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arXiv 2206.04075astro-ph.HE
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高于100 GeV的各向同性$γ$射线发射:非常高能量的$γ$射线来自哪里?

The isotropic $γ$-ray emission above 100 GeV: where do very high energy $γ$ rays come from?

Raniere de Menezes, Raffaele D'Abrusco, Francesco Massaro, Sara Buson

摘要:

天体物理学中极高能量(VHE; $>100$ GeV)的$γ$射线源是罕见的,因为GeV和TeV的光子只能在相对论粒子与局部辐射和磁场相互作用的极端情况下发射。在费米大面积望远镜(LAT)的背景下,只有少数来源是已知的VHE发射源,其中最大的部分属于最稀有的活动星系核:耀变体。在这项工作中,我们探索费米LAT数据的能量$>100$ GeV和银河系纬度$b > |50^{\circ}|$,以探测河外各向同性$γ$射线发射的起源。由于这种VHE光子的产生需要非常特殊的天体物理条件,我们预计来自各向同性$γ$射线发射的大多数VHE光子来自耀变体或其他极端物体,如恒星形成星系,$γ$射线爆发和射电星系,在银河系的纬度上探测到一个VHE光子就足以明确地追踪到这样一个对应物的存在。我们的研究结果表明,耀变体是,到目前为止,占主导地位的类源100 GeV以上,虽然他们只占$22.8^{+4.5}_{-4.1}\%$的河外VHE光子。VHE光子的剩余$77^{+4.1}_{-4.5}\%$仍然具有未知的来源。

英文摘要:

Astrophysical sources of very high energy (VHE; $>100$ GeV) $γ$ rays are rare, since GeV and TeV photons can be only emitted in extreme circumstances involving interactions of relativistic particles with local radiation and magnetic fields. In the context of the Fermi Large Area Telescope (LAT), only a few sources are known to be VHE emitters, where the largest fraction belongs to the rarest class of active galactic nuclei: the blazars. In this work, we explore Fermi-LAT data for energies $>100$ GeV and Galactic latitudes $b > |50^{\circ}|$ in order to probe the origin of the extragalactic isotropic $γ$-ray emission. Since the production of such VHE photons requires very specific astrophysical conditions, we would expect that the majority of the VHE photons from the isotropic $γ$-ray emission originate from blazars or other extreme objects like star-forming galaxies, $γ$-ray bursts, and radio galaxies, and that the detection of a single VHE photon at the adopted Galactic latitudes would be enough to unambiguously trace the presence of such a counterpart. Our results suggest that blazars are, by far, the dominant class of source above 100 GeV, although they account for only $22.8^{+4.5}_{-4.1}\%$ of the extragalactic VHE photons. The remaining $77^{+4.1}_{-4.5}\%$ of the VHE photons still have an unknown origin.

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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