Ultra-diffuse galaxies in the Auriga simulations

Liao, Shihong; Gao, Liang; Frenk, Carlos S; Grand, Robert JJ; Guo, Qi; Gómez, Facundo A; Marinacci, Federico; Pakmor, Rüdiger; Shao, Shi; Springel, Volker

doi:10.1093/mnras/stz2969

Ultra-diffuse galaxies in the Auriga simulations

Liao, Shihong; Gao, Liang; Frenk, Carlos S; Grand, Robert JJ; Guo, Qi; Gómez, Facundo A; Marinacci, Federico; Pakmor, Rüdiger; Shao, Shi; Springel, Volker

Authors

Shihong Liao

Liang Gao

Professor Carlos Frenk c.s.frenk@durham.ac.uk
Professor

Robert JJ Grand

Qi Guo

Facundo A Gómez

Federico Marinacci

Rüdiger Pakmor

Dr Shi Shao shi.shao@durham.ac.uk
Academic Visitor

Volker Springel

Abstract

We investigate the formation of ultra-diffuse galaxies (UDGs) using the Auriga high-resolution cosmological magneto-hydrodynamical simulations of Milky Way-sized galaxies. We identify a sample of 92 UDGs in the simulations that match a wide range of observables such as sizes, central surface brightness, Sérsic indices, colors, spatial distribution and abundance. Auriga UDGs have dynamical masses similar to normal dwarfs. In the field, the key to their origin is a strong correlation present in low-mass dark matter haloes between galaxy size and halo spin parameter. Field UDGs form in dark matter haloes with larger spins compared to normal dwarfs in the field, in agreement with previous semi-analytical models. Satellite UDGs, on the other hand, have two different origins: ∼55% of them formed as field UDGs before they were accreted; the remaining ∼45% were normal field dwarfs that subsequently turned into UDGs as a result of tidal interactions.

Citation

Liao, S., Gao, L., Frenk, C. S., Grand, R. J., Guo, Q., Gómez, F. A., …Springel, V. (2019). Ultra-diffuse galaxies in the Auriga simulations. Monthly Notices of the Royal Astronomical Society, 490(4), 5182-5195. https://doi.org/10.1093/mnras/stz2969

Journal Article Type	Article
Acceptance Date	Oct 18, 2019
Online Publication Date	Oct 23, 2019
Publication Date	Dec 31, 2019
Deposit Date	Oct 29, 2019
Publicly Available Date	Oct 29, 2019
Journal	Monthly Notices of the Royal Astronomical Society
Print ISSN	0035-8711
Electronic ISSN	1365-2966
Publisher	Royal Astronomical Society
Peer Reviewed	Peer Reviewed
Volume	490
Issue	4
Pages	5182-5195
DOI	https://doi.org/10.1093/mnras/stz2969

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This article has been accepted for publication in the Monthly notices of the Royal Astronomical Society ©: 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.