Near-infrared photometry and spectroscopy of the low Galactic latitude globular cluster 2MASS-GC03

TL;DR

This study uses near-infrared photometry and spectroscopy to analyze the properties, distance, and potential elongation of the globular cluster 2MASS-GC03 near the Galactic disk, confirming its old age and globular cluster status.

Contribution

First detailed near-infrared photometric and spectroscopic analysis of 2MASS-GC03, revealing its metallicity, velocity, distance, and structural hints.

Findings

Metallicity of [Fe/H] = -0.9 +- 0.2

Distance estimated at 10.8 kpc

Cluster age approximately 11.3 Gyr

Abstract

We present deep near-infrared photometry and spectroscopy of the globular cluster 2MASS-GC03 projected in the Galactic disk using MMIRS on the Clay telescope (Las Campanas Observatory) and VISTA Variables in the Via Lactea survey (VVV) data. Most probable cluster member candidates were identified from near-infrared photometry. Out of ten candidates that were followed-up spectroscopically, five have properties of cluster members, from which we calculate <[Fe/H]> = -0.9 +- 0.2 and a radial velocity of v_r > = -78 +- 12km/s. A distance of 10.8kpc is estimated from 3 likely RRLyrae members. Given that the cluster is currently at a distance of 4.2kpc from the Galactic center, the cluster's long survival time of an estimated 11.3 +- 1.2Gyr strengthens the case for its globular-cluster nature. The cluster has a hint of elongation in the direction of the Galactic center.