Young stellar structures in four nearby galaxies

TL;DR

This study develops a hierarchical cluster detection method to identify young stellar structures across multiple scales in four nearby galaxies, demonstrating the potential of Gaia data for future stellar population analysis.

Contribution

Introduces a modified friends-of-friends algorithm for detecting stellar structures in nearby galaxies, validated across multiple datasets and scales, highlighting Gaia's potential.

Findings

Multiple stellar structures identified in all galaxies

Structures range from a few parsecs to over 1 kiloparsec

Gaia observations will enhance understanding of young stellar populations

Abstract

A cluster finding method was developed and applied in four Local Group Galaxies (SMC, M31, M33 and NGC 6822). The aim is to study the young stellar population of these galaxies by identifying stellar structures in small and large scales. Also our aim is to assess the potential of using the observations of ESA's space mission Gaia for the study of nearby galaxies resolved in stars. The detection method used is a Hierarchical technique based on a modified friends of friends algorithm. The identified clusters are classified in five distinct categories according to their size. The data for our study were used from two ground based surveys, the Local Group Galaxy Survey and the Maggelanic Clouds Spectroscopic Survey. Relatively young main sequence stars were selected from the stellar catalogs and were used by the detection algorithm. Multiple young stellar structures were identified in all galaxies with size varying from very small scales of a few pc up to scales larger than 1 kpc. The same cluster finding method was used in six spiral galaxies observed with the Hubble Space Telescope in a previous study. The average size in each category of the identified structures in the Local Group galaxies presents values consistent with the identified structures in the relatively distant spiral galaxies. Most of the structures consist of stars within the observational limits of Gaia's instruments. It is expected that Gaia's observations will contribute significantly on the study of the young stellar population of nearby galaxies.