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The magnetised solar wind modulates the Galactic cosmic ray flux in the heliosphere up to rigidities as high as 40 GeV. In this work, we present a new and straightforward extension of the popular, but limited force-field model, thus…

High Energy Astrophysical Phenomena · Physics 2019-12-25 Marco Kuhlen , Philipp Mertsch

The very high energy (VHE) emission of the Central Molecular Zone (CMZ) is rarely modelled in 3D. Most approaches describe the morphology in 1D or simplify the diffusion to the isotropic case. In this work we show the impact of a realistic…

High Energy Astrophysical Phenomena · Physics 2024-04-19 J. Dörner , J. Becker Tjus , P. -S. Blomenkamp , H. Fichtner , A. Franckowiak , E. M. Zaninger

Pulsars have been invoked to explain the origin of recently observed high-energy Galactic cosmic-ray positrons. Since the positron propagation distance decreases with energy, the number of pulsars that can contribute to the observed…

High Energy Astrophysical Phenomena · Physics 2018-07-18 Ilias Cholis , Tanvi Karwal , Marc Kamionkowski

The bulk of the diffuse galactic gamma-ray emission above a few tens of GeV has been conventionally ascribed to the decay of neutral pions produced in cosmic-ray interactions with interstellar matter. Cosmic-ray electrons may, however, make…

Astrophysics · Physics 2008-11-26 T. A. Porter , R. J. Protheroe

The PAMELA collaboration recently released the $e^+$ absolute spectrum between 1 and 300 GeV in addition to the positron fraction and the $e^-$ spectrum previously measured in the same period. We use the newly developed three-dimensional…

High Energy Astrophysical Phenomena · Physics 2014-04-30 Daniele Gaggero , Dario Grasso , Luca Maccione , Giuseppe Di Bernardo , Carmelo Evoli

We report calculations of cosmic-ray proton, nuclei, antiproton, electron and positron energy spectra within a "two-halo model" of diffusive transport. The two halos represent a simple, physically consistent generalization of the standard…

High Energy Astrophysical Phenomena · Physics 2015-10-20 Nicola Tomassetti

The AMS-02 collaboration has just released its first result of the cosmic positron fraction $e^+/(e^-+e^+)$ with high precision up to $\sim 350$ GeV. The AMS-02 result shows the same trend with the previous PAMELA result, which requires…

High Energy Astrophysical Phenomena · Physics 2014-07-15 Qiang Yuan , Xiao-Jun Bi , Guo-Ming Chen , Yi-Qing Guo , Su-Jie Lin , Xinmin Zhang

Low energy cosmic rays are modulated by the solar activity when they propagation in the heliosphere, leading to ambiguities in understanding their acceleration at sources and propagation in the Milky Way. By means of the precise…

High Energy Astrophysical Phenomena · Physics 2020-07-29 Cheng-Rui Zhu , Qiang Yuan , Da-Ming Wei

The Alpha Magnetic Spectrometer (AMS-02), which is scheduled to be deployed onboard the International Space Station later this year, will be capable of measuring the composition and spectra of GeV-TeV cosmic rays with unprecedented…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Miguel Pato , Dan Hooper , Melanie Simet

The unprecedented quality of the data collected by the AMS-02 experiment onboard the International Space Station allowed us to address subtle questions concerning the origin and propagation of cosmic rays. Here we discuss the implications…

High Energy Astrophysical Phenomena · Physics 2019-06-05 Carmelo Evoli , Roberto Aloisio , Pasquale Blasi

Using a hybrid kinetic magnetohydrodynamic formalism incorporating the effects of pressure anisotropy, we simulate the evolution of a turbulent collisionless plasma in six different models covering the sub/super-sonic and…

High Energy Astrophysical Phenomena · Physics 2013-12-31 M. S. Nakwacki , J. Peralta-Ramos

Extended $\gamma$-ray emission has been observed around several nearby pulsars and is commonly interpreted as inverse-Compton radiation produced by relativistic electrons and positrons diffusing in the surrounding interstellar medium. In…

High Energy Astrophysical Phenomena · Physics 2026-04-01 Qian Zhong

Constraining the behavior of cosmic ray data observed at Earth requires a precise understanding of how the cosmic rays propagate in the interstellar medium. The interstellar medium is not homogeneous; although turbulent magnetic fields…

High Energy Astrophysical Phenomena · Physics 2016-05-25 J. Patrick Harding , Chris L. Fryer , Susan Mendel

In this article, we explore the anisotropic electron energy loss spectrum (EELS) in monolayer phosphorene based on ab-initio time dependent density functional theory calculations. Similar to black phosphorous, the EELS of undoped monolayer…

Mesoscale and Nanoscale Physics · Physics 2017-07-26 Barun Ghosh , Piyush Kumar , Anmol Thakur , Yogesh Singh Chauhan , Somnath Bhowmick , Amit Agarwal

We present a comprehensive discussion about the origin of the features in the leptonic component of the cosmic-ray spectrum. Working in the framework of a up-to-date CR transport scenario tuned on the most recent AMS-02 and Voyager data, we…

High Energy Astrophysical Phenomena · Physics 2020-03-09 Ottavio Fornieri , Daniele Gaggero , Dario Grasso

We derive all contributions to the dispersion measure (DM) of electromagnetic pulses to linear order in cosmological perturbations, including both density fluctuations and relativistic effects. We then use this result to calculate the power…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-30 David Alonso

The Alpha Magnetic Spectrometer (AMS-02) has provided unprecedented precision measurements of the electron and positron cosmic-ray fluxes and the positron fraction spectrum. At the higher energies, sources as energetic local pulsars, may…

High Energy Astrophysical Phenomena · Physics 2023-03-15 Ilias Cholis , Thressay Hoover

We investigate test-particle diffusion in dynamical turbulence based on a numerical approach presented before. For the turbulence we employ the nonlinear anisotropic dynamical turbulence model which takes into account wave propagation…

High Energy Astrophysical Phenomena · Physics 2016-09-28 Martin Heusen , Andreas Shalchi

Recently a cosmic ray propagation model has been introduced, where anisotropic diffusion is used as a mechanism to allow for $\mathcal{O}(100)$ km/s galactic winds. This model predicts a reduced antiproton background flux, suggesting an…

High Energy Astrophysical Phenomena · Physics 2010-12-06 Phillip Grajek , Kaoru Hagiwara

We investigate the anisotropic diffusion of cosmic rays in the large-scale Galactic magnetic field, where diffusion occurs at different rates along and across the magnetic field lines. To model this process, we use stochastic differential…

High Energy Astrophysical Phenomena · Physics 2025-06-17 Ala'a AL-Zetoun