The Comparative Chemical Evolution of an Isolated Dwarf Galaxy: A VLT and Keck Spectroscopic Survey of WLM
Ryan Leaman, Kim A. Venn, Alyson M. Brooks, Giuseppina Battaglia, Andrew A. Cole, Rodrigo A. Ibata, Mike J. Irwin, Alan W. McConnachie, J. Trevor Mendel, Else S… 展开作者
Ryan Leaman, Kim A. Venn, Alyson M. Brooks, Giuseppina Battaglia, Andrew A. Cole, Rodrigo A. Ibata, Mike J. Irwin, Alan W. McConnachie, J. Trevor Mendel, Else Starkenburg, Eline Tolstoy
备注：
Accepted for Publication in ApJ. 11 Figures, 2 Tables
Building on our previous spectroscopic and photometric analysis of the isolated Local Group dwarf irregular (dIrr) galaxy WLM, we present a comparison of the metallicities of its RGB stars with respect to the well studied Local Group dwarf spheroidal galaxies (dSphs) and Magellanic Clouds. We calculate a mean metallicity of [Fe/H]$ = -1.28 \pm 0.02$, and intrinsic spread in metallicity of $σ= 0.38 \pm 0.04$ dex, similar to the mean and spread observed in the massive dSph Fornax and the Small Magellanic Cloud. Thus, despite its isolated environment the global metallicity still follows expectations for WLM's mass and its global chemical evolution is similar to other nearby luminous dwarf galaxies (gas-rich or gas-poor). The data also show a radial gradient in [Fe/H] of $\rm{d[Fe/H]/dr_{c}} = -0.04 \pm 0.04$ dex $\rm{r_{c}^{-1}}$, which is flatter than that seen in the unbiased and spatially extended surveys of dSphs. Comparison of the spatial distribution of [Fe/H] in WLM, the Magellanic Clouds, and a sample of Local Group dSphs, shows an apparent dichotomy in the sense that the dIrrs have statistically flatter radial [Fe/H] gradients than the low angular momentum dSphs. The correlation between angular momentum and radial metallicity gradient is further supported when considering the Local Group dEs. This chemodynamic relationship offers a new and useful constraint for environment driven dwarf galaxy evolution models in the Local Group.
GMP-selected dual and lensed AGNs: selection function and classification based on near-IR colors and resolved spectra from VLT/ERIS, KECK/OSIRIS, and LBT/LUCI
DESI Strong Lens Foundry IV: Spectroscopic Confirmation of DESI Lens Candidates with VLT/MUSE
University of California, Berkeley（加州大学伯克利分校）；Gemini Observatory / NSF’s NOIRLab（吉米天文台 / 美国国家光学红外天文研究实验室）；University of San Francisco（旧金山大学）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；Institute for Astronomy, University of Hawaii（夏威夷大学天体物理研究所）；University of Pittsburgh（匹兹堡大学）；University of California, Los Angeles（加州大学洛杉矶分校）；Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo（东京大学理化学研究所木下伽利略宇宙物质起源研究机构）
