Exploring FSR open cluster candidates within $|\Delta\ell|=20^\circ$ of the Galactic anticentre

TL;DR

This study assesses star cluster candidates near the Galactic anticentre from the FSR catalogue, confirming many as genuine clusters, deriving their properties, and exploring their Galactic distribution to improve understanding of star formation and Galactic structure.

Contribution

It provides a systematic analysis of FSR cluster candidates, confirming their nature, deriving astrophysical parameters, and examining their Galactic distribution for the first time.

Findings

A significant fraction of overdensities are confirmed as star clusters.

Many candidates are newly identified open clusters.

Cluster properties correlate with their Galactic position.

Abstract

We investigate the nature of a sample of star cluster candidates detected as stellar overdensities towards the Galactic anticentre. Taken from the catalogue of Froebrich, Scholz, and Raftery (FSR), the sample contains 28 star cluster candidates located within $|\Delta\ell|=20^\circ$ of the anticentre. These are all the candidates in that sector classified by FSR with a high probability of being star clusters. Our main goals are to determine the fraction of such candidates that are unknown star clusters, to derive their astrophysical parameters, and to investigate the relationship of cluster parameters with position in the Galaxy. When photometric and radial distribution properties are considered together, an important fraction of the stellar overdensities with a fluctuation level $\ga3\sigma$ are shown to be star clusters. Thus, catalogues of star cluster candidates, coupled to the present kind of study, are an important source for identifying unknown open clusters. Such efforts affect the understanding of the star-formation rate, cluster dynamical evolution, and Galactic structure, among others.