Dwarf galaxies

Studying dwarf galaxies is essential for modern cosmology because they offer valuable insights into the formation and evolution of large-scale structures and provide clues about the distribution and nature of dark matter. However, modern cosmology faces challenges that don’t entirely align with the observation of dwarf galaxies. One significant issue is the disparity between the predicted and observed numbers and distributions of dwarf galaxies in the Milky Way and other galaxies.

Early-type dwarf galaxies

Early-type dwarf galaxies (dEs) are low-mass (less than ~109 Msun), non-star-forming, and gas-poor galaxies. They are classically characterized as morphologically smooth and red-colored objects, and they are preferentially found in dense environments such as galaxy groups and clusters. They have a rare appearance in isolation or low-density environments; as such, the extreme environmental-dependent population has been frequently interpreted as the environment-dependent origin of dEs. Moreover, being low-mass galaxies, they are highly susceptible to the environment where they reside, and the environment can act in diverse ways to influence several observational properties of galaxies. Therefore, the study of dEs provides an opportunity to understand the role of the environment in shaping galaxies' evolutionary processes. 

Although dEs are traditionally recognized as smooth galaxies, deep imaging and sophisticated image analysis techniques have revealed several hidden features. Faint spiral arms or bars are frequently found in bright dEs, and a central excess of light, the so-called nucleus, is nearly universal. 

Related Publication:

ApJS 285, 6, 2026 Groups of Dwarf Galaxies in the Local Universe 

ApJL 976:L18, 2024 Discovery of a Rare Group of Dwarf Galaxies in the Local Universe

ApJ 995, 178, 2025 Different Origins of Nucleated and Nonnucleated Dwarf Elliptical Galaxies: Identified by Deep Learning

ApJS 265:57, 2023 An Extensive Catalog of Early-type Dwarf Galaxies in the Local Universe: Morphology and Environment

MNRAS, 413, 1764, (2011), Stellar populations of Virgo cluster early-type dwarf galaxies with and without discs: a dichotomy in age? S. Paudel, T. Lisker, H. Kuntschner, E. Grebel & K. Glatt

ApJL, 724,64, (2010), Nuclei of early-type dwarf galaxies: insights from stellar populations S. Paudel, T. Lisker, & H. Kuntschner

MNRAS, 405, 800, (2010), Nuclei of early-type dwarf galaxies: are they progenitors of UCDs? S. Paudel, T. Lisker, & J. Janz

Students:

• Jin-Ah Kim (Master research student at Yonsei university, Seoul, South Korea)