Contribution from star-forming galaxies to the cosmic gamma-ray background radiation
Contribution from star-forming galaxies to the cosmic gamma-ray background radiation
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DOI：
10.1088/0004-637x/728/2/158
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发表时间：
2010-05
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影响因子：
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通讯作者：
R. Makiya
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文献类型：
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作者：
R. Makiya
星系外伽马射线本底(EGRB)的起源一直是人们讨论的焦点，各种源可能对其有贡献，如活动星系核、恒星形成星系、星系团、结构形成和暗物质湮灭等。我们提出了一种新的理论计算恒星形成星系对EGRB的贡献，其基础是一个最先进的星系形成模型，该模型与对当地星系的各种观测以及高红移都是定量一致的。利用附近星系的最新观测数据，星系的伽马射线光度和光谱与恒星形成率、气体质量和模型星系的恒星形成模式(静止或恒星爆发)有关。我们的标准模型预测，来自恒星形成星系的∼占最近费米伽马射线太空望远镜报告的总EGRB流量的14%。费米探测到的附近星系的预测数量与观测结果一致。活动星系核和恒星形成星系的已知贡献之和可以解释EGRB的很大一部分，预测的模型光谱与观测结果惊人地吻合。
The origin of extragalactic gamma-ray background (EGRB) has been discussed for a long time and various sources have been discussed as possible contributors to EGRB, such as active galactic nuclei, star-forming galaxies, galaxy clusters, structure formation, and dark matter annihilation. We present a new theoretical calculation of the contribution to the EGRB from star-forming galaxies based on a state-of-the-art model of hierarchical galaxy formation that is in quantitative agreement with a variety of observations of local galaxies as well as high redshifts. Gamma-ray luminosity and spectrum of galaxies are related to star formation rate, gas mass, and star formation mode (quiescent or starburst) of model galaxies using latest observed data of nearby galaxies. Our standard model predicts ∼ 14% contribution from star-forming galaxies to the total EGRB flux recently reported by the Fermi Gamma-Ray Space Telescope. The predicted number of nearby galaxies detectable by Fermi is consistent with the observation. The sum of the known contributions from AGNs and star-forming galaxies can explain a large part of EGRB, with a remarkable agreement between the predicted model spectrum and observation.