Variable Stars in the giant satellite galaxy Antlia 2
Kathy Vivas, Clara Mart\'inez-V\'azquez, Alistair Walker, Vasily, Belokurov, Ting Li, Denis Erkal

TL;DR
This study identifies 350 variable stars in Antlia 2, revealing its large size, distance, and signs of tidal disruption, with implications for its structure and evolution.
Contribution
It provides a comprehensive catalog of variable stars in Antlia 2 and clarifies its structure and tidal disruption status using updated classifications and Gaia data.
Findings
Antlia 2 contains 318 RR Lyrae and 8 anomalous Cepheids.
The galaxy is very large, extending beyond the observed area.
Distance to Antlia 2 is approximately 124 kpc with a notable distance gradient.
Abstract
We report 350 pulsating variable stars found in four DECam fields ( sq. deg.) covering the Antlia 2 satellite galaxy. The sample of variables includes 318 RR Lyrae stars and eight anomalous Cepheids in the galaxy. Reclassification of several objects designated previously to be RR Lyrae as Anomalous Cepheids gets rid of the satellite's stars intervening along the line of sight. This in turn removes the need for prolific tidal disruption of the dwarf, in agreement with the recently updated proper motion and peri-centre measurements based on Gaia EDR3. There are also several bright foreground RR Lyrae stars in the field, and two distant background variables located kpc behind Antlia 2. We found RR Lyrae stars over the full search area, suggesting that the galaxy is very large and likely extends beyond our observed area. The mean period of the RRab in Antlia 2 is 0.599…
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Taxonomy
TopicsStellar, planetary, and galactic studies · Astronomy and Astrophysical Research · Gamma-ray bursts and supernovae
