Chemical enrichment in very low metallicity environments: Boötes I
Date Issued
2015
Author(s)
Description
The authors are indebted to the Virgo Consortium, which was responsible for designing and running the halo simulations of the Aquarius Project. Additionally, they are grateful to Gabriella De Lucia, Amina Helmi and Yang-Shyang Li for their role in developing the semi-analytic model of galaxy formation used in this paper. DR thanks Francesca Matteucci for countless discussions on chemical evolution and wise advice. Finally, we wish to thank the anonymous referee for comments that improved the presentation of the paper. DR and ES are indebted to the International Space Science Institute (ISSI), Bern, Switzerland, for supporting and funding the international team ‘First stars in dwarf galaxies’. MB and DR acknowledge financial support from PRIN MIUR 2010–2011, project ‘The Chemical and Dynamical Evolution of the Milky Way and Local Group Galaxies’, prot. 2010LY5N2T. DR acknowledges support from PRIN INAF 2010, project ‘Looking for the elusive building blocks of the Milky Way and Andromeda Halos’. RL acknowledges financial support to the DAGAL network from the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007- 2013/ under REA grant agreement number PITN-GA-2011-289313. ES gratefully acknowledges the Canadian Institute for Advanced Research (CIfAR) Global Scholar Academy for support.
Abstract
We present different chemical evolution models for the ultrafaint dwarf galaxy Boötes I. We either assume that the galaxy accretes its mass through smooth infall of gas of primordial chemical composition (classical models) or adopt mass accretion histories derived from the combination of merger trees with semi-analytical modelling (cosmologically-motivated models). Furthermore, we consider models with and without taking into account inhomogeneous mixing in the interstellar medium within the galaxy, i.e. homogeneous versus inhomogeneous models. The theoretical predictions are then compared to each other and to the body of the available data. From this analysis, we confirm previous findings that Boötes I has formed stars with very low efficiency but, at variance with previous studies, we do not find a clear-cut indication that supernova explosions have sustained long-lasting galactic-scale outflows in this galaxy. Therefore, we suggest that external mechanisms such as ram pressure stripping and tidal stripping are needed to explain the absence of neutral gas in Boötes I today.
Volume
446
Issue
4
Start page
4220
Issn Identifier
0035-8711
Ads BibCode
2015MNRAS.446.4220R
Rights
open.access
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