# Analysis of the physical nature of 22 New VVV Survey Globular Cluster candidates in the Milky Way Bulge

## TL;DR

This study analyzes 22 new globular cluster candidates in the Milky Way bulge using near-infrared and Gaia data, identifying 17 likely real clusters and highlighting the need for further confirmation.

## Contribution

It provides a detailed characterization of 22 GC candidates with new CMDs and LFs, and confirms the potential reality of Minni 40 as a very close bulge cluster.

## Key findings

- 17 out of 22 candidates are likely real clusters.
- Minni 40 may be the closest GC to the Galactic center.
- Alternative techniques are needed for confirmation.

## Abstract

In order to characterize 22 new globular cluster (GC) candidates in the Galactic bulge, we present their colour-magnitude diagrams (CMDs) and Ks-band luminosity functions (LFs) using the near-infrared VVV database as well as Gaia-DR2 proper motion dataset. CMDs were obtained, on one hand, after properly decontaminating the observed diagrams from background/foreground disc stars and other sources. On the other hand, CMDs were also obtained based upon star selection in proper motion diagrams. Taking into account our deep CMDs and LFs analyses, we find that 17 out of 22 new GC candidates may be real and should therefore be followed-up, while 5 candidates were discarded from the original sample. We also search for RR Lyrae and Mira variable stars in the fields of these new GC candidates. In particular, we confirm that Minni 40 may be a real cluster. If confirmed by further follow-up analysis, it would be the closest GC to the Galactic centre in projected angular distance, located only 0.5 deg away from it. We consider that it is very difficult to confirm the physical reality of these small, poorly-populated bulge GCs so in many cases alternative techniques are needed to corroborate our findings.