Inspection of 19 globular cluster candidates in the Galactic bulge with the VVV survey
arXiv:2111.08317 · doi:10.1051/0004-6361/202141819
Abstract
The census of the globular clusters (GCs) in the Milky Way (MW) is still a work in progress. We explore the nature of 19 new GC candidates in the Galactic bulge, based on the analysis of their colour-magnitude diagrams (CMDs) in the near-IR, using the VISTA Variables in the Via Láctea Survey (VVV) database. We estimate their main astrophysical parameters: reddening and extinction, distance, total luminosity, mean cluster proper motions (PMs), metallicity and age. We obtain the cluster catalogues including the likely cluster members by applying a decontamination procedure on the observed CMDs, based upon the vector PM diagrams from VIRAC2. We estimate a wide reddening range of the mag and extinction mag for the sample clusters as expected in the bulge regions. The range of heliocentric distances is kpc. This allows us to place these clusters between 0.56 and 3.25 kpc from the Galactic centre, assuming kpc. Also, their PMs are kinematically similar to the typical motion of the Galactic bulge, apart from VVV-CL160, which shows different PMs. We also derive their metallicities and ages, finding [Fe/H] dex and Gyr respectively. The luminosities are calculated both in and V-bands, recovering . We also examine the possible RR Lyrae members found in the cluster fields. Based on their positions, kinematics, metallicities and ages and comparing our results with the literature, we conclude that 9 candidates are real GCs, 7 need more observations to be fully confirmed as GCs, whereas 3 candidates are discarded for being younger open clusters.
29 pages, 14 figures. Accepted for publication in A&A
References in corpus (26)
- Gaia EDR3 view on Galactic globular clusters
- The Optical to Mid-Infrared Extinction Law Based on the APOGEE, Gaia DR2, Pan-STARRS1, SDSS, APASS, 2MASS and WISE Surveys
- Calibration of the Tip of the Red Giant Branch (TRGB)
- The VISTA Science Archive
- A systematic survey for infrared star clusters with |b|<20deg using 2MASS
- Near-IR properties of 24 Globular Clusters in the Galactic Bulge
- VIRAC: The VVV Infrared Astrometric Catalogue
- The VISTA ZYJHKs Photometric System: Calibration from 2MASS
- Empirical photometric calibration of the Gaia Red Clump: colours, effective temperature and absolute magnitude
- New near-infrared period-luminosity-metallicity relations for RR Lyrae stars and the outlook for Gaia
- New galactic star clusters discovered in the VVV survey. Candidates projected on the inner disk and bulge
- A Deep View of a Fossil Relic in the Galactic Bulge: The Globular Cluster HP1
- A new class of fossil fragments from the hierarchical assembly of the Galactic bulge
- Mapping the stellar age of the Milky Way bulge with the VVV. III. High resolution reddening map
- Ages of the Bulge globular clusters NGC 6522 and NGC 6626 (M28) from HST Proper-motion-cleaned Color-Magnitude Diagrams
- Analysis of the physical nature of 22 New VVV Survey Globular Cluster candidates in the Milky Way Bulge
- Three candidate globular clusters discovered in the Galactic bulge
- The enigmatic globular cluster UKS~1 obscured by the bulge: \textit{H}-band discovery of nitrogen-enhanced stars
- VVVX-Gaia Discovery of a Low Luminosity Globular Cluster in the Milky Way Disk
- Confirmation and physical characterization of the new bulge globular cluster Patchick 99 from the VVV and Gaia surveys
- Discovery of a new nearby globular cluster with extreme kinematics located in the extension of a halo stream
- AL 3 (BH 261): a new globular cluster in the Galaxy
- Dynamical Masses and Stellar Evolutionary Model Predictions of M-Stars
- Physical characterization of recently discovered globular clusters in the Sagittarius dwarf spheroidal galaxy II. Metallicities, ages and luminosities
- The RR Lyrae projected density distribution from the Galactic centre to the halo
- Constraining the Dust Opacity Law in Three Small and Isolated Molecular Clouds