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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 742761.0, MPI für Astronomie / Publikationen_mpia
NIHAO - XI. Formation of ultra-diffuse galaxies by outflows
Authors:Di Cintio, A.; Brook, C. B.; Dutton, A. A.; Macciò, A. V.; Obreja, A.; Dekel, A.
Date of Publication (YYYY-MM-DD):2017
Title of Journal:Monthly Notices of the Royal Astronomical Society
Issue / Number:1
Start Page:L1
End Page:L6
Audience:Not Specified
Abstract / Description: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 Sérsic index of 0.83, a typical distribution of halo spin and concentration, and a non-negligible H I gas mass of 107 - 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.
Free Keywords:galaxies: dwarf; galaxies: evolution; galaxies: formation; galaxies: haloes
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:ISSN:0035-8711 %R 10.1093/mnrasl/slw210
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