تقرير
NIHAO XI: Formation of Ultra-Diffuse Galaxies by outflows
| العنوان: | NIHAO XI: Formation of Ultra-Diffuse Galaxies by outflows |
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| المؤلفون: | Di Cintio, Arianna, Brook, Chris B., Dutton, Aaron A., Macciò, Andrea V., Obreja, Aura C., Dekel, Avishai |
| سنة النشر: | 2016 |
| المجموعة: | Astrophysics |
| مصطلحات موضوعية: | Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics |
| الوصف: | 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 $\rm L_{\star}$ galaxies or diffuse dwarfs, are challenging issues. Using zoom-in cosmological simulations from the NIHAO project, we show that UDG analogues form naturally in medium-mass haloes due to episodes of gas outflows associated with star formation. The simulated UDGs live in isolated haloes of masses $10^{10-11}\rm M_{\odot}$, have stellar masses of $10^{7-8.5}\rm M_{\odot}$, effective radii larger than 1 kpc and dark matter cores. They show a broad range of colors, an average S\'ersic index of 0.83, a typical distribution of halo spin and concentration, and a non-negligible HI gas mass of $10^{7-9}\rm M_{\odot}$, which correlates with the extent of the galaxy. Gas availability is crucial to the internal processes that 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 HI gas than less extended dwarfs of similar $\rm M_{\star}$. Comment: matches accepted version, MNRAS Letter 2016-10-12 |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1093/mnrasl/slw210 |
| URL الوصول: | http://arxiv.org/abs/1608.01327 |
| رقم الأكسشن: | edsarx.1608.01327 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1093/mnrasl/slw210 |
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