标题： 宇宙学流体动力学模拟中的卤素展开：向大质量螺旋星系中密度陡增/平坦问题的重子解决方案迈进 显示英文标题

标题： Halo expansion in cosmological hydro simulations: towards a baryonic solution of the cusp/core problem in massive spirals

摘要： 冷暗物质模型的一个明确预测是，在所有质量尺度上都存在尖峰状的暗物质晕密度分布。 这与螺旋星系观测到的旋转曲线不一致，挑战了原本成功的CDM范式在小尺度上的适用性。 在本工作中，我们使用高分辨率宇宙学流体动力学模拟来研究耗散过程对类似银河系天体（质量约为1e12 Msun）内部暗物质分布的影响。 我们的模拟包括超新星反馈，以及大质量恒星在爆发为超新星之前的辐射压效应。 增强的恒星反馈导致暗物质晕膨胀，而不是相对于N体模拟发生收缩。 重子物质能够消除暗物质的尖峰分布，在质量较大的类似银河系晕的中心几kpc范围内形成平坦、有核心的暗物质密度分布。 该分布可以用Burkert分布很好地拟合，拟合参数与观测结果一致。 此外，我们还得到了平坦的旋转曲线以及扩展的指数型恒星盘分布。 虽然我们得到的恒星盘仍然部分过厚，无法完全 resemble 银河系薄盘，但这项初步研究显示，在大质量盘星系中，重子组分中存在足够的能量来改变暗物质分布，为长期存在的尖峰与核心问题提供了一个可能的解决方案。 显示英文摘要

摘要： A clear prediction of the Cold Dark Matter model is the existence of cuspy dark matter halo density profiles on all mass scales. This is not in agreement with the observed rotation curves of spiral galaxies, challenging on small scales the otherwise successful CDM paradigm. In this work we employ high resolution cosmological hydro-dynamical simulations to study the effects of dissipative processes on the inner distribution of dark matter in Milky-Way like objects (M~1e12 Msun). Our simulations include supernova feedback, and the effects of the radiation pressure of massive stars before they explode as supernovae. The increased stellar feedback results in the expansion of the dark matter halo instead of contraction with respect to N-body simulations. Baryons are able to erase the dark matter cuspy distribution creating a flat, cored, dark matter density profile in the central several kpc of a massive Milky-Way like halo. The profile is well fit by a Burkert profile, with fitting parameters consistent with the observations. In addition, we obtain flat rotation curves as well as extended, exponential stellar disk profiles. While the stellar disk we obtain is still partially too thick to resemble the MW thin disk, this pilot study shows that there is enough energy available in the baryonic component to alter the dark matter distribution even in massive disc galaxies, providing a possible solution to the long standing problem of cusps vs. cores.