重建皮埃尔·奥格天文台的超高能宇宙射线偶极：4LAC活动星系核与近邻星暴星系的混合分析
Reconstructing the Auger UHECR Dipole: A Hybrid Analysis of 4LAC AGNs and Nearby Starburst Galaxies
AI总结：
本研究针对奥格天文台观测的UHECR偶极，构建AGN+SBG混合模型，发现单独的AGN或SBG无法解释该偶极，混合模型在8-16 EeV能区拟合良好，且其他能区SBG贡献占比逐渐提升。
AI中文摘要：
皮埃尔·奥格天文台观测到的8 EeV以上的大尺度偶极各向异性，为超高能宇宙射线（UHECR）的起源提供了重要线索。本研究探讨来自费米-LAT第四AGN目录（4LAC）的伽马射线活动星系核（AGN）是否能解释观测到的偶极，并检验近邻星暴星系（SBG）的贡献。结合源流量、红移分布、GZK衰减和混合成分框架，研究表明单独的AGN或SBG单源群体无法重现观测到的奥格偶极。为解决该问题，构建了AGN+SBG混合模型。在8-16 EeV能区，最佳拟合解要求AGN贡献为23%、SBG贡献为45%，得到的偶极振幅为5.03%，同时保持偶极方向为（104.1°，-25.1°），角分离为7.10°。在其他能区，近邻SBG在各向异性分量中的占比逐渐增大，而AGN则与准各向同性背景共同提供次要贡献。
英文摘要：
The large-scale dipole anisotropy observed by the Pierre Auger Observatory above $8$~EeV provides important clues about the origin of ultra-high-energy cosmic rays (UHECRs). In this work, we investigate whether gamma-ray active galactic nuclei (AGNs) from the Fermi-LAT Fourth AGN Catalog (4LAC) can explain the observed dipole and examine the contribution of nearby starburst galaxies (SBGs). Incorporating source fluxes, redshift distributions, GZK attenuation, and a mixed-composition framework, we demonstrate that single-source populations of AGNs and SBGs alone fail to reproduce the observed Auger dipole. To resolve this, we construct a hybrid AGN+SBG model. The best-fit solution for the $8$--$16$~EeV interval requires a $23$\% AGN contribution and $45$\% SBG contribution, which gives a dipole amplitude of $5.03$\% while maintaining the dipole direction of ($104.1^\circ$, $-25.1^\circ$) with angular separation of $7.10^\circ$. In the other energy intervals also, we find that the nearby SBGs increasingly dominate the anisotropic component while AGNs provide a subdominant contribution alongside a quasi-isotropic background.
