Star clusters in the dwarf irregular galaxy Leo A
| Autor: | Alina Leščinskaitė, Vladas Vansevičius, Marius Čeponis, Rokas Naujalis, R. Stonkutė |
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| Rok vydání: | 2019 |
| Předmět: |
Physics
Stellar mass 010308 nuclear & particles physics Metallicity Local Group FOS: Physical sciences Astronomy and Astrophysics Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences Astrophysics - Astrophysics of Galaxies Galaxy Stars Star cluster Leo A Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Astrophysics::Earth and Planetary Astrophysics Irregular galaxy 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics |
| DOI: | 10.48550/arxiv.1909.05934 |
| Popis: | Leo A is an isolated gas-rich dwarf irregular galaxy of low stellar mass and metallicity residing at the outskirts of the Local Group. Ages of the stellar populations in Leo A range from $\sim$10 Myr to $\sim$10 Gyr. So far, only one star cluster has been discovered in this galaxy. Our aim is to search for star cluster candidates in the Leo A galaxy. We performed photometry of star-like objects on HST ACS archive observation frames in the $F475W$ and $F814W$ passbands and studied the spatial clustering of the Leo A stars down to the turn-off point of the old stellar populations. We report the discovery of four star clusters in the Leo A galaxy. This means that now a sample of five star clusters is known in Leo A. Two clusters are of a young age ($\sim$20 Myr; overlapping with HII regions) and low in mass ($\gtrsim$400 M$_\odot$ and $\gtrsim$150 M$_\odot$), the other three clusters are older ($\gtrsim$100 Myr) and also of low mass ($\gtrsim$300 M$_\odot$). These rough estimates are made assuming the isochrones of a metallicity derived for HII regions ($Z=0.0007$). Colour-magnitude diagrams of the stars residing in the circular areas of a 2.5arcsec radius around the clusters and integrated aperture photometry results of the clusters are presented. Comment: 5 pages, 3 figures, 2 tables, accepted for publication in A&A |
| Databáze: | OpenAIRE |
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