Densities and mass assembly histories of the Milky Way satellites are not a challenge to ΛCDM
Densities and mass assembly histories of the Milky Way satellites are not a challenge to ΛCDM
复制标题
银河系卫星的密度和质量组装历史并不是对ÎCDM的挑战
DOI：
10.1093/mnras/stad2219
复制
发表时间：
2023
影响因子：
4.8
通讯作者：
Wu, Zewei
中科院分区：
文献类型：
--
作者：
Kravtsov, Andrey;Wu, Zewei
我们使用GRUMPY星系形成模型，该模型基于对银河系（MW）大小的晕的一系列放大、高分辨率、无耗散的冷暗物质（ΛCDM）模拟，来检查恒星分布半质量半径内的总物质密度，ρtot（<r1/2），MW宿主周围的卫星矮星系及其质量组装历史。我们将模型结果与观测到的银河系矮卫星在整个光度范围内的ρtot（<r1/2）估计值进行了比较。我们发现，观测到的MW矮卫星表现出的趋势，减少总物质密度的半质量半径，ρtot（<r1/2），随着恒星质量的增加。这一趋势与模型预测的趋势基本一致。与我们的基于Λ CDM的模型的结果相比，没有一个观测到的卫星过于密集。我们还表明，虽然许多卫星星系的晕质量与MW祖先atz 10的晕质量相当，在这些早期时期，光环作为卫星生存toz=我们的研究结果表明，无论是观测到的银河系卫星的密度估计，还是它们的质量组装历史，都没有提出一个新的假设。对CDM模式的挑战。事实上，密度趋势与观测星系和模型星系的恒星质量之间的广泛一致性可以被认为是模型的又一个成功。
We use theGRUMPYgalaxy formation model based on a suite of zoom-in, high-resolution, dissipationless Λ Cold Dark Matter (ΛCDM) simulations of the Milky Way (MW) sized haloes to examine total matter density within the half-mass radius of stellar distribution, ρtot(<r1/2), of satellite dwarf galaxies around the MW hosts and their mass assembly histories. We compare model results to ρtot(<r1/2) estimates for observed dwarf satellites of the Milky Way spanning their entire luminosity range. We show that observed MW dwarf satellites exhibit a trend of decreasing total matter density within a half-mass radius, ρtot(<r1/2), with increasing stellar mass. This trend is in general agreement with the trend predicted by the model. None of the observed satellites are overly dense compared to the results of our ΛCDM-based model. We also show that although the halo mass of many satellite galaxies is comparable to the halo mass of the MW progenitor atz≳ 10, at these early epochs halos that survive as satellites toz= 0 are located many virial radii away from the MW progenitors and thus do not have a chance to merge with it. Our results show that neither the densities estimated in observed Milky Way satellites nor their mass assembly histories pose a challenge to the ΛCDM model. In fact, the broad agreement between density trends with the stellar mass of the observed and model galaxies can be considered as yet another success of the model.