# Gaia 1 and 2. A pair of new Galactic star clusters

## TL;DR

This paper reports the discovery of two new star clusters, Gaia 1 and Gaia 2, using Gaia data, highlighting Gaia's unique capabilities in detecting faint Galactic satellites despite previous survey limitations.

## Contribution

The study demonstrates Gaia's effectiveness in identifying faint star clusters through stellar positions alone, revealing objects missed by earlier surveys.

## Key findings

- Discovered Gaia 1 and Gaia 2 star clusters.
- Gaia 1 is a massive, nearby cluster close to Sirius.
- Gaia's high resolution enables detection of faint satellites.

## Abstract

We present the results of the very first search for faint Milky Way satellites in the Gaia data. Using stellar positions only, we are able to re-discover objects detected in much deeper data as recently as the last couple of years. While we do not identify new prominent ultra-faint dwarf galaxies, we report the discovery of two new star clusters, Gaia 1 and Gaia 2. Gaia 1 is particularly curious, as it is a massive (2.2$\times$10$^4$ M$_\odot$), large ($\sim$9 pc) and nearby (4.6 kpc) cluster, situated 10' away from the brightest star on the sky, Sirius! Even though this satellite is detected at significance in excess of 10, it was missed by previous sky surveys. We conclude that Gaia possesses powerful and unique capabilities for satellite detection thanks to its unrivalled angular resolution and highly efficient object classification.