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Radio galaxies are promising candidates as the sources of ultrahigh energy cosmic rays (UHECRs). In this work, we examine if the stringent constraints imposed by the dipole and quadropole anisotropies as well as the UHECR spectrum and…

High Energy Astrophysical Phenomena · Physics 2022-07-06 Björn Eichmann , Michael Kachelrieß , Foteini Oikonomou

We investigate the multiwavelength emission from hadronic and leptonic cosmic rays (CRs) in bubbles around galaxies, analogous to the Fermi bubbles of the Milky Way. The bubbles are modeled using 3D magnetohydrodynamical (MHD) simulations,…

High Energy Astrophysical Phenomena · Physics 2022-08-24 Ellis R. Owen , H. -Y. Karen Yang

Spiral galaxies host dynamically important magnetic fields which can affect gas flows in the disks and halos. Total magnetic fields in spiral galaxies are strongest (up to 30 \muG) in the spiral arms where they are mostly turbulent or…

Astrophysics · Physics 2009-06-23 Rainer Beck

We study the synchrotron radio emission from extra-planar regions of star forming galaxies. We use ideal magneto-hydrodynamical (MHD) simulations of a rotating Milky Way-type disk galaxy with distributed star formation sites for three star…

Astrophysics of Galaxies · Physics 2020-01-08 Aditi Vijayan , Biman B. Nath , Prateek Sharma , Yuri Shchekinov

Cosmic rays are thought to escape their sources streaming along the local magnetic field lines. We show that this phenomenon generally leads to the excitation of both resonant and non-resonant streaming instabilities. The self-generated…

High Energy Astrophysical Phenomena · Physics 2022-03-02 Benedikt Schroer , Oreste Pezzi , Damiano Caprioli , Colby Haggerty , Pasquale Blasi

The polarized synchrotron data of the northern C-BASS survey show a surprisingly low linear polarization fraction, $\Pi\simeq 3\%$, while the magnetic field polarization features coherent structures over rather large angular scales. The low…

Astrophysics of Galaxies · Physics 2025-03-26 C. T. Becker , M. Kachelriess

We investigate the production of ultra-high-energy cosmic ray (UHECR) in relativistic jets from low-luminosity active galactic nuclei (LLAGN). We start by proposing a model for the UHECR contribution from the black holes (BHs) in LLAGN,…

High Energy Astrophysical Phenomena · Physics 2015-06-23 Ioana Dutan , Laurentiu I. Caramete

The full-sky multipole coefficients of the ultra-high energy cosmic ray (UHECR) flux have been measured for the first time by the Pierre Auger and Telescope Array collaborations using a joint data set with E > 10 EeV. We calculate these…

High Energy Astrophysical Phenomena · Physics 2015-06-23 P. G. Tinyakov , F. R. Urban

The Fermi Large Area Telescope (Fermi LAT) collaboration has recently reported on 50 months of measurements of the isotropic Extragalactic Gamma Ray Background (EGRB) spectrum between $100\mbox{MeV}$ and $820\mbox{GeV}$. Ultrahigh Energy…

High Energy Astrophysical Phenomena · Physics 2016-05-25 Eyal Gavish , David Eichler

We have performed the detailed numerical simulations on the propagation of the UHE protons in the energy range $E=(10^{19.5} - 10^{22.0}$) eV in the relatively strong extra-galactic magnetic field with strength $B= (10, 100)$ nG within…

Astrophysics · Physics 2015-06-24 Y. Ide , S. Nagataki , S. Tsubaki , H. Yoshiguchi , K. Sato

We study the propagation of ultra-high-energy cosmic rays (UHECR) in the Galaxy, concentrating on the energy range below the ankle in the spectrum at 4 EeV. A Monte-Carlo method, based on analytical solutions to the time-dependent diffusion…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Martin Pohl , David Eichler

UHECR propagation in a turbulent intergalactic magnetic field in the small-angle scattering regime is well understood for propagation distances much larger than the field coherence scale. The diffusion theory doesn't work and unexpected…

High Energy Astrophysical Phenomena · Physics 2023-07-26 K. Dolgikh , A. Korochkin , G. Rubtsov , D. Semikoz , I. Tkachev

Planned and ongoing campaigns for the acquisition of high-quality local measurements of the Galactic magnetic field (GMF) at interstellar cloud locations have generated intense interest in the use of such measurements to accurately…

High Energy Astrophysical Phenomena · Physics 2025-07-30 S. Romanopoulos , M. Mastorakis , V. Pavlidou

Relativistic electrons, seen in the large diffuse radio halo of the Coma cluster of galaxies, should scatter background photons to higher energies. We calculate the inverse Compton contributions from the microwave background, from the local…

Astrophysics · Physics 2011-05-23 Torsten A. Ensslin , Peter L. Biermann

A new study of the diffuse Galactic gamma-ray continuum radiation is presented, using a cosmic-ray propagation model which includes nucleons, antiprotons, electrons, positrons, and synchrotron radiation. Our treatment of the inverse Compton…

Astrophysics · Physics 2009-10-31 A. W. Strong , I. V. Moskalenko , O. Reimer

We explore the possibility that the recently detected dipole anisotropy in the arrival directions of~$>8$~EeV ultra-high energy cosmic-rays (UHECRs) arises due to the large-scale structure (LSS). We assume that the cosmic ray sources follow…

High Energy Astrophysical Phenomena · Physics 2017-12-06 Noemie Globus , Tsvi Piran

We study the propagation of ultra-high-energy cosmic rays in the magnetised cosmic web. We focus on the particular case of highly magnetised voids ($B \sim \text{nG}$), using the upper bounds from the Planck satellite. The cosmic web was…

High Energy Astrophysical Phenomena · Physics 2017-08-02 Rafael Alves Batista , Min-Su Shin , Julien Devriendt , Dmitri Semikoz , Guenter Sigl

We present a study of the Milky Way disk and halo magnetic field, determined from observations of Faraday rotation measure (RM) towards 641 polarized extragalactic radio sources in the Galactic longitude range 100-117 degs, within 30 degs…

We examine the constraints imposed by Faraday rotation measures of extragalactic point sources on the structure of the magnetic field in the halo of our Galaxy. Guided by radio polarization observations of external spiral galaxies, we look…

Astrophysics of Galaxies · Physics 2017-03-29 Philippe Terral , Katia Ferriere

Radio continuum observations of external galaxies provide us with an excellent outside view on the distribution of cosmic-ray electrons in the disc and halo. In this review, we summarise the current state of what we have learned from…

Astrophysics of Galaxies · Physics 2021-12-16 Volker Heesen