与高质量重建高能中微子事件相关联的耀变体的轻子-强子模型研究

中文摘要 AI 辅助

活动星系核（AGN）与高能中微子的关联已通过种群和单个源分析进行研究，但这些关联反映的是物理过程还是偶然巧合仍无定论。耀变体是一类相对论性喷流与视线方向对齐的AGN，其空间位置与IceCube高能事件相符，为解答这一问题提供了自然框架。将多频观测与物理动机明确的发射模型相结合，可以评估这些源是否能够合理地解释所探测到的中微子。我们研究了六个与高质量重建的IceCAT-1高能事件具有单一伽马射线对应体的耀变体，并考虑了IceCAT-2预期带来的定位改进，汇编了它们的多频光谱能量分布（SEDs）。我们在轻子-强子框架内对这些源进行建模，探索其参数空间以重现观测到的发射，同时优先选择能最大化中微子产生的解。SEDs可以用靠近宽线区的紧凑发射区域和中等多普勒因子来重现。发射通常以轻子为主，强子级联贡献次之，但有一个源的伽马射线以强子为主。对于其中四个源，相对论性粒子的能量密度接近与磁场的等分。预测的中微子探测率高达每年约5×10⁻²，在泊松统计下与观测到的一个IceCube事件基本兼容。虽然这些耀变体不太可能显著贡献弥散中微子通量，但它们的性质与作为单个中微子事件的可能对应体一致，这得益于外部光子场对强子相互作用率的贡献，即使对于这些场先前被认为不显著的源也是如此。

英文摘要

The association of active galactic nuclei (AGN) with high-energy neutrinos has been studied through population and individual source analyzes, but whether these associations reflect physical processes or chance coincidences remains open. Blazars, AGN with relativistic jets aligned with the line of sight, spatially consistent with IceCube high-energy events, offer a natural framework to address this question. Combining multifrequency observations with physically motivated emission models allows us to assess whether these sources can plausibly account for the detected neutrinos. We study six blazars with single gamma-ray counterparts to well-reconstructed IceCAT-1 high-energy events, accounting for the improved localization expected from IceCAT-2, and compile their multifrequency spectral energy distributions (SEDs). We model these sources within a lepto-hadronic framework, exploring their parameter space to reproduce the observed emission while favoring solutions that maximize neutrino production. The SEDs can be reproduced with compact emission regions close to the broad-line region with moderate Doppler factors. The emission is generally leptonic-dominated, with subdominant contributions from hadronic cascades, except for one source where the gamma-rays are hadronic-dominated. For four, the energy density of the relativistic particles is close to equipartition with the magnetic field. The predicted neutrino detection rates reach up to $~5x10^{-2}$ per year, mostly compatible with one observed IceCube event under Poisson statistics. While these blazars are unlikely to significantly contribute to the diffuse neutrino flux, their properties are consistent with being possible counterparts to individual neutrino events, driven by contributions of external photon fields to the hadronic interaction rate, even for sources where these fields have previously been considered as non-significant.

发表机构

• Julius-Maximilians-Universität Würzburg（维尔茨堡朱利叶斯-马克西米利安大学）
• Deutsches Elektronen-Synchrotron DESY（德国电子同步加速器）
• Weizmann Institute of Science（魏兹曼科学研究所）

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