Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA.
Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel.
Phys Rev Lett. 2018 Jul 6;121(1):011101. doi: 10.1103/PhysRevLett.121.011101.
The recent detection of an anomalously strong 21-cm signal of neutral hydrogen from cosmic dawn by the EDGES low-band radio experiment can be explained if cold dark matter particles scattered off the baryons draining excess energy from the gas. In this Letter we explore the expanded range of the 21-cm signal that is opened up by this interaction, varying the astrophysical parameters as well as the properties of dark matter particles in the widest possible range. We identify models consistent with current data by comparing to both the detection in the low-band region and the upper limits from the EDGES high-band antenna. We find that consistent models predict a 21-cm fluctuation during cosmic dawn that is between 3 and 30 times larger than the largest previously expected without dark matter scattering. The expected power spectrum exhibits strong baryon acoustic oscillations imprinted by the velocity-dependent cross section. The latter signature is a conclusive evidence of the velocity-dependent scattering and could be used by interferometers to verify the dark matter explanation of the EDGES detection.
EDGES 低波段射电实验最近探测到宇宙黎明时期中性氢的异常强的 21cm 信号，如果冷暗物质粒子与从气体中抽取多余能量的重子发生散射，就可以解释这一现象。在这封信中，我们通过改变天体物理参数以及尽可能广泛的暗物质粒子性质，探索了这种相互作用所开辟的 21cm 信号的扩展范围。我们通过与低波段区域的探测以及 EDGES 高波段天线的上限进行比较，确定了与当前数据一致的模型。我们发现，一致的模型预测宇宙黎明时期的 21cm 涨落比没有暗物质散射时之前预期的最大涨落大 3 到 30 倍。预期的功率谱显示出由速度相关的横截面产生的强烈的重子声学振荡印记。后一特征是速度相关散射的决定性证据，干涉仪可以用它来验证 EDGES 探测的暗物质解释。
