CMB光谱中的预重组能量释放和窄特征
Pre-recombinational energy release and narrow features in the CMB spectrum
摘要：
早期宇宙（z<~ 2x10^6）的能量释放应该会导致宇宙微波背景（CMB）辐射场的某些宽谱畸变，当注入过程开始于红移z<~ 5x10^4时，这种畸变可以被表征为y型畸变。在这里，我们证明，如果能量被释放之前宇宙学的氢复合开始（z~1400），在HI和HeII的束缚束缚和自由束缚跃迁的闭环导致（i）的外观特征的多个窄光谱特征在dm和cm波长，和（ii）一个突出的亚毫米波的CMB光谱的远维恩尾的吸收和发射部分组成。额外的光谱特征产生于HI（z>~1800）和HeII（z>~7000）的重组前时期，因此不同于在未受干扰的CMB黑体辐射场中由于正常宇宙学重组而产生的光谱特征。我们给出了包括25个原子壳层的HI和HeII的数值计算结果，并详细讨论了几个单独的跃迁的贡献。作为例子，我们考虑的情况下，瞬时能量释放（例如，由于相变）和指数能量释放，因为长寿命的衰变粒子。我们的计算表明，由于可能的预重组原子跃迁的CMB光谱失真的可变性增加时，与正常的重组时期产生的失真。这些窄光谱特征的存在将为分离由于重组前（1400 <~ z <~5x10^4）能量释放而导致的y畸变和在红移z<~800的重组后产生的y畸变开辟一条独特的途径。（节略）
英文摘要：
Energy release in the early Universe (z<~ 2x10^6) should lead to some broad spectral distortion of the cosmic microwave background (CMB) radiation field, which can be characterized as y-type distortion when the injection process started at redshifts z<~ 5x10^4. Here we demonstrate that if energy was released before the beginning of cosmological hydrogen recombination (z~1400), closed loops of bound-bound and free-bound transitions in HI and HeII lead to the appearance of (i) characteristic multiple narrow spectral features at dm and cm wavelengths, and (ii) a prominent sub-millimeter feature consisting of absorption and emission parts in the far Wien tail of CMB spectrum. The additional spectral features are generated in the pre-recombinational epoch of HI (z>~1800) and HeII (z>~7000), and therefore differ from those arising due to normal cosmological recombination in the undisturbed CMB blackbody radiation field. We present the results of numerical computations including 25 atomic shells for both HI and HeII, and discuss the contributions of several individual transitions in detail. As examples, we consider the case of instantaneous energy release (e.g. due to phase transitions) and exponential energy release because of long-lived decaying particles. Our computations show that due to possible pre-recombinational atomic transitions the variability of the CMB spectral distortion increases when comparing with the distortions arising in the normal recombination epoch. The existence of these narrow spectral features would open an unique way to separate y-distortions due to pre-recombinational ($1400<~ z <~5x10^4) energy release from those arising in the post-recombinational era at redshifts z<~800. (abridged)
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
