Phat ELVIS: The inevitable effect of the Milky Way’s disc on its dark matter subhaloes
Phat ELVIS: The inevitable effect of the Milky Way’s disc on its dark matter subhaloes
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DOI：
10.1093/mnras/stz1553
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发表时间：
2018-11
影响因子：
4.8
通讯作者：
Tyler Kelley;J. Bullock;S. Garrison-Kimmel;M. Boylan-Kolchin;M. Pawlowski;A. Graus
中科院分区：
文献类型：
--
作者：
Tyler Kelley;J. Bullock;S. Garrison-Kimmel;M. Boylan-Kolchin;M. Pawlowski;A. Graus
我们介绍了ELVIS项目的扩展，以解释银河系对它的subhalo人口的影响。我们的模拟套件Phat ELVIS包括12个高分辨率的宇宙学纯暗物质（DMO）变焦模拟银河系大小的ΛCDM晕[Mv =（0.7−2）× 1012 M沿着有12个重新运行的嵌入星系势，以匹配今天观察到的银河系盘和凸起。中心星系的潜力破坏subhalos轨道上的小pericentres在每个晕，无论星系质量的比率晕质量。这有几个重要的含义。(1)大多数圆盘运行在20 kpc内没有大于Vmax = 4.5 km s−1的子晕，并且明显缺乏追溯到208 Gyr的子结构，这表明来自黑暗子结构的局部流加热信号将是罕见的。(2)来自盖亚数据的银河系卫星的近心分布是非常相似的近心分布的subhaloes在光盘运行，而DMO运行大大高估星系的近心小于20千秒差距。(3)加强的破坏产生了与经典的“失踪卫星”问题相反的紧张局势：为了解释距离银河系30千秒差距以内的超暗星系，我们必须填充Vpeak为1.77 km s-1的晕（M = 3 × 107 M），远低于原子冷却极限V_\mathrm{peak}\simeq 16 \，{\rm km} \，{\rm s}^{-1}$（M = 5 × 108 M）。(4)如果这样的小晕确实有超暗矮星，这意味着在银河系300 kpc内存在1000个卫星星系。
We introduce an extension of the ELVIS project to account for the effects of the Milky Way galaxy on its subhalo population. Our simulation suite, Phat ELVIS, consists of 12 high-resolution cosmological dark matter-only (DMO) zoom simulations of Milky Way-size ΛCDM haloes [Mv = (0.7−2) × 1012 M⊙] along with 12 re-runs with embedded galaxy potentials grown to match the observed Milky Way disc and bulge today. The central galaxy potential destroys subhalos on orbits with small pericentres in every halo, regardless of the ratio of galaxy mass to halo mass. This has several important implications. (1) Most of the Disc runs have no subhaloes larger than Vmax = 4.5 km s−1 within 20 kpc and a significant lack of substructure going back ∼8 Gyr, suggesting that local stream-heating signals from dark substructure will be rare. (2) The pericentre distributions of Milky Way satellites derived from Gaia data are remarkably similar to the pericentre distributions of subhaloes in the Disc runs, while the DMO runs drastically overpredict galaxies with pericentres smaller than 20 kpc. (3) The enhanced destruction produces a tension opposite to that of the classic ‘missing satellites’ problem: in order to account for ultra-faint galaxies known within 30 kpc of the Galaxy, we must populate haloes with Vpeak ≃ 7 km s−1 (M ≃ 3 × 107 M⊙ at infall), well below the atomic cooling limit of $V_\mathrm{peak}\simeq 16 \,{\rm km} \, {\rm s}^{-1}$ (M ≃ 5 × 108M⊙ at infall). (4) If such tiny haloes do host ultra-faint dwarfs, this implies the existence of ∼1000 satellite galaxies within 300 kpc of the Milky Way.