An observer's guide to the (Local Group) dwarf galaxies: predictions for their own dwarf satellite populations
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Author(s)
Dooley, Gregory Alan
Peter, Annika H. G.
Yang, Tianyi
Willman, Beth
Griffen, Brendan F.
Frebel, Anna L.
Date Issued
August 2017
Journal
Monthly Notices of the Royal Astronomical Society
Publisher
Oxford University Press (OUP)
Citation
Dooley, Gregory A. et al. “An Observer’s Guide to the (Local Group) Dwarf Galaxies: Predictions for Their Own Dwarf Satellite Populations.” Monthly Notices of the Royal Astronomical Society 471, 4 (August 2017): 4894–4909 © 2018 The Author(s)
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Author's final manuscript
Abstract
A recent surge in the discovery of new ultrafaint dwarf satellites of the Milky Way has inspired the idea of searching for faint satellites, 10³M[subscript ⊙] < M* < 10⁶M[subscript ⊙], around less massive field galaxies in the Local Group. Such satellites would be subject to weaker environmental influences than Milky Way satellites, and could lead to new insights on low-mass galaxy formation. In this paper, we predict the number of luminous satellites expected around field dwarf galaxies by applying several abundance-matching models and a reionization model to the dark-matter only Caterpillar simulation suite. For three of the four abundance-matching models used, we find a > 99 per cent chance that at least one satellite with stellar mass M* > 10⁵M[subscript ⊙] exists around the combined five Local Group field dwarf galaxies with the largest stellar mass. When considering satellites with M* > 10⁴M[subscript ⊙], we predict a combined 5-25 satellites for the five largest field dwarfs, and 10-50 for the whole Local Group field dwarf population. Because of the relatively small number of predicted dwarfs, and their extended spatial distribution, a large fraction each Local Group dwarf's virial volume will need to be surveyed to guarantee discoveries. We compute the predicted number of satellites in a given field of view of specific Local Group galaxies, as a function of minimum satellite luminosity, and explicitly obtain such values for the Solitary Local dwarfs survey. Uncertainties in abundance-matching and reionization models are large, implying that comprehensive searches could lead to refinements of both models.
MIT Department
Massachusetts Institute of Technology. Department of Physics
MIT Kavli Institute for Astrophysics and Space Research
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DOI of Published Version
https://doi.org/10.1093/MNRAS/STX1900
