Cosmological free-free emission from dark matter halos in the ΛCDM model
Cosmological free-free emission from dark matter halos in the ΛCDM model
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ΛCDM 模型中暗物质晕的宇宙学自由发射
DOI：
10.1103/physrevd.106.063523
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发表时间：
2022
影响因子：
5
通讯作者：
Tashiro Hiroyuki
中科院分区：
文献类型：
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作者：
Abe Katsuya T.;Tashiro Hiroyuki
我们研究了暗物质晕引起的漫反射背景自由辐射。由于暗物质晕拥有电离的热等离子体，它们可能是宇宙学自由辐射的重要来源。我们将评估这种自由-自由发射的全球背景强度和各向异性。我们发现，主要贡献来自暗物质晕，其质量接近Jeans质量，在红移附近。因此，自由-自由发射的强度对形成这种小质量暗物质晕的小尺度原始曲率微扰很敏感。尽管我们得到的全球和各向异性自由-自由发射的强度小于在高星系区观测到的自由-自由发射的10%水平，但我们发现自由-自由发射信号在光谱指数和运行参数集内被修正，这与最近的普朗克结果是一致的。因此，对宇宙自由信号的测量有可能对小质量暗物质晕的丰度和曲率扰动(包括光谱指数和运行)提供更严格的约束，同时需要通过多频射电观测或与星系测量或21厘米强度图的相互关联研究来仔细消除银河系的自由发射。
We study the diffuse background free-free emission induced by dark matter halos. Since dark matter halos host ionized thermal plasma, they could be an essential source of cosmological free-free emission. We evaluate the global background intensity and the anisotropy of this free-free emission. We show that the dominant contribution comes from dark matter halos with a mass close to the Jeans mass,, around the redshift. Therefore, the intensity of the free-free emission is sensitive to the small-scale primordial curvature perturbations that form such small-mass dark matter halos. Although our obtained intensity of the global and anisotropic free-free emission is smaller than the 10% level of the free-free emission observed in the high galactic region, we find that the free-free emission signal is modified byeven in the parameter set of the spectral index and the running, which is consistent with the recent Planck result. Therefore, the measurement of the cosmological free-free signals has the potential to provide more stringent constraints on the abundance of small-mass dark matter halos and the curvature perturbations including the spectral index and the running, while carefully removing the Galactic free-free emission is required through the multifrequency radio observation or the cross-correlation study with the galaxy surveys or 21-cm intensity map.