Candidate RR Lyrae Associated with the Ultrafaint Dwarf Galaxy Aquarius III

Fuente: arXiv
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Autores principales: Ngeow, Chow-Choong, Bhardwaj, Anupam
Formato: Preprint
Publicado: 2025
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author Ngeow, Chow-Choong
Bhardwaj, Anupam
author_facet Ngeow, Chow-Choong
Bhardwaj, Anupam
contents We report the search of RR Lyrae in the vicinity of a newly discovered ultrafaint dwarf galaxy, Aquarius III. Based on the known RR Lyrae catalogs and $gri$-band light curves retrieved from public archives, we identified a RR Lyrae with distance, metallicity, and proper motion consistent with Aquarius III. Therefore, this RR Lyrae is the first variable star identified to be associated with Aquarius III, despite its projected distance is more than 15 times the half-light radius of Aquarius III. On the other hand, a dedicated time-series monitoring of the central part of Aquarius III, out to a projected radius of approximately four half-light radius, revealed there is no RR Lyrae in this region. We ran a set of synthetic color-magnitude diagrams with properties similar to Aquarius III, and found a non-negligible probability that Aquarius III could have (at least one) RR Lyrae. We have also identified a RR Lyrae candidate but most likely it is a background halo star.
format Preprint
id arxiv_https___arxiv_org_abs_2502_03764
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Candidate RR Lyrae Associated with the Ultrafaint Dwarf Galaxy Aquarius III
Ngeow, Chow-Choong
Bhardwaj, Anupam
Astrophysics of Galaxies
Solar and Stellar Astrophysics
We report the search of RR Lyrae in the vicinity of a newly discovered ultrafaint dwarf galaxy, Aquarius III. Based on the known RR Lyrae catalogs and $gri$-band light curves retrieved from public archives, we identified a RR Lyrae with distance, metallicity, and proper motion consistent with Aquarius III. Therefore, this RR Lyrae is the first variable star identified to be associated with Aquarius III, despite its projected distance is more than 15 times the half-light radius of Aquarius III. On the other hand, a dedicated time-series monitoring of the central part of Aquarius III, out to a projected radius of approximately four half-light radius, revealed there is no RR Lyrae in this region. We ran a set of synthetic color-magnitude diagrams with properties similar to Aquarius III, and found a non-negligible probability that Aquarius III could have (at least one) RR Lyrae. We have also identified a RR Lyrae candidate but most likely it is a background halo star.
title Candidate RR Lyrae Associated with the Ultrafaint Dwarf Galaxy Aquarius III
topic Astrophysics of Galaxies
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2502.03764