The Sample of Red Supergiants in Twelve Low-Mass Galaxies of the Local Group

TL;DR

This paper compiles the most comprehensive sample of red supergiants in twelve low-mass Local Group galaxies, enabling studies of stellar properties, star formation rates, and initial mass functions across these galaxies.

Contribution

It presents a new, extensive catalog of RSGs in twelve low-mass galaxies, using multi-band photometry and Gaia data to accurately identify and analyze these stars.

Findings

Identified 2,190 RSGs in ten dwarf galaxies.

Detected 4,823 RSGs in the LMC.

Found 2,138 RSGs in the SMC.

Abstract

This work establishes the most complete sample of red supergiants (RSGs) in twelve low-mass galaxies (WLM, IC 10, NGC 147, NGC 185, IC 1613, Leo A, Sextans B, Sextans A, NGC 6822, Pegasus Dwarf, SMC and LMC) of the Local Group, which forms the solid basis to study the properties of RSGs as well as the star formation rate (SFR) and initial mass function (IMF) of the galaxies. After removing the foreground dwarf stars by their obvious branch in the near-infrared color-color diagram ($(J-H)_0/(H-K)_0$) with the UKIRT/WFCAM and 2MASS photometry as well as the Gaia/EDR3 measurements of proper motion and parallax, RSGs are identified from their location in the color-magnitude diagram $(J-K)_{0}/K_{0}$ of the member stars of the specific galaxy. A total of 2,190 RSGs are found in ten dwarf galaxies, and additionally 4,823 and 2,138 RSGs in the LMC and SMC respectively. The locations of the tip of the red giant branch in the $(J-K)_{0}/K_{0}$ diagram are determined to serve as an indicator of the metallicity and distance modulus of the galaxies.