Discovery of VVV CL001: A low-mass globular cluster next to UKS 1 in the direction of the Galactic bulge

D. Minniti, M. Hempel, I. Toledo, V. D. Ivanov, J. Alonso-García, R. K. Saito, M. Catelan, D. Geisler, A. Jordán, J. Borissova, M. Zoccali, R. Kurtev, G. Carraro, B. Barbuy, J. Clariá, M. Rejkuba, J. Emerson, C. Moni Bidin

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

Context. It is not known how many globular clusters may remain undetected towards the Galactic bulge. Aims. One of the aims of the VISTA Variables in the Via Lactea (VVV) Survey is to accurately measure the physical parameters of the known globular clusters in the inner regions of the Milky Way and search for new ones, hidden in regions of large extinction. Methods. From deep near-infrared images, we derive deep JHKS-band photometry of a region surrounding the known globular cluster UKS 1 and reveal a new low-mass globular cluster candidate that we name VVV CL001. Results. We use the horizontal-branch red clump to measure E(B - V) ∼ 2.2 mag, (m - M)0 = 16.01 mag, and D = 15.9 kpc for the globular cluster UKS 1. On the basis of near-infrared colour - magnitude diagrams, we also find that VVV CL001 has E(B - V) ∼ 2.0, and that it is at least as metal-poor as UKS 1, although its distance remains uncertain. Conclusions. Our finding confirms the previous projection that the central region of the Milky Way harbours more globular clusters. VVV CL001 and UKS 1 are good candidates for a physical cluster binary, but follow-up observations are needed to decide if they are located at the same distance and have similar radial velocities.

Original languageEnglish
Article numberA81
JournalAstronomy and Astrophysics
Volume527
Issue number10
DOIs
StatePublished - Mar 2011
Externally publishedYes

Keywords

  • globular clusters: general
  • globular clusters: individual: UKS 1
  • globular clusters: individual: VVV CL001
  • surveys

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