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arXiv 1111.5620astro-ph.COastro-ph.GA
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宇宙学流体模拟中的晕膨胀:大质量螺旋中尖点/核问题的重子解

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

Andrea V. Maccio', Greg Stinson, Chris B. Brook, James Wadsley, H. M. P. Couchman, Sijing Shen, Brad K. Gibson, Tom Quinn

摘要:

冷暗物质模型的一个明确预测是在所有质量尺度上存在尖状暗物质晕密度分布。这是不符合观察到的旋转曲线的旋涡星系,挑战小尺度上,否则成功的CDM范例。本文采用高分辨率的宇宙流体动力学模拟方法研究了耗散过程对类银河天体(M~ 1 e12 Msun)中暗物质内部分布的影响。我们的模拟包括超新星反馈,以及大质量恒星在爆炸成为超新星之前的辐射压力的影响。增加恒星反馈的结果在膨胀的暗物质晕,而不是收缩相对于N体模拟。重子能够擦除暗物质的尖形分布,在一个巨大的银河状晕的中心几千秒差距处产生一个平坦的、核心的、暗物质密度分布。的配置文件是很好的拟合Burkert配置文件,拟合参数与观察一致。此外,我们得到平坦的旋转曲线以及扩展,指数恒星盘配置文件。虽然我们获得的恒星盘仍然部分太厚,不像MW薄盘,但这项初步研究表明,重子分量中有足够的能量可以改变大质量盘星系中的暗物质分布,为长期存在的尖点与核心问题提供了可能的解决方案。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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