta.idcharzSmag? SDSS z magnitudemagphot.mag;em.opt.IdoublenullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName of the star cluster in the cataloguemeta.id;meta.maincharRAJ2000Right Ascension (J2000)degpos.eq.ra;meta.mainDEJ2000Declination (J2000)degpos.eq.dec;meta.maincmag? BATC c magnitudemagphot.mag;em.opt.Bdoublenullablee_cmag? BATC c magnitude errormagstat.error;phot.magdoublenullabledmag? BATC d magnitudemagphot.mag;em.opt.Bdoublenullablee_dmag? BATC d magnitude errormagstat.error;phot.magdoublenullableemag? BATC e magnitudemagphot.mag;em.opt.Vdoublenullablee_emag? BATC e magnitude errormagstat.error;phot.magdoublenullablefmag? BATC f magnitudemagphot.mag;em.opt.Vdoublenullablee_fmag? BATC f magnitude errormagstat.error;phot.magdoublenullablegmag? BATC g magnitudemagphot.mag;em.opt.Vdoublenullablee_gmag? BATC g magnitude errormagstat.error;phot.magdoublenullablehmag? BATC h magnitudemagphot.mag;em.opt.Vdoublenullablee_hmag? BATC h magnitude errormagstat.error;phot.magdoublenullableimag? BATC i magnitudemagphot.mag;em.opt.Rdoublenullablee_imag? BATC i magnitude errormagstat.error;phot.magdoublenullablejmag? BATC j magnitudemagphot.mag;em.opt.Rdoublenullablee_jmag? BATC j magnitude errormagstat.error;phot.magdoublenullablekmag? BATC k magnitudemagphot.mag;em.opt.Rdoublenullablee_kmag? BATC k magnitude errormagstat.error;phot.magdoublenullablemmag? BATC m magnitudemagphot.mag;em.opt.Idoublenullablee_mmag? BATC m magnitude errormagstat.error;phot.magdoublenullablenmag? BATC n magnitudemagphot.mag;em.opt.Idoublenullablee_nmag? BATC n magnitude errormagstat.error;phot.magdoublenullableomag? BATC o magnitudemagphot.mag;em.opt.Idoublenullablee_omag? BATC o magnitude errormagstat.error;phot.magdoublenullablepmag? BATC p magnitudemagphot.mag;em.opt.Idoublenullablee_pmag? BATC p magnitude errormagstat.error;phot.magdoublenullableuSmag? SDSS u magnitudemagphot.mag;em.opt.Udoublenullablee_uSmag? SDSS u magnitude errormagstat.error;phot.magdoublenullablegSmag? SDSS g magnitudemagphot.mag;em.opt.Bdoublenullablee_gSmag? SDSS g magnitude errormagstat.error;phot.magdoublenullablerSmag? SDSS r magnitudemagphot.mag;em.opt.Rdoublenullablee_rSmag? SDSS r magnitude errormagstat.error;phot.magdoublenullableiSmag? SDSS i magnitudemagphot.mag;em.opt.Idoublenullablee_iSmag? SDSS i magnitude errormagstat.error;phot.magdoublenullablee_zSmag? SDSS z magnitude errormagstat.error;phot.magdoublenullableE(B-V)? Dust reddening E(B-V)magphot.color.excessfloatnullablelogAge? Resultant age (log t) from this worklog(yr)time.agedoublenullablee_logAge? Uncertainty of the agelog(yr)stat.error;time.agedoublenullable[Fe/H]? Resultant metallicity ([Fe/H]) from this worklog(Sun)phys.abund.Zdoublenullablee_[Fe/H]? Uncertainty of the metallicitylog(Sun)stat.error;phys.abund.FedoublenullableRFclass[0/1] Classification of clusters from the random forest classifiersmeta.codeintClass[0/1] Final classification of clusters in the current workmeta.codeint