Astronomy & Astrophysics
https://doi.org/10.1051/0004-6361/202556457
Sanjaya Paudel1,2 , Cristiano G. Sabiu3 , Suk-Jin Yoon1,2,*, Patrick R. Durrell4, and Nau Raj Pokhrel5
ABSTRACT
Understanding the quenching mechanisms in dwarf galaxies is crucial for constraining models of galaxy formation and evolution. Isolated dwarf galaxies o er valuable insight by helping disentangle the relative roles of internal and environmental processes in shutting down star formation. Here we report the discovery of a quiescent early-type dwarf galaxy (dE), SDSS J011754.86+095819.0 (hereafter dE01+09), located in a nearly isolated environment at a projected distance of approximately one megaparsec from its most likely host group, the NGC524 group. dE01+09 has Mr = 15:72 and g r = 0:67 mag and its light profile is well described by a Sérsic function with an index n = 1:1, consistent with typical dEs. Using optical spectroscopy from the DESI survey, we derived its simple stellar population properties, and found an intermediate luminosity-weighted age of 8.3 1.4 Gyr and a subsolar metallicity of 1:19 0.21 dex, characteristics comparable to those of classical quiescent dEs. We propose that NGC524 may represent an extreme example of group dynamics, in which a member galaxy, dE01+09, was ejected from its host group and subsequently evolved as an isolated system in the field.
Key words. galaxies: dwarf – galaxies: groups: general – galaxies: interactions
