测试IllustrisTNG-100中本地群外矮星系向后轨道重建的有效性
Testing the validity of backward orbit reconstruction for outer Local Group dwarf galaxies in IllustrisTNG-100
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中文总结 AI 辅助
研究IllustrisTNG-100模拟中本地群外矮星系向后轨道重建有效性，通过追踪矮星系类似物轨道并与解析模型比较，发现重建轨道与模拟轨道吻合度在一定范围内，残余差异或因多种因素，证明外部质量和潮汐场不影响外LG卫星轨道。
中文摘要 AI 辅助
在宇宙学模拟中，银河系（MW）和M31卫星的轨道已被证明与在MW/M31晕扩展势的微调模型中计算的解析轨道相匹配。利用Illustris TNG100模拟中的本地群（LG）类似物样本，我们研究了在LG周转半径（~1 Mpc）附近但在MW和M31的质心半径之外的LG卫星是否也是如此。从仅暗物质（TNG100-Dark）和全流体动力学（TNG100-1）模拟中，我们追踪矮星系类似物的轨道，并将它们与由LG势的解析模型产生的轨道进行比较，该模型由MW和M31的暗物质晕以及在适当情况下它们最大质量的卫星主导。我们发现，在过去6 Gyr中，选定的外LG卫星的重建轨道与模拟轨道的吻合度在lesssim 10%以内，散射随回溯时间增加，到6 Gyr时达到~40%。外LG矮星系的轨道跟踪解析模型这一事实表明，我们的LG类似物外部区域的任何额外质量或LG周围的潮汐场都不会影响外LG卫星的轨道。解析轨道和模拟轨道之间的残余差异可能是由于卫星和MW/M31的质量吸积、MW/M31势的非球形性质以及解析模型中动力学摩擦的规定共同作用的结果。
英文摘要
Orbits of Milky Way (MW) and M31 satellites in cosmological simulations have been shown to match analytic orbits computed in fine-tuned models of the extended potential of the MW/M31 halos. Using a sample of Local Group (LG) analogs from the Illustris TNG100 simulations, we investigate whether the same is true for LG satellites near the periphery of the LG turnaround radius ($\sim 1\,{\rm Mpc}$), but outside the virial radii of the MW and M31. From both dark matter-only (TNG100-Dark) and full hydrodynamical (TNG100-1) simulations, we track the orbits of dwarf galaxy analogs and compare them with orbits resulting from an analytic model of the LG potential, which is dominated by the dark matter halos of the MW and M31, along with, where appropriate, their most massive satellites. We find that the reconstructed orbits of the selected outer LG satellites agree with the simulated orbits to within $\lesssim 10\%$ over the last 6 Gyr, with the scatter increasing with lookback time and reaching $\sim 40\%$ by 6 Gyr. The fact that orbits of outer LG dwarfs track the analytical models suggests that any excess mass in the outer regions of our LG analogs or the tidal field surrounding the LG does not affect the orbits of outer LG satellites. Residual differences between the analytic and simulated orbits are likely due to a combination of mass accretion for the satellites and MW/M31, the non-spherical nature of the MW/M31 potential, and the prescription for dynamical friction in the analytical models.
