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The comparative chemical evolution of an isolated dwarf galaxy: a vlt and keck spectroscopic survey of wlm

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journal contribution
posted on 2023-05-17, 19:18 authored by Leaman, R, Venn, KA, Brooks, AM, Battaglia, G, Andrew ColeAndrew Cole, Ibata, RA, Irwin, MJ, McConnachie, AW, Mendel, JT, Starkenburg, E, Tolstoy, E
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 red giant branch 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 ± 0.02 and an intrinsic spread in metallicity of σ = 0.38 ± 0.04 dex, similar to the mean and spread observed in the massive dSph Fornax and the Small Magellanic Cloud. Thus, despite WLM's isolated environment, its global metallicity still follows expectations for 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 d[Fe/H]/drc = –0.04 ± 0.04 dex rc-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.

History

Publication title

Astrophysical Journal

Volume

767

Article number

131

Number

131

Pagination

1-16

ISSN

0004-637X

Department/School

School of Natural Sciences

Publisher

Univ Chicago Press

Place of publication

1427 E 60Th St, Chicago, USA, Il, 60637-2954

Rights statement

Copyright 2013 The American Astronomical Society

Repository Status

  • Open

Socio-economic Objectives

Expanding knowledge in the physical sciences

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