标题： 21厘米信号以及暗物质湮灭与天体物理过程之间的相互作用 显示英文标题

标题： The 21 cm signal and the interplay between dark matter annihilations and astrophysical processes

摘要： 未来专门的射电干涉仪，包括HERA和SKA，是非常有前景的工具，旨在通过中性氢的21厘米信号研究再电离时期及更早的时期。暗物质（DM）湮灭成带电粒子会改变宇宙的热历史，并因此影响21厘米信号。准确预测DM的影响强烈依赖于对晕中湮灭过程的建模。在这项工作中，我们使用了DM湮灭产物的能量沉积率的最新计算，对DM湮灭在晕中的贡献进行适当处理，以及由普朗克卫星最新的宇宙学测量所允许的湮灭截面值。鉴于当前对驱动再电离时期、X射线加热和Lyman-$\alpha$泵浦的天体物理过程描述存在不确定性，我们认为，将DM特征与纯粹的天体物理效应（与早期恒星形成过程或晚期星系X射线辐射相关）区分开来将是一个具有挑战性的任务。我们得出结论，只有质量为$\sim100$ MeV的DM粒子湮灭才可能在21厘米信号上留下明确的印记，特别是对21厘米功率谱而言。这与文献中以前更为乐观的结果形成对比，这些结果曾声称即使对于质量更高的DM，也可能存在强烈的特征。在不同宇宙时期的21厘米信号的额外测量对于打破DM湮灭与天体物理效应之间的强参数退化并无疑地识别出不同于$\sim100$ MeV的质量的DM印记将是至关重要的。 显示英文摘要

摘要： Future dedicated radio interferometers, including HERA and SKA, are very promising tools that aim to study the epoch of reionization and beyond via measurements of the 21 cm signal from neutral hydrogen. Dark matter (DM) annihilations into charged particles change the thermal history of the Universe and, as a consequence, affect the 21 cm signal. Accurately predicting the effect of DM strongly relies on the modeling of annihilations inside halos. In this work, we use up-to-date computations of the energy deposition rates by the products from DM annihilations, a proper treatment of the contribution from DM annihilations in halos, as well as values of the annihilation cross section allowed by the most recent cosmological measurements from the Planck satellite. Given current uncertainties on the description of the astrophysical processes driving the epochs of reionization, X-ray heating and Lyman-$\alpha$ pumping, we find that disentangling DM signatures from purely astrophysical effects, related to early-time star formation processes or late-time galaxy X-ray emissions, will be a challenging task. We conclude that only annihilations of DM particles with masses of $\sim100$ MeV, could leave an unambiguous imprint on the 21 cm signal and, in particular, on the 21 cm power spectrum. This is in contrast to previous, more optimistic results in the literature, which have claimed that strong signatures might also be present even for much higher DM masses. Additional measurements of the 21 cm signal at different cosmic epochs will be crucial in order to break the strong parameter degeneracies between DM annihilations and astrophysical effects and undoubtedly single out a DM imprint for masses different from $\sim100$ MeV.