Document Type
Article
Publication Date
1-28-2021
Abstract
We present new Hubble Space Telescope WFC3 near-IR observations of the color-magnitude diagrams (CMDs) in two low-surface-brightness galaxies, F575-3 and F615-1, notable for having no current star formation based on a lack of Ha emission. Key features of the near-IR CMDs are resolved, such as the red giant branch (RGB), the asymptotic giant branch (AGB) region, and the top of the blue main sequence. F575-3 has the bluest RGB of any CMD in the literature, indicating an extremely low mean metallicity. F615-1 has unusually wide RGB and AGB sequences, suggesting multiple episodes of star formation from metal-poor gas, and possibly infalling material. Both galaxies have an unusual population of stars to the red of the RGB and lower in luminosity than typical AGB stars. These stars have normal optical colors but abnormal near-IR colors. We suggest that this population of stars might be analogous to local peculiar stars like Be stars with strong near-IR excesses owing to a surrounding disk of hot gas.
Keywords
stellar populations, galaxy stellar content, galaxy photometry
Publication Title
Astronomical Journal
Grant
AST 0908370
Rights
© 2021. The American Astronomical Society. All rights reserved. This content is free to access, download, and share. For all other uses, you must obtain permission to reuse content: https://journals.aas.org/article-charges-and-copyright/#AAS_material
Recommended Citation
Anomalous Stellar Populations in Low-Surface-Brightness Galaxies. James Schombert and Stacy McGaugh 2021 AJ 161 91
Manuscript Version
Final Publisher Version