J/A+A/649/A138ivo://CDS.VizieR/J/A+A/649/A138doi:10.26093/cds/vizier.36490138CDSWang S.Ma J.2022-05-17T08:36:51Z2021-05-28T08:17:18ZCDS support team

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

cds-question@unistra.frgalaxiesglobular-star-clusterssurface-photometryhst-photometryResearching the properties of the brightest globular cluster (referred to as GC1) in M 81 can provide a fossil record of the earliest stages of galaxy formation and evolution. The Beijing-Arizona-Taiwan-Connecticut (BATC) Multicolour Sky Survey has carried out deep exposures of M 81. We derive the magnitudes in intermediate-band filters of the BATC system for GC1 and determine its age, mass, and structural parameters. GC1 was observed by BATC using 14 intermediate-band filters covering a wavelength range of 4000-10000{AA}. Based on photometric data in BATC and Two Micron All Sky Survey near-infrared JHKs filters, we constructed an extensive spectral energy distribution of GC1, spanning the wavelength range from 4000 to 20000{AA}. By comparing multicolour photometry with theoretical single stellar population synthesis models, we derived the age and mass of GC1. In addition, we obtained ellipticities, position angles, and surface brightness profiles for GC1 based on the images of deep observations with the Advanced Camera for Surveys on the Hubble Space Telescope. GC1 is better fitted by the Wilson model than by the King and Sersic models in the F606W filter, and it is better fitted by the Sersic model than by the King and Wilson models in the F814W filter. The 'best-fit' half-light radius of GC1 obtained here is 5.59pc, which is larger than the majority of normal globular clusters (GCs) of the same luminosity. The age and mass of GC1 estimated here are 13.0+/-2.90Gyr and 1.06-1.48x10^7^M_{sun}_, respectively. The Rh versus MV diagram shows that GC1 occupies the same area as extended star clusters. Therefore, we suggest that GC1 is more likely an accreted former nuclear star cluster than a classical GC similar to most of those in the Milky Way.2021A&A...649A.138Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/649/A138CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/AJ/109/1055 : Globulars of M81 (Perelmuter+ 1995)J/MNRAS/405/1293 : Compact star clusters in M81 (Santiago-Cortes+, 2010)J/AJ/139/2620 : Spectroscopy of M81 globular clusters (Nantais+, 2010)J/AJ/142/183 : HST photometry of globulars in M81 (Nantais+, 2011)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/649/A138https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/649/A138http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/649/A138https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/649/A138https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/649/A138http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/649/A138GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapdefaultJ/A+A/649/A138/table4Intensity profiles for GC1 of M81recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintID[GC1] Name of the globular clustermeta.id;meta.maincharDetector[ACS/WFC] detector of HSTmeta.idcharFilter[F606W F814W] filter of ACS/WFC of HSTmeta.id;instr.filtercharRClustercentric radiusarcsecphys.angSizefloatISurface brightness in intensitysolLum.pc**-2phot.mag.sbdoublee_IUncertainty of intensitysolLum.pc**-2stat.errordoubleFlag[OK DEP BAD] flag for every pointmeta.code.errorchar