Structure formation and the global 21-cm signal in the presence of Coulomb-like dark matter-baryon interactions
Structure formation and the global 21-cm signal in the presence of Coulomb-like dark matter-baryon interactions
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DOI：
10.1103/physrevd.106.103525
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发表时间：
2022-09
影响因子：
5
通讯作者：
Trey Driskell;E. Nadler;J. Mirocha;A. Benson;K. Boddy;T. Morton;J. Lashner;R. An;V. Gluscevic-V.
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文献类型：
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作者：
Trey Driskell;E. Nadler;J. Mirocha;A. Benson;K. Boddy;T. Morton;J. Lashner;R. An;V. Gluscevic-V.
许多引人注目的暗物质（DM）场景的特点是DM粒子和重子之间的库仑类相互作用，其中弹性散射截面与相对粒子速度成比例为$v^{-4}$。以前的研究已经调用这种相互作用来产生冷DM和重子之间的热交换，并改变氢的温度演化。在这项研究中，我们提出了一个全面的研究库仑散射的结构形成的影响，除了对氢的热历史的已知影响。我们发现，在宇宙黎明显着改变氢的温度的相互作用也显着抑制源的莱曼-$\alpha$背景的星系的形成，进一步影响全球21厘米的信号。特别是，在目前的观测上限的相互作用截面导致恒星形成晕的丰度减少的一个因素$\sim 2$在$z\sim 20$，相对于冷，无碰撞DM。我们还发现，DM是100%毫荷电不能再现的深度和时间的参数空间的任何部分中的报告的边缘异常。这些结果为DM重子散射宇宙学中全球21厘米信号和结构形成的建模提供了重要信息，并对未来和即将到来的宇宙学数据分析产生了影响。
Many compelling dark matter (DM) scenarios feature Coulomb-like interactions between DM particles and baryons, in which the cross section for elastic scattering scales with relative particle velocity as $v^{-4}$. Previous studies have invoked such interactions to produce heat exchange between cold DM and baryons and alter the temperature evolution of hydrogen. In this study, we present a comprehensive study of the effects of Coulomb-like scattering on structure formation, in addition to the known effects on the thermal history of hydrogen. We find that interactions which significantly alter the temperature of hydrogen at Cosmic Dawn also dramatically suppress the formation of galaxies that source the Lyman-$\alpha$ background, further affecting the global 21-cm signal. In particular, an interaction cross section at the current observational upper limit leads to a decrease in the abundance of star-forming halos by a factor of $\sim 2$ at $z\sim 20$, relative to cold, collisionless DM. We also find that DM that is 100% millicharged cannot reproduce the depth and the timing of the reported EDGES anomaly in any part of the parameter space. These results critically inform modeling of the global 21-cm signal and structure formation in cosmologies with DM-baryon scattering, with repercussions for future and upcoming cosmological data analysis.