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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

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Shihong Liao

Liang Gao

Robert JJ Grand

Qi Guo

Facundo A Gómez

Federico Marinacci

Rüdiger Pakmor

Volker Springel


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.


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.

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


Accepted Journal Article (1 Mb)

Copyright Statement
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.

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