Distance and reddening of the Local Group dwarf irregular galaxy NGC 6822

TL;DR

This paper provides new measurements of the distance and extinction of the dwarf galaxy NGC 6822 using Hubble Space Telescope data, refining previous estimates with updated calibration methods.

Contribution

It offers an independent, self-consistent distance estimate for NGC 6822 based on the tip of the red giant branch calibration, improving accuracy over prior measurements.

Findings

Distance to NGC 6822 is 23.54±0.05 mag.

New extinction estimates for two fields in NGC 6822.

Comparison with recent distance measurements shows consistency.

Abstract

On the basis of a new photometric analysis of the Local Group dwarf irregular galaxy NCG 6822 based on observations obtained with the Advanced Camera for Surveys onboard the Hubble Space Telescope, we have obtained a new estimate of the extinction of two fields located in the southeast region of the galaxy. Because of significant differences in the distance estimates to NGC 6822 available in literature, we decided to provide an independent determination of the distance to this galaxy based on an updated and self-consistent theoretical calibration of the tip of the red giant branch brightness. As a result we newly determined the distance to NGC 6822 to be equal to ${\rm(m-M)}_0=23.54\pm 0.05$, and compared our measurement with the most recent determinations of this distance.