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arXiv 1602.03512astro-ph.CO
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河外背景光的测量与应用

Extragalactic Background Light: Measurements and Applications

Asantha Cooray

摘要:

本文综述了在20多个波段的电磁波谱中从γ射线到射电的河外背景光强度的测量。宇宙微波背景(CMB)仍然是最好的测量光谱,精度优于1%。与宇宙光学背景(COB)有关的测量,中心在1微米处,受到与太阳系内部行星际尘埃相关的大黄道光的影响。对COB的最佳测量来自一种间接技术,该技术涉及明亮耀变体的伽马射线光谱,其吸收特征来自COB光子的成对产生。宇宙红外背景(CIB)在100微米左右达到峰值,建立了一个能量重要的背景,其强度与光学背景相当。这一发现为大口径远红外和亚毫米观测铺平了道路,从而发现了尘埃,星爆星系。它们在星系形成和演化中的作用仍然是现代天体物理学研究的一个活跃领域。极端紫外背景仍然是大多未被探索,将是一个挑战,以测量由于高银河系背景和吸收河外光子的星系际介质在这些EUV/软X射线能量。我们还总结了我们的理解的空间各向异性和角功率谱的强度起伏。我们激励一个精确的直接测量的COB之间的0.1至5微米,使用小口径望远镜观察无论是从外太阳系,在5 AU或更大的距离,或出黄道平面。其他未来的应用包括提高我们的理解,在TeV的能量和光谱的CMB和CIB的扭曲的背景。

英文摘要:

This review covers the measurements related to the extragalactic background light (EBL) intensity from gamma-rays to radio in the electromagnetic spectrum over 20 decades in the wavelength. The cosmic microwave background (CMB) remains the best measured spectrum with an accuracy better than 1%. The measurements related to the cosmic optical background (COB), centered at 1 microns, are impacted by the large zodiacal light associated with interplanetary dust in the inner Solar system. The best measurements of COB come from an indirect technique involving Gamma-ray spectra of bright blazars with an absorption feature resulting from pair-production off of COB photons. The cosmic infrared background (CIB) peaking at around 100 microns established an energetically important background with an intensity comparable to the optical background. This discovery paved the path for large aperture far-infrared and sub-millimeter observations resulting in the discovery of dusty, starbursting galaxies. Their role in galaxy formation and evolution remains an active area of research in modern-day astrophysics. The extreme UV background remains mostly unexplored and will be a challenge to measure due to the high Galactic background and absorption of extragalactic photons by the intergalactic medium at these EUV/soft X-ray energies. We also summarize our understanding of the spatial anisotropies and angular power spectra of intensity fluctuations. We motivate a precise direct measurement of the COB between 0.1 to 5 microns using a small aperture telescope observing either from the outer Solar system, at distances of 5 AU or more, or out of the ecliptic plane. Other future applications include improving our understanding of the background at TeV energies and spectral distortions of CMB and CIB.

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。

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