论文标题
高红移射电星系：21厘米波动的潜在新来源
High-redshift radio galaxies: a potential new source of 21-cm fluctuations
论文作者
论文摘要
预计无线电源将在高红移处形成，在低频下在宇宙微波背景（CMB）上方产生过量的辐射背景。通常会忽略它们对中性氢的红移21厘米信号的影响，因为假定相关背景很小。最近，已提出了高于CMB级别的无线电背景，这是对Edges协作报告的Redshift $ Z \ SIM 17 $的异常强21厘米信号的可能解释之一。结果，已经考虑了平稳且极强的无线电背景对天空平均（全局）21-CM信号及其波动的含义。在这里，我们考虑了由高红色星系人群创建的无线电背景的不均匀性，并表明它为密度，速度，ly-$ ly-$α$耦合，加热，加热和启用的众所周知的贡献增加了一种新型的21厘米波动。我们发现，即使具有适度增强的无线电效率（与边缘结果无关）的高红移星系也可能对X射线加热较弱的模型中的21-CM功率谱和全球信号产生重大影响。对于可以解释边缘数据的模型，我们进行了大型参数调查以探索其签名。我们表明，与仅CMB的标准情况相比，在$ z \ SIM 17 $处的21厘米功率谱可通过多达两个数量级增强，并且电源波动的形状和时间演变显着修饰。这些波动已接触到即将到来的无线电干涉仪。我们还发现，这些模型可以受到无线电源的当前和将来观察结果的显着限制。
Radio sources are expected to have formed at high redshifts, producing an excess radiation background above the cosmic microwave background (CMB) at low frequencies. Their effect on the redshifted 21-cm signal of neutral hydrogen is usually neglected, as it is assumed that the associated background is small. Recently, an excess radio background above the level of the CMB has been proposed as one of the possible explanations for the unusually strong 21-cm signal from redshift $z\sim 17$ reported by the EDGES collaboration. As a result, the implications of a smooth and extremely strong excess radio background on both the sky-averaged (global) 21-cm signal and its fluctuations have been considered. Here we take into account the inhomogeneity of the radio background created by a population of high-redshift galaxies, and show that it adds a new type of 21-cm fluctuations to the well-known contributions of density, velocity, Ly-$α$ coupling, heating and reionization. We find that a population of high-redshift galaxies even with a moderately-enhanced radio efficiency (unrelated to the EDGES result) can have a significant effect on the 21-cm power spectrum and global signal in models with weak X-ray heating. For models that can explain the EDGES data, we conduct a large parameter survey to explore their signatures. We show that in such models the 21-cm power spectrum at $z\sim 17$ is enhanced by up to two orders of magnitude compared to the CMB-only standard case, and the shape and time evolution of the power spectrum is significantly modified by the radio fluctuations. These fluctuations are within reach of upcoming radio interferometers. We also find that these models can be significantly constrained by current and future observations of radio sources.
