arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2003.05493astro-ph.GAastro-ph.COastro-ph.HE
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成星星系的$γ$射线辐射

The $γ$-ray Emission of Star-Forming Galaxies

M. Ajello, M. Di Mauro, V. S. Paliya, S. Garrappa

摘要:

恒星形成星系的大部分$γ$射线辐射是由高能宇宙射线与星际气体和辐射场相互作用产生的。恒星形成的星系被认为对河外$γ$射线背景和冰立方天体物理中微子通量都有贡献。利用{ \it Fermi}大天区望远镜大约10\,年的$γ$射线数据,我们对恒星形成星系的$γ$射线性质进行了约束。我们报告了11个真正的$γ$射线发射星系和2个候选星系的探测结果。此外,我们还发现,在$\sim$ 5\,$σ$置信度下,也能显著地探测到阈下星系的累积$γ$射线辐射。发现分辨和未分辨星系的$γ$射线光度与先前测定的总(8-1000 μ m,$μ$ m)红外光度相关。在1,GeV以上,已分辨星系和未分辨星系的光谱能量分布符合光子指数为$\approx2.2-2.3$的幂律.最后,我们发现恒星形成星系分别占河外$γ$射线背景和冰立方中微子通量的大约5%和3%。

英文摘要:

A majority of the $γ$-ray emission from star-forming galaxies is generated by the interaction of high-energy cosmic rays with the interstellar gas and radiation fields. Star-forming galaxies are expected to contribute to both the extragalactic $γ$-ray background and the IceCube astrophysical neutrino flux. Using roughly 10\,years of $γ$-ray data taken by the {\it Fermi} Large Area Telescope, in this study we constrain the $γ$-ray properties of star-forming galaxies. We report the detection of 11 bona-fide $γ$-ray emitting galaxies and 2 candidates. Moreover, we show that the cumulative $γ$-ray emission of below-threshold galaxies is also significantly detected at $\sim$5\,$σ$ confidence. The $γ$-ray luminosity of resolved and unresolved galaxies is found to correlate with the total (8-1000\,$μ$m) infrared luminosity as previously determined. Above 1\,GeV, the spectral energy distribution of resolved and unresolved galaxies is found to be compatible with a power law with a photon index of $\approx2.2-2.3$. Finally, we find that star-forming galaxies account for roughly 5\,\% and 3\,\% of the extragalactic $γ$-ray background and the IceCube neutrino flux, respectively.

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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