Ultrafaint Dwarfs in a Milky Way Context: Introducing the Mint Condition DC Justice League Simulations
Ultrafaint Dwarfs in a Milky Way Context: Introducing the Mint Condition DC Justice League Simulations
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DOI：
10.3847/1538-4357/abcafa
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发表时间：
2020-08
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通讯作者：
Elaad Applebaum;A. Brooks;C. Christensen;F. Munshi;T. Quinn;S. Shen;M. Tremmel
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作者：
Elaad Applebaum;A. Brooks;C. Christensen;F. Munshi;T. Quinn;S. Shen;M. Tremmel
我们介绍了银河系类放大宇宙学模拟的“Mint”分辨率DC Justice League套件的结果，该模拟首次将我们对附近星系的研究扩展到超暗矮星(UFD)区域。这些模拟的质量分辨率是迄今为止发表的最高的宇宙学银河系放大模拟运行到z=0，初始恒星(暗物质)粒子质量为994(17900)M⊙，力分辨率为87pC。我们研究了周围的矮星和UFD，发现模拟结果与用−3>；MV>；−19观测到的星系的动力学性质相匹配，并重现了RH≳200PC的大小-光度平面上的散射。我们预测，通过维拉·鲁宾天文台联合进行的空间和时间遗产调查，附近的绝大多数星系都可以观测到。我们还发现，速度弥散为≲5 Km的弱矮星S−1是由宿主晕的严重潮汐剥离造成的。我们在银河系流体力学的背景下研究了UFD的猝灭，发现大多数UFD在与银河系相互作用之前就被猝灭了，尽管一些猝灭的UFD将其气体保留到坠入。此外，这些模拟还产生了一些独特的矮星，这是第一次被模拟的，例如，富HI场UFD，具有类似于陨石坑2的结构属性的后期形成的UFD，以及在z=0没有暗物质的紧凑矮星。
We present results from the “Mint” resolution DC Justice League suite of Milky Way–like zoom-in cosmological simulations, which extend our study of nearby galaxies down into the ultrafaint dwarf (UFD) regime for the first time. The mass resolution of these simulations is the highest ever published for cosmological Milky Way zoom-in simulations run to z = 0, with initial star (dark matter) particle masses of 994 (17900) M⊙, and a force resolution of 87 pc. We study the surrounding dwarfs and UFDs, and find that the simulations match the observed dynamical properties of galaxies with −3 > MV > −19, and reproduce the scatter seen in the size–luminosity plane for rh ≳ 200 pc. We predict the vast majority of nearby galaxies will be observable by the Vera Rubin Observatory’s coadded Legacy Survey of Space and Time. We additionally show that faint dwarfs with velocity dispersions ≲5 km s−1 result from severe tidal stripping of the host halo. We investigate the quenching of UFDs in a hydrodynamical Milky Way context and find that the majority of UFDs are quenched prior to interactions with the Milky Way, though some of the quenched UFDs retain their gas until infall. Additionally, these simulations yield some unique dwarfs that are the first of their kind to be simulated, e.g., an H i-rich field UFD, a late-forming UFD that has structural properties similar to Crater 2, as well as a compact dwarf satellite that has no dark matter at z = 0.