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arXiv 0908.2428astro-ph.CO
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来自暗物质湮灭的河外gamma-ray background radiation

Extragalactic gamma-ray background radiation from dark matter annihilation

Jesus Zavala, Volker Springel, Michael Boylan-Kolchin

摘要:

如果暗物质是由中性伴子组成的,那么最令人兴奋的探测前景之一就是观测中性伴子对湮灭产生的伽马射线辐射,这一过程可能对河外伽马射线背景(EGB)辐射有重要贡献。在这里,我们使用高分辨率的千禧-II模拟宇宙结构的形成,以产生预期的辐射来自河外暗物质结构的第一个全天空地图。我们的地图制作过程中考虑到总的伽马射线光度从所有的晕和subhaloes,并包括未解决的组件的排放以及外推到中性伴子的阻尼尺度限制的校正。我们的分析还包括根据基于最小超引力的特定超对称模型对信号进行适当的归一化。利用新的模拟图可以研究暗物质湮灭产生的伽马射线背景的角功率谱,这种背景具有与湮灭过程的性质有关的独特特征,在最近发射的FERMI卫星即将进行的观测中可以探测到。我们的研究结果是在广泛的协议与分析模型的伽马射线背景,但它们也包括高阶相关性不容易在分析计算,此外,提供详细的光谱信息,每个像素。特别地,我们发现不同能量下的差分图可以揭示宇宙在低、中红移时的大尺度结构。如果本征发射光谱的特征在于发射峰,则具有伽马射线湮灭辐射的宇宙学层析成像在原则上是可能的。

英文摘要:

If dark matter is composed of neutralinos, one of the most exciting prospects for its detection lies in observations of the gamma-ray radiation created in pair annihilations between neutralinos, a process that may contribute significantly to the extragalactic gamma-ray background (EGB) radiation. We here use the high-resolution Millennium-II simulation of cosmic structure formation to produce the first full-sky maps of the expected radiation coming from extragalactic dark matter structures. Our map making procedure takes into account the total gamma-ray luminosity from all haloes and their subhaloes, and includes corrections for unresolved components of the emission as well as an extrapolation to the damping scale limit of neutralinos. Our analysis also includes a proper normalization of the signal according to a specific supersymmetric model based on minimal supergravity. The new simulated maps allow a study of the angular power spectrum of the gamma-ray background from dark matter annihilation, which has distinctive features associated with the nature of the annihilation process and may be detectable in forthcoming observations by the recently launched FERMI satellite. Our results are in broad agreement with analytic models for the gamma-ray background, but they also include higher-order correlations not readily accessible in analytic calculations and, in addition, provide detailed spectral information for each pixel. In particular, we find that difference maps at different energies can reveal cosmic large-scale structure at low and intermediate redshifts. If the intrinsic emission spectrum is characterized by an emission peak, cosmological tomography with gamma ray annihilation radiation is in principle possible.

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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