File(s) under permanent embargo
How typical are the local group dwarf galaxies
journal contribution
posted on 2023-05-17, 08:23 authored by Weisz, DR, Dolphin, AE, Dalcanton, JJ, Skillman, ED, Holtzman, J, Williams, BF, Gilbert, KM, Seth, AC, Andrew ColeAndrew Cole, Gogarten, SM, Rosema, K, Karachentsev, ID, McQuinn, KBW, Zaritsky, DWe compare the cumulative star formation histories (SFHs) of Local Group (LG) dwarf galaxies with those in the volume-limited ACS Nearby Galaxy Survey Treasury (ANGST) sample (D < 4 Mpc), in order to understand how typical the LG dwarf galaxies are relative to those in the nearby universe. The SFHs were derived in a uniform manner from high quality optical color-magnitude diagrams constructed from Hubble Space Telescope imaging. We find that the {\it mean} cumulative SFHs of the LG dwarfs are comparable to the mean cumulative SFHs of the ANGST sample for the three different morphological types (dwarf spheroidals/ellipticals: dSph/dE; dwarf irregulars: dI; transition dwarfs: dTrans). We also discuss effects such as population gradients and systematic uncertainties in the stellar models that may influence the derived SFHs. Both the ANGST and Local Group dwarf galaxies show a consistent and strong morphology-density relationship, emphasizing the importance of environment in the evolution of dwarf galaxies. Specifically, we confirm that dIs are found at lower densities and higher luminosities than dSphs, within this large sample. We also find that dTrans are located in similar environments to those occupied by dwarf irregular galaxies, but have systematically lower luminosities that are more comparable to those of dwarf spheroidals. The similarity of the SFHs and morphology-density relationships of the LG and ANGST dwarf galaxies suggests that the LG dwarfs are a good representation of dwarf galaxies in the local universe
History
Publication title
The Astrophysical Journal: An International Review of Astronomy and Astronomical PhysicsVolume
743Article number
8Number
8Pagination
1-8ISSN
0004-637XDepartment/School
School of Natural SciencesPublisher
Institute of Physics Publishing IncPlace of publication
United StatesRights statement
Copyright 2011 American Astronomical SocietyRepository Status
- Restricted