Halo Substructure Boosts to the Signatures of Dark Matter Annihilation
Halo Substructure Boosts to the Signatures of Dark Matter Annihilation
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DOI：
10.3390/galaxies7030068
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发表时间：
2019-03
期刊：
影响因子：
2.5
通讯作者：
S. Ando;T. Ishiyama;N. Hiroshima
中科院分区：
文献类型：
--
作者：
S. Ando;T. Ishiyama;N. Hiroshima
暗物质亚结构的存在将增强暗物质湮灭的信号。我们回顾了基于数值N体模拟和半解析模拟的亚晕增强因子的估计的最新进展。亚晕增强因子是亚晕中湮灭的光度与产生光滑分量的光度之比。由于所有尺度的亚晕，从地球质量(如预期的那样，超对称中性诺，冷暗物质的主要候选者)到星系或更大的星系，对湮灭率都有很大的贡献，因此有必要了解质量超过20个数量级的大动态范围内的亚晕特性。尽管数值模拟在分辨区域中给出了最准确的评估，但在次网格尺度下向下推断次晕属性会带来很大的不确定性--对于星系大小的晕，直接的外推会产生非常大的次晕助推因子≳100。基于扩展的Press-Scheck hter形式和潮汐剥离模型等分析规定的物理激励理论模型，与模拟结果进行了很好的验证，预测星系大小的晕的有序一致性将得到更适度的提升。准确评估加速因子对于间接暗物质搜索是至关重要的，因此，强烈要求在大范围的宿主质量和红移范围内校准模型。
The presence of dark matter substructure will boost the signatures of dark matter annihilation. We review recent progress on estimates of this subhalo boost factor—a ratio of the luminosity from annihilation in the subhalos to that originating the smooth component—based on both numerical N-body simulations and semi-analytic modelings. Since subhalos of all the scales, ranging from the Earth mass (as expected, e.g., the supersymmetric neutralino, a prime candidate for cold dark matter) to galaxies or larger, give substantial contribution to the annihilation rate, it is essential to understand subhalo properties over a large dynamic range of more than twenty orders of magnitude in masses. Even though numerical simulations give the most accurate assessment in resolved regimes, extrapolating the subhalo properties down in sub-grid scales comes with great uncertainties—a straightforward extrapolation yields a very large amount of the subhalo boost factor of ≳100 for galaxy-size halos. Physically motivated theoretical models based on analytic prescriptions such as the extended Press-Schechter formalism and tidal stripping modeling, which are well tested against the simulation results, predict a more modest boost of order unity for the galaxy-size halos. Giving an accurate assessment of the boost factor is essential for indirect dark matter searches and thus, having models calibrated at large ranges of host masses and redshifts, is strongly urged upon.