The near-infrared background (NIRB) is one of a few methods that can be used to observe the redshifted light from early stars at a redshift of 6 and above, and thus it is imperative to understand the significance of any detection or nondetection of the NIRB. Fluctuations of the NIRB can provide information on the first structures, such as halos and their surrounding ionized regions in the intergalactic medium (IGM). We combine, for the first time, N-body simulations, radiative transfer code, and analytic calculations of luminosity of early structures to predict the angular power spectrum (Cl ) of fluctuations in the NIRB. We study in detail the effects of various assumptions about the stellar mass, the initial mass spectrum of stars, the metallicity, the star formation efficiency (f *), the escape fraction of ionizing photons (f esc), and the star formation timescale (t SF), on the amplitude as well as the shape of Cl . The power spectrum of NIRB fluctuations is maximized when f * is the largest (as Cl ∝ f 2 *) and f esc is the smallest (as more nebular emission is produced within halos). A significant uncertainty in the predicted amplitude of Cl exists due to our lack of knowledge of t SF of these early populations of galaxies, which is equivalent to our lack of knowledge of the mass-to-light ratio of these sources. We do not see a turnover in the NIRB angular power spectrum of the halo contribution, which was claimed to exist in the literature, and explain this as the effect of high levels of nonlinear bias that was ignored in the previous calculations. This is partly due to our choice of the minimum mass of halos contributing to NIRB (~2 × 109 M ☉), and a smaller minimum mass, which has a smaller nonlinear bias, may still exhibit a turnover. Therefore, our results suggest that both the amplitude and shape of the NIRB power spectrum provide important information regarding the nature of sources contributing to the cosmic reionization. The angular power spectrum of the IGM, in most cases, is much smaller than the halo angular power spectrum, except when f esc is close to unity, t SF is longer, or the minimum redshift at which the star formation is occurring is high. In addition, low levels of the observed mean background intensity tend to rule out high values of f * 0.2.
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机译：近红外背景（NIRB）是可用于观察6或更高红移的早期恒星的红移光的几种方法之一，因此必须了解任何检测或未检测到该红光的重要性。 NIRB。 NIRB的波动可提供有关第一结构的信息，例如银河系之间的光晕及其周围的离子化区域（IGM）。我们首次结合N体模拟，辐射传递代码和早期结构的光度解析计算来预测NIRB波动的角功率谱（Cl）。我们详细研究了关于恒星质量，恒星的初始质谱，金属性，恒星形成效率（f *），电离光子的逸出率（f esc）和恒星形成时标（ t SF），以及Cl的幅度和形状。当f *最大时（如Cl ∝ f 2 *），而f esc最小时（由于晕圈中产生更多的星云发射），NIRB波动的功率谱最大化。由于我们缺乏对这些早期星系种群的t SF的认识，因此Cl的预测振幅存在很大的不确定性，这相当于我们对这些来源的质光比缺乏了解。我们没有在光晕贡献的NIRB角功率谱中看到翻转，这在文献中声称存在，并将其解释为在先前的计算中被忽略的高水平非线性偏置的影响。这部分是由于我们选择了有助于NIRB的最小光晕质量（〜2×109 M☉），较小的最小质量（具有较小的非线性偏差）可能仍会产生周转。因此，我们的结果表明，NIRB功率谱的幅度和形状都提供了有关有助于宇宙离子化的源的性质的重要信息。在大多数情况下，IGES的角功率谱比光晕角功率谱小得多，除非当f esc接近于1时，t SF更长，或者发生恒星形成的最小红移很高。此外，观察到的平均背景强度低会趋于排除f * 0.2的高值。
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