FSR1767 - a new globular cluster in the Galaxy

Abstract

The globular cluster (GC) nature of the recently catalogued candidate FSR 1767 is established in the present work. It results as the closest GC so far detected in the Galaxy. The nature of this object is investigated by means of 2MASS colour-magnitude diagrams (CMDs), the stellar radial density profile (RDP) and proper-motions (PM). The properties are consistent with an intermediate metallicity ($\feh\approx-1.2$) GC with a well-defined turnoff (TO), red-giant branch (RGB) and blue horizontal-branch (HB). The distance of FSR 1767 from the Sun is $\ds\approx1.5$ kpc, and it is located at the Galactocentric distance $\rgc\approx5.7$ kpc. With the space velocity components $(V,W)=(184\pm 14,-43\pm 14)\mathrm{km}{\mathrm{s}}^{-1}$, FSR 1767 appears to be a Palomar-like GC with $\mv\approx-4.7$, that currently lies $\approx 57$ pc below the Galactic plane. The RDP is well represented by a King profile with the core and tidal radii $\rc=0.24\pm0.08$ pc and $\rt=3.1\pm1.0$ pc, respectively, with a small half-light radius $\rh=0.60\pm0.15$ pc. The optical absorption is moderate for an infrared GC, $A_V=6.2\pm 0.3$, which together with its central direction and enhanced contamination explains why it has so far been overlooked.

6 pages, 7 figures. MNRAS Letters, accepted

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• Multi-Conjugate Adaptive Optics VLT imaging of the distant old open cluster FSR1415
• FSR0190 - Another old distant galactic cluster
• A populous intermediate-age open cluster and evidence of an embedded cluster among the FSR globular cluster candidates
• The old Galactic open clusters FSR1716 and Czernik23
• A Probable New Globular Cluster in the Galactic Disk
• UKIRT follow-up observations of the old open cluster FSR0358 (Kirkpatrick1)