SIMBAD references

2017MNRAS.466L...1D - Mon. Not. R. Astron. Soc., 466, L1-L6 (2017/March-3)

NIHAO - XI. Formation of ultra-diffuse galaxies by outflows.


Abstract (from CDS):

We address the origin of ultra-diffuse galaxies (UDGs), which have stellar masses typical of dwarf galaxies but effective radii of Milky Way-sized objects. Their formation mechanism, and whether they are failed L* galaxies or diffuse dwarfs, are challenging issues. Using zoom-in cosmological simulations from the Numerical Investigation of a Hundred Astrophysical Objects (NIHAO) project, we show that UDG analogues form naturally in dwarf-sized haloes due to episodes of gas outflows associated with star formation. The simulated UDGs live in isolated haloes of masses 1010–11 M, have stellar masses of 107–8.5 M, effective radii larger than 1 kpc and dark matter cores. They show a broad range of colours, an average Sersic index of 0.83, a typical distribution of halo spin and concentration, and a non-negligible H I gas mass of 10^7 - 9^ M, which correlates with the extent of the galaxy. Gas availability is crucial to the internal processes which form UDGs: feedback-driven gas outflows, and subsequent dark matter and stellar expansion, are the key to reproduce faint, yet unusually extended, galaxies. This scenario implies that UDGs represent a dwarf population of low surface brightness galaxies and should exist in the field. The largest isolated UDGs should contain more H I gas than less extended dwarfs of similar M*.

Abstract Copyright: © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society

Journal keyword(s): galaxies: dwarf - galaxies: evolution - galaxies: formation - galaxies: haloes - galaxies: haloes

Simbad objects: 9

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