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How typical are the local group dwarf galaxies


Weisz, DR and Dolphin, AE and Dalcanton, JJ and Skillman, ED and Holtzman, J and Williams, BF and Gilbert, KM and Seth, AC and Cole, A and Gogarten, SM and Rosema, K and Karachentsev, ID and McQuinn, KBW and Zaritsky, D, How typical are the local group dwarf galaxies, The Astrophysical Journal: An International Review of Astronomy and Astronomical Physics, 743, (1) Article 8. ISSN 0004-637X (2011) [Refereed Article]

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Copyright 2011 American Astronomical Society

DOI: doi:10.1088/0004-637X/743/1/8


We 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

Item Details

Item Type:Refereed Article
Keywords:galaxies: dwarf — galaxies: evolution — galaxies: formation — galaxies: stellar content – galaxies: Local Group
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:Cosmology and extragalactic astronomy
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Cole, A (Professor Andrew Cole)
ID Code:73369
Year Published:2011
Web of Science® Times Cited:45
Deposited By:Mathematics and Physics
Deposited On:2011-09-28
Last Modified:2017-11-06

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