Star Formation History of the Local Group Dwarf Irregular Galaxy, NGC 6822

Fuente: arXiv
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Main Authors: Khatamsaz, Fatemeh, Abdollahi, Mahdi, Abdollahi, Hedieh, Javadi, Atefeh, van Loon, Jacco Th.
Format: Preprint
Published: 2024
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author Khatamsaz, Fatemeh
Abdollahi, Mahdi
Abdollahi, Hedieh
Javadi, Atefeh
van Loon, Jacco Th.
author_facet Khatamsaz, Fatemeh
Abdollahi, Mahdi
Abdollahi, Hedieh
Javadi, Atefeh
van Loon, Jacco Th.
contents NGC 6822 is an isolated dwarf irregular galaxy in the local group at a distance of 490 kpc. In this paper, we present the star formation history (SFH) within a field with a radius of 3 kpc, beyond the optical body of the galaxy (1.2 kpc). We utilized a novel method based on evolved asymptotic giant branch (AGB) stars. We collected the Near infrared data of 329 variable stars, including long-period and amplitude variables and Carbon-rich AGB stars. We used stellar evolutionary track and theoretical isochrones to obtain the birth mass, age, and pulsation duration of the detected stars to calculate the star formation rate (SFR) and trace the SFH of the galaxy. We studied the star formation history of the galaxy for the mean metallicity value (Z) of 0.003. We reconstructed the SFH for two regions. The bar region, a central rectangular area, and the outer region, which covers a circular field beyond the bar region and extends to a radius of 3 kpc. Our results show a significant burst of star formation around 2.6 and 2.9 Gyr ago in the bar and outer regions, respectively. Additionally, we observed a notable enhancement in the SFR in the bar region over the past 200 Myr.
format Preprint
id arxiv_https___arxiv_org_abs_2412_05646
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Star Formation History of the Local Group Dwarf Irregular Galaxy, NGC 6822
Khatamsaz, Fatemeh
Abdollahi, Mahdi
Abdollahi, Hedieh
Javadi, Atefeh
van Loon, Jacco Th.
Astrophysics of Galaxies
NGC 6822 is an isolated dwarf irregular galaxy in the local group at a distance of 490 kpc. In this paper, we present the star formation history (SFH) within a field with a radius of 3 kpc, beyond the optical body of the galaxy (1.2 kpc). We utilized a novel method based on evolved asymptotic giant branch (AGB) stars. We collected the Near infrared data of 329 variable stars, including long-period and amplitude variables and Carbon-rich AGB stars. We used stellar evolutionary track and theoretical isochrones to obtain the birth mass, age, and pulsation duration of the detected stars to calculate the star formation rate (SFR) and trace the SFH of the galaxy. We studied the star formation history of the galaxy for the mean metallicity value (Z) of 0.003. We reconstructed the SFH for two regions. The bar region, a central rectangular area, and the outer region, which covers a circular field beyond the bar region and extends to a radius of 3 kpc. Our results show a significant burst of star formation around 2.6 and 2.9 Gyr ago in the bar and outer regions, respectively. Additionally, we observed a notable enhancement in the SFR in the bar region over the past 200 Myr.
title Star Formation History of the Local Group Dwarf Irregular Galaxy, NGC 6822
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2412.05646