Near-infrared background anisotropies from diffuse intrahalo light of galaxies
Near-infrared background anisotropies from diffuse intrahalo light of galaxies
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DOI：
10.1038/nature11474
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发表时间：
2012-10-25
期刊：
影响因子：
64.8
通讯作者：
Wright, Edward L.
中科院分区：
文献类型：
--
作者：
Cooray, Asantha;Smidt, Joseph;Wright, Edward L.
宇宙近红外背景辐射的未解决的各向异性预计将来自最早的星系在再电离时期(1-5)和来自处于中等红移的微弱矮小星系(6，7)。以前的测量(8-12)无法确定主要的起源，因为它们没有抽样足够大的空间尺度来区分这两种可能性。本文报道了从亚角分到一度角尺度的各向异性功率谱的测量结果，发现团簇的幅度比基于现有两种解释的模型所预测的要大。由于功率谱的散粒噪声水平与来自暗星系的预期水平一致，因此没有必要在天空上建立新的源群体来解释观测结果。然而，需要一种增加聚集幅度的物理机制。受到最近关于暗物质晕(13-15)中扩展的恒星光轮廓的相关结果的启发，我们考虑了这种涨落来自所有星系的晕内星的可能性。我们发现，测量到的功率谱可以用红移约1到4的10(9)到10(12)个太阳质量的暗物质晕中0.07%到0.2%的晕内光分量来解释。
Unresolved anisotropies of the cosmic near-infrared background radiation are expected to have contributions from the earliest galaxies during the epoch of reionization(1-5) and from faint, dwarf galaxies at intermediate redshifts(6,7). Previous measurements(8-12) were unable to pinpoint conclusively the dominant origin because they did not sample spatial scales that were sufficiently large to distinguish between these two possibilities. Here we report a measurement of the anisotropy power spectrum from subarcminute to one-degree angular scales, and find the clustering amplitude to be larger than predicted by the models based on the two existing explanations. As the shot-noise level of the power spectrum is consistent with that expected from faint galaxies, a new source population on the sky is not necessary to explain the observations. However, a physical mechanism that increases the clustering amplitude is needed. Motivated by recent results related to the extended stellar light profile in dark-matter haloes(13-15), we consider the possibility that the fluctuations originate from intrahalo stars of all galaxies. We find that the measured power spectrum can be explained by an intrahalo light fraction of 0.07 to 0.2 per cent relative to the total luminosity in dark-matter haloes of 10(9) to 10(12) solar masses at redshifts of about 1 to 4.