The 21-cm signature of the first stars during the Lyman-Werner feedback era
The 21-cm signature of the first stars during the Lyman-Werner feedback era
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Lyman-Werner 反馈时代第一批恒星的 21 厘米签名
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
C. Hirata
中科院分区：
文献类型：
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作者：
A. Fialkov;R. Barkana;E. Visbal;Dmitriy Tseliakhovich;C. Hirata
第一批恒星的形成是天文学中一个令人兴奋的前沿领域。由于最近认识到暗物质和气体之间的超音速相对速度的影响，早期的红移(z∼20)在观测上很有希望。这一效应在100个共同移动的MPC尺度上产生了显著的结构，这使得探测从第一次加热时期开始的21厘米波动变得更加可行。我们首次使用半数值混合方法跟踪X射线和Lyman-Werner辐射背景的联合演化，包括超音速流动速度对恒星宇宙分布的影响。我们自洽地加入了莱曼-沃纳辐射对恒星形成的负反馈，莱曼-沃纳辐射解离了分子氢，从而抑制了气体冷却。我们发现，反馈延迟了Δz∼2的X射线加热相变，但在很大的红移范围内留下了有希望的大起伏信号。大尺度功率谱预计将在z∼18时达到最大信噪比，S/N∼3-4(对于投影的第一代仪器)，S/N>；1输出到z∼22-23。我们希望刺激更多的数值模拟以及专注于宇宙再电离之前的纪元的观测工作。
The formation of the first stars is an exciting frontier area in astronomy. Early redshifts (z ∼ 20) have become observationally promising as a result of a recently recognized effect of a supersonic relative velocity between the dark matter and gas. This effect produces prominent structure on 100 comoving Mpc scales, which makes it much more feasible to detect 21-cm fluctuations from the epoch of first heating. We use semi-numerical hybrid methods to follow for the first time the joint evolution of the X-ray and Lyman–Werner radiative backgrounds, including the effect of the supersonic streaming velocity on the cosmic distribution of stars. We incorporate self-consistently the negative feedback on star formation induced by the Lyman–Werner radiation, which dissociates molecular hydrogen and thus suppresses gas cooling. We find that the feedback delays the X-ray heating transition by Δz ∼ 2, but leaves a promisingly large fluctuation signal over a broad redshift range. The large-scale power spectrum is predicted to reach a maximal signal-to-noise ratio of S/N ∼ 3–4 at z ∼ 18 (for a projected first-generation instrument), with S/N >1 out to z ∼ 22–23. We hope to stimulate additional numerical simulations as well as observational efforts focused on the epoch prior to cosmic reionization.
影响因子：
8.7
作者：
Komatsu, E.;Smith, K. M.;Wright, E. L.
通讯作者：
Wright, E. L.