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Low-luminosity gamma-ray bursts (LL GRBs), a subclass of the most powerful transients in the Universe, remain promising sources of high-energy astrophysical neutrinos, despite strong IceCube constraints on typical long GRBs. In this work, a…

High Energy Astrophysical Phenomena · Physics 2026-02-03 Shiqi Yu , Bing Theodore Zhang

Starburst galaxies (SBGs) with copious massive stars and supernova (SN) explosions are the sites of active cosmic-ray production. Based on the predictions of nonlinear diffusive shock acceleration theory, we model the cosmic-ray proton…

High Energy Astrophysical Phenomena · Physics 2021-03-17 Ji-Hoon Ha , Dongsu Ryu , Hyesung Kang

We investigate the impact of cosmic rays (CRs) on galactic outflows from a multi-phase interstellar medium with solar neighbourhood conditions. The three-dimensional magneto-hydrodynamical simulations include CRs as a relativistic fluid in…

Astrophysics of Galaxies · Physics 2018-07-11 Philipp Girichidis , Thorsten Naab , Michał Hanasz , Stefanie Walch

Recently, the {\it{Fermi}} space telescope has discovered two large $\gamma$-ray emission regions, the so-called "Fermi bubbles", that extend up to $\sim 50^\circ$ above and below the Galactic center. The $\gamma$-ray emission from the…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Satyendra Thoudam

The High Energy Stereoscopic System (HESS), the Major Atmospheric Gamma-ray Imaging Cherenkov Telescope (MAGIC), and the Very Energetic Radiation Imaging Telescope Array System (VERITAS) have observed diffuse gamma-ray emission strongly…

High Energy Astrophysical Phenomena · Physics 2022-03-14 Andrés Scherer , Jorge Cuadra , Franz E. Bauer

The origin of the Fermi bubbles recently detected by the Fermi Gamma-ray Space Telescope in the inner Galaxy is mysterious. In the companion paper Guo & Mathews (Paper I), we use hydrodynamic simulations to show that they could be produced…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Fulai Guo , William G. Mathews , Gregory Dobler , S. Peng Oh

Cosmic rays (CRs) are an integral component of the interstellar medium, producing broadband emission while interacting with other Galactic matter components like the interstellar gas or magnetic fields. In addition to observations,…

High Energy Astrophysical Phenomena · Physics 2022-10-12 Julia Thaler , Ralf Kissmann , Olaf Reimer

The nearby Large Magellanic Cloud (LMC) provides a rare opportunity of a spatially resolved view of an external star-forming galaxy in gamma-rays. The LMC was detected at 0.1-100GeV as an extended source with CGRO/EGRET and using early…

High Energy Astrophysical Phenomena · Physics 2015-11-09 LAT Collaboration

We model multiwavelength afterglow data from the short Gamma-Ray Burst (GRB) 090510 using a combined leptonic-hadronic model of synchrotron radiation from an adiabatic blast wave. High energy, >100 MeV, emission in our model is dominated by…

High Energy Astrophysical Phenomena · Physics 2010-11-09 Soebur Razzaque

Super-bubbles are shells in the interstellar medium produced by the simultaneous explosions of many supernova remnants. The solutions of the mathematical diffusion and of the Fourier expansion in 1D, 2D and 3D were deduced in order to…

Astrophysics · Physics 2011-09-20 Lorenzo Zaninetti

Multiwavelength observations suggest that clusters are reservoirs of vast amounts relativistic electrons and positrons that are either injected into and accelerated directly in the intra-cluster medium, or produced as secondary pairs by…

High Energy Astrophysical Phenomena · Physics 2019-08-15 Stephan Zimmer , Jan Conrad , Anders Pinzke

Several observations from Fermi-LAT, up to few hundred GeV, and from H.E.S.S., up to $\sim$ 10 TeV, reported an intense $\gamma$-ray emission from the inner part of the Galactic plane. After the subtraction of point-like contributions, the…

High Energy Astrophysical Phenomena · Physics 2015-08-18 Daniele Gaggero , Dario Grasso , Antonio Marinelli , Alfredo Urbano , Mauro Valli

The high-energy diffuse gamma-ray emission and neutrino emission are expected from the Galactic plane, generated by hadronuclear interactions between cosmic rays (CR) and interstellar medium (ISM). Therefore, measurements of these diffuse…

High Energy Astrophysical Phenomena · Physics 2024-03-19 Kai Yan , Ruo-Yu Liu , Rui Zhang , Chao-Ming Li , Qiang Yuan , Xiang-Yu Wang

We discuss particle production in the high-energy, small-x limit of QCD where the gluon density of hadrons is expected to become nonperturbatively large. Strong modifications of the phase-space distribution of produced particles as compared…

High Energy Physics - Phenomenology · Physics 2009-11-10 H. J. Drescher , A. Dumitru , M. Strikman

The discovery of diffuse synchrotron radio emission and, more recently, of the hard X-ray (HXR) tails have triggered a growing interest about non-thermal phenomena in galaxy clusters. After a brief review of the most important evidences for…

Astrophysics · Physics 2009-11-10 Gianfranco Brunetti

Diffuse emission in gamma-rays and neutrinos are produced by the interaction of cosmic rays with the interstellar medium. Below some hundreds of TeV, the sources of these cosmic rays are most likely Galactic. Hence, observations of…

High Energy Astrophysical Phenomena · Physics 2025-09-25 Anton Stall , Philipp Mertsch

Cosmic rays, along with stellar radiation and magnetic fields, are known to make up a significant fraction of the energy density of galaxies such as the Milky Way. When cosmic rays interact in the interstellar medium, they produce gamma-ray…

Context: Molecular data of extreme environments, such as Arp 220, but also NGC 253, show evidence for extremely high cosmic ray (CR) rates (10^3-10^4 * Milky Way) and mechanical heating from supernova driven turbulence. Aims: The…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 R. Meijerink , M. Spaans , A. F. Loenen , P. P. van der Werf

Odd radio circles (ORCs) are newly discovered extragalactic radio objects with unknown origin. In this work, we carry out three-dimensional cosmic-ray (CR) magnetohydrodynamic simulations using the FLASH code and predict the radio…

High Energy Astrophysical Phenomena · Physics 2024-08-22 Yen-Hsing Lin , H. -Y. Karen Yang

A fraction of gamma-ray bursts exhibit distinct spectral features in their prompt emission below few 10s of keV that exceed simple extrapolations of the low-energy power-law portion of the Band spectral model. This is also true for the…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Katsuaki Asano , Susumu Inoue , Peter Meszaros