Lower bounds are derived on the amplitude B of intergalactic magnetic fields (IGMFs) in the region between Galaxy and the blazar Mrk 421, from constraints on the delayed GeV pair-echo flux that are emitted by secondary e^-e^+ produced in γγinteractions between primary TeV gamma-rays and the cosmic infrared background. The distribution of galaxies mapped by the Sloan Digital Sky Survey shows that this region is dominated by a large intergalactic void. We utilize data from long-term, simultaneous GeV-TeV observations by the Fermi Large Area Telescope and the ARGO-YBJ experiment extending over 850 days. For an assumed value of B, we evaluate the daily GeV pair-echo flux expected from the TeV data, select the dates where this exceeds the Fermi 2-σsensitivity, compute the probability that this flux is excluded by the Fermi data for each date, and then combine the probabilities using the inverse normal method. Consequently, we exclude B < 10^{-20.5} G for a field coherence length of 1 kpc at 4- σlevel, as long as plasma instabilities are unimportant for cooling of the pair beam. This is much more significant than the 2-σbounds we obtained previously from observations of Mrk 501, by virtue of more extensive data from the ARGO-YBJ, as well as improved statistical analysis. Compared with most other studies of IGMF bounds, the evidence we present here for a non-zero IGMF is more robust as it does not rely on unproven assumptions on the primary TeV emission during unobserved periods.
Constraints on the intergalactic magnetic field from Fermi-LAT observations of GRB 221009A
University of Hamburg（汉堡大学）；Kirchhoff-Institute for Physics, Heidelberg University（海德堡大学基尔霍夫物理研究所）；INAF – Osservatorio di Astrofisica e Scienza dello Spazio di Bologna（博洛尼亚天文物理与空间科学国家研究所）；Universitá di Trieste（的里雅斯特大学）；Istituto Nazionale di Fisica Nucleare, Sezione di Trieste（意大利国家核物理研究所的里雅斯特分部）
通过GRB 221009A的观测，研究利用费米- LAT数据对星际磁场进行限制，得出B < 2.5 x 10^{-17} G的约束。
Turbulent Transport of Galactic Magnetic Fields into Cosmic Voids: Insights from IllustrisTNG
Graduate School of Science, Nagoya University（名古屋大学大学院理学研究科）；Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University（名古屋大学小林-益川粒子宇宙起源研究所）；Institute for Advanced Research, Nagoya University（名古屋大学高等研究院）
Pair echo model of CTAO/LST-1 signal from GRB 221009A
Université Paris Cité（巴黎西岱大学）；CNRS, Astroparticule et Cosmologie（法国国家科学研究中心，亚原子粒子与宇宙学）；Laboratory of Astrophysics, École Polytechnique Fédérale de Lausanne（洛桑联邦理工学院天体物理学实验室）；Institute for Cosmic Ray Research, The University of Tokyo（东京大学宇宙射线研究所）；Université Paris-Saclay（巴黎萨克雷大学）；CEA, CNRS, AIM（法国原子能委员会，法国国家科学研究中心，天体物理学与分子生物学研究所）；Gran Sasso Science Institute（格兰萨索科学研究所）；Istituto Nazionale di Fisica Nucleare (INFN), Sez. Padova（意大利国家核物理研究所，帕多瓦分部）；INAF - Osservatorio Astronomico di Brera（意大利国家天体物理研究所，布雷拉天文台）
Magnetic field spreading from stellar and galactic dynamos into the exterior
Nordita, KTH Royal Institute of Technology and Stockholm University（诺迪塔，皇家理工学院和斯德哥尔摩大学）；The Oskar Klein Centre, Department of Astronomy, Stockholm University（奥斯卡·克莱因中心，天文学系，斯德哥尔摩大学）；McWilliams Center for Cosmology & Department of Physics, Carnegie Mellon University（麦克威廉斯宇宙学中心与物理系，卡内基梅隆大学）；School of Natural Sciences and Medicine, Ilia State University（自然科学与医学院，伊利亚州立大学）；Oskar Klein Centre for Cosmoparticle Physics, Department of Physics, Stockholm University（宇宙粒子物理学奥斯卡·克莱因中心，物理系，斯德哥尔摩大学）；Dipartimento di Fisica e Astronomia, Universita di Bologna（物理与天文系，博洛尼亚大学）；INAF Istituto di Radioastronomia（意大利国家天体物理研究所射电天文台）；Université Paris Cité, CNRS, Astroparticule et Cosmologie（巴黎西岱大学，法国国家科学研究中心，亚原子物理与宇宙学）；Laboratory of Astrophysics, École Polytechnique Fédérale de Lausanne（天体物理学实验室，洛桑联邦理工学院）
