Planes of satellites around Milky Way/M31-mass galaxies in the FIRE simulations and comparisons with the Local Group
Planes of satellites around Milky Way/M31-mass galaxies in the FIRE simulations and comparisons with the Local Group
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DOI：
10.1093/mnras/stab955
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发表时间：
2020-10
影响因子：
4.8
通讯作者：
J. Samuel;A. Wetzel;S. Chapman;E. Tollerud;P. Hopkins;M. Boylan-Kolchin;J. Bailin;C. Faucher-Giguère
中科院分区：
文献类型：
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作者：
J. Samuel;A. Wetzel;S. Chapman;E. Tollerud;P. Hopkins;M. Boylan-Kolchin;J. Bailin;C. Faucher-Giguère
我们研究的流行，长寿，和卫星矮星系的飞机的原因，在本集团观察到。我们使用14个银河系/仙女座-（MW/M31）质量的宿主星系的反馈在现实环境-2模拟。我们选择了14个最大的恒星质量的卫星在$d_\marthm {host}\le 300\marthm {\，kpc}$的每个主机和校正的不完整性，从前景星系盘相比，MW。我们发现，MW样平面的空间薄和/或运动学连贯的观察是不常见的，但它们确实存在于我们的模拟。z = 0 - 0.2期间，1- 2%的快照中出现空间薄平面，5%的快照中出现运动学相干平面。这些飞机通常是短暂的，存活不到5亿年。然而，如果我们选择在第一近心点附近有大麦哲伦云状卫星的主机，则具有MW状平面的快照的比例急剧增加到7- 16%，寿命为0.7-1 Gyr，可能是因为卫星的群体吸积。我们发现M31的卫星分布更为常见：对于我们考虑的每个平面度量，M31的卫星位于模拟中值的<$1 σ以内。我们没有发现显着差异，平均卫星平面性孤立的主机与主机在LG样对。重子和暗物质的模拟表现出相似的平面性水平，即使重子晕集中在他们的主机晕。我们的结论是，卫星平面不是一个强大的挑战，ΛCDM宇宙学。
We examine the prevalence, longevity, and causes of planes of satellite dwarf galaxies, as observed in the Local Group. We use 14 Milky Way/Andromeda-(MW/M31) mass host galaxies from the Feedback In Realistic Environments-2 simulations. We select the 14 most massive satellites by stellar mass within $d_\mathrm{host}\le 300\mathrm{\, kpc}$ of each host and correct for incompleteness from the foreground galactic disc when comparing to the MW. We find that MW-like planes as spatially thin and/or kinematically coherent as observed are uncommon, but they do exist in our simulations. Spatially thin planes occur in 1–2 per cent of snapshots during z = 0−0.2, and kinematically coherent planes occur in 5 per cent of snapshots. These planes are generally transient, surviving for <500 Myr. However, if we select hosts with a Large Magellanic Cloud-like satellite near first pericentre, the fraction of snapshots with MW-like planes increases dramatically to 7–16 per cent, with lifetimes of 0.7–1 Gyr, likely because of group accretion of satellites. We find that M31’s satellite distribution is much more common: M31’s satellites lie within ∼1σ of the simulation median for every plane metric we consider. We find no significant difference in average satellite planarity for isolated hosts versus hosts in LG-like pairs. Baryonic and dark matter-only simulations exhibit similar levels of planarity, even though baryonic subhaloes are less centrally concentrated within their host haloes. We conclude that planes of satellites are not a strong challenge to ΛCDM cosmology.