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首页> 外文期刊>The Astrophysical journal >RESPONSE OF DARK MATTER HALOS TO CONDENSATION OF BARYONS: COSMOLOGICAL SIMULATIONS AND IMPROVED ADIABATIC CONTRACTION MODEL
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RESPONSE OF DARK MATTER HALOS TO CONDENSATION OF BARYONS: COSMOLOGICAL SIMULATIONS AND IMPROVED ADIABATIC CONTRACTION MODEL

机译：暗物质晕对巴里昂斯冷凝的响应：宇宙学模拟和改进的绝热吸收模型

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The cooling of gas in the centers of dark matter halos is expected to lead to a more concentrated dark matter distribution. The response of dark matter to the condensation of baryons is usually calculated using the model of adiabatic contraction, which assumes spherical symmetry and circular orbits. In contrast, halos in the hierarchical structure formation scenarios grow via multiple violent mergers and accretion along filaments, and particle orbits in the halos are highly eccentric. We study the effects of the cooling of gas in the inner regions of halos using high-resolution cosmological simulations that include gas dynamics, radiative cooling, and star formation. We find that the dissipation of gas indeed increases the density of dark matter and steepens its radial profile in the inner regions of halos compared to the case without cooling. For the first time, we test the adiabatic contraction model in cosmological simulations and find that the standard model systematically overpredicts the increase of dark matter density in the inner 5% of the virial radius. We show that the model can be improved by a simple modification of the assumed invariant from M(r)r to M(r)r, where r and r are the current and orbit-averaged particle positions. This modification approximately accounts for orbital eccentricities of particles and reproduces simulation profiles to within 10%-20%. We present analytical fitting functions that accurately describe the transformation of the dark matter profile in the modified model and can be used for interpretation of observations.
机译：暗物质光环中心的气体冷却有望导致暗物质分布更加集中。暗物质对重子凝结的响应通常使用绝热收缩模型来计算，该模型具有球形对称性和圆形轨道。相比之下，分层结构形成方案中的光环是通过多次剧烈的合并和沿细丝的堆积而增长的，并且光环中的粒子轨道高度偏心。我们使用包括气体动力学，辐射冷却和恒星形成在内的高分辨率宇宙学研究方法研究了光环内部区域气体冷却的影响。我们发现，与没有冷却的情况相比，气体的散发确实增加了暗物质的密度，并使晕圈内部区域的暗态轮廓变陡。第一次，我们在宇宙学模拟中测试了绝热收缩模型，发现标准模型系统地过度预测了病毒半径内5％内暗物质密度的增加。我们表明，可以通过简单修改从M（r）r到M（r）r的假设不变性来改进模型，其中r和r是当前和轨道平均粒子位置。此修改大约解释了粒子的轨道偏心率，并将模拟轮廓重现到10％-20％以内。我们提出了分析拟合函数，该函数可以准确地描述改进模型中暗物质轮廓的转换，并且可以用于解释观测结果。

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