Cross-correlations between 21 cm,X-ray and infrared backgrounds

作     者：Huan-Yuan Shan Bo Qin 

作者机构：National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China 

出 版 物：《Chinese Journal of Astronomy and Astrophysics》 (中国天文和天体物理学报（英文版）)

年 卷 期：2009年第9卷第1期

页      面：73-84页

核心收录：

学科分类：07[理学] 0704[理学-天文学] 

基　　金：supported by a CAS grant KJCX3-SYW-N2.References 

主　　题：cosmology theory - X-rays diffuse background -infrared stars 

摘      要：The history of the cosmological reionization is still unclear. Two ionizing sources, stars and QSOs, are believed to play important roles during this epoch. Besides the 21 cm signals, the infrared emission from PopⅢ stars and X-ray photons from QSOs can be powerful probes of the reionization. Here we present a cross-correlation study of the 21 cm, infrared and X-ray backgrounds. The advantage of doing such crosscorrelations is that we could highlight the correlated signals and eliminate irrelevant foregrounds. We develop a shell model to describe the 21 cm signals and find that PopIII stars can provide higher 21 cm signals than QSOs. Using the ROSAT data for X-ray and AKARI data for infrared, we predict various cross power spectra analytically and discuss prospects for detecting these cross-correlation signals in future low frequency radio surveys. We find that, although these cross-correlational signals have distinct features, so far, they have been difficult to detect due to the high noise of the soft X-ray and infrared backgrounds given by ROSAT and AKARI.