An issue currently under debate in the literature is how far from the black hole is the Fermi-observed GeV emission of powerful blazars emitted. Here we present a clear diagnostic tool for testing whether the GeV emission site is located within the sub-pc broad emission line (BLR) region or further out in the few pc scale molecular torus (MT) environment. Within the BLR the scattering takes place at the onset of the Klein-Nishina regime, causing the electron cooling time to become almost energy independent and as a result, the variation of high-energy emission is expected to be achromatic. Contrarily, if the emission site is located outside the BLR, the expected GeV variability is energy-dependent and with amplitude increasing with energy. We demonstrate this using time-dependent numerical simulations of blazar variability.
Energy-Dependent Polarization Angle Variability as a Robust Diagnostic for Blazar Flaring Mechanisms
University of Maryland Baltimore County（马里兰大学巴尔的摩县分校）；NASA Goddard Space Flight Center（美国国家航空航天局戈达德太空飞行中心）；Washington University in St Louis（华盛顿大学圣路易斯分校）；Los Alamos National Lab（洛斯阿拉莫斯国家实验室）；New Mexico Consortium（新墨西哥联盟）
Exploring the Transitional Parameter Space of Blazars using Gamma-ray and X-ray Population Diagnostics
本文通过第四次费米LAT源目录数据释放4（4FGL-DR4）和Living Swift XRT点源目录中的X射线信息，研究了变光BL Lac对象（CLBs）的伽马射线和X射线群体特性，发现CLBs在伽马射线参数空间中主要位于BLL和FSRQ群体的中间和重叠区域，但在不同参数平面上的质心位置以及PCA和UMAP投影显示CLBs更接近FSRQ区域，X射线分析也显示CLBs在X射线参数空间中更接近FSRQs而非BLLs，且X射线/伽马射线耦合关系和随机森林分类概率与这一趋势一致。
Quasi-Simultaneous Broadband Spectral Energy Distributions of a Sample of Fermi Blazars -- I. Correlation Results
Zhejiang Normal University（浙江师范大学）；Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）；University of Science and Technology of China（中国科学技术大学）；Shanghai Normal University（上海师范大学）；Yunnan Observatories, Chinese Academy of Sciences（中国科学院云南天文台）；Center for Astronomical Mega-Science, Chinese Academy of Sciences（中国科学院国家天文台）；College of Physics and Electronic Engineering, Qilu Normal University（齐鲁师范学院物理与电子工程学院）
Correlation Between Hard X-Ray and Cosmic Neutrino Sources: From Obscured AGN to Blazars
ELTE Eötvös Loránd University（厄特沃什·罗兰大学）；HUN-REN Research Centre for Astronomy and Earth Sciences（匈牙利研究与教育网络地球科学与天文学研究中心）；Ruhr University Bochum（波鸿鲁尔大学）；University of Florida（佛罗里达大学）；University of Geneva（日内瓦大学）；Universidad Diego Portales（迭戈·波特莱斯大学）；Chalmers University of Technology（查尔姆斯理工大学）；University of Wisconsin, Madison（威斯康星大学麦迪逊分校）
