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We present an analysis of the origin and properties of the circum-galactic medium (CGM) in a suite of 11 cosmological zoom simulations resembling present day spiral galaxies. On average the galaxies retain about 50\% of the cosmic fraction…

Galactic cosmic ray transport relies on the existence of turbulence on scales comparable with the gyration radius of the particles and with wavenumber vector oriented along the local magnetic field. In the standard picture, in which…

High Energy Astrophysical Phenomena · Physics 2023-12-29 O. Pezzi , P. Blasi

We have studied the impact of cosmic-ray acceleration in SNR on the spectra of cosmic-ray nuclei in the Galaxy using a series expansion of the propagation equation, which allows us to use analytical solutions for part of the problem and an…

Astrophysics · Physics 2009-11-10 I. Buesching , A. Kopp , M. Pohl , R. Schlickeiser , C. Perrot , I. Grenier

The theory of Galactic Winds, driven by the cosmic-ray pressure gradient, is reviewed both on the magnetohydrodynamic and on the kinetic level. In this picture the magnetic field of the Galaxy above the dense gas disk is assumed to have a…

High Energy Astrophysical Phenomena · Physics 2014-11-06 Heinrich J. Völk

The Cosmic Rays propagation was studied in details using the HelMod-2D Monte Carlo code, that includes a general description of the diffusion tensor, and polar magnetic-field. The Numerical Approach used in this work is based on a set of…

Earth and Planetary Astrophysics · Physics 2013-07-22 P. Bobik , G. Boella , M. J. Boschini , S. Della Torre , M. Gervasi , D. Grandi , G. La Vacca , K. Kudela , S. Pensotti , P. G. Rancoita , D. Rozza , M. Tacconi

The formation of protostellar discs is severely hampered by magnetic braking, as long as magnetic fields remain frozen in the gas. The latter condition depends on the levels of ionisation that characterise the innermost regions of a…

Astrophysics of Galaxies · Physics 2015-06-22 Marco Padovani , Daniele Galli , Patrick Hennebelle , Benoît Commerçon , Marc Joos

We present a census of neutral gas in the Milky Way disk and halo down to limiting column densities of $N$(HI)$\sim10^{14}$ cm$^{-2}$ using measurements of HI Lyman-series absorption from the Far Ultraviolet Spectroscopic Explorer (FUSE).…

The galactic diffuse $\gamma$-ray emission, as seen by Fermi Large Area Telescope (LAT), shows a sharp peak in the region around 4 kpc from the Galactic center, which can be interpreted either as due to an enhanced density of cosmic-ray…

High Energy Astrophysical Phenomena · Physics 2021-03-23 Giada Peron , Felix Aharonian , Sabrina Casanova , Ruizhi Yang , Roberta Zanin

Understanding the processes occurring in the nuclear disk of our Galaxy is interesting in its own right, as part of the Milky Way Galaxy, but also because it is the closest galactic nucleus. It has been more than two decades since it was…

Astrophysics · Physics 2009-11-13 F. Yusef-Zadeh , M. Wardle , S. Roy

We have developed a model which aims to reproduce observational data of many kinds related to cosmic-ray (CR) origin and propagation: direct measurements of nuclei, antiprotons, electrons and positrons, gamma-rays, and synchrotron…

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

The tendency of some diffuse interstellar band (DIB) carriers to concentrate in the outer, UV-illuminated layers of molecular clouds (MCs)--the ``skin effect''--makes their spatial distribution a powerful probe of their physical nature. We…

Astrophysics of Galaxies · Physics 2026-03-09 He Zhao , Lu Li

This paper examines the cosmic ray He and C nuclei spectra below ~1 GeV/nuc, as well as the very rapid increase in the He/C ratio below ~100 MeV/nuc, measured by Voyager 1 beyond the heliopause. Using a simple Leaky Box Model (LBM) for…

Space Physics · Physics 2017-12-01 W. R. Webber

Recent work by Pringle and by Maloney, Begelman & Pringle has shown that geometrically thin, optically thick, accretion disks are unstable to warping driven by radiation torque from the central source. In this paper we generalize the study…

Astrophysics · Physics 2009-10-30 Philip R. Maloney , Mitchell C. Begelman , Michael A. Nowak

We set new constraints on a seven-dimensional space of cosmological parameters within the class of inflationary adiabatic models. We use the angular power spectrum of the cosmic microwave background measured over a wide range of \ell in the…

Thanks to tremendous experimental efforts, galactic cosmic-ray fluxes are being measured up to the unprecedented per cent precision level. The logarithmic slope of these fluxes is a crucial quantity that promises us information on the…

High Energy Astrophysical Phenomena · Physics 2025-03-21 M. Vecchi , P. -I. Batista , E. F. Bueno , L. Derome , Y. Génolini , D. Maurin

The transport of charged energetic particles in the presence of strong intermittent heliospheric turbulence is computationally analyzed based on known properties of the interplanetary magnetic field and solar wind plasma at 1 Astronomical…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Fathallah Alouani-Bibi , Jakobus A. le Roux

Nowadays, the calculation of the Galactic Cosmic Rays diffusion coefficient with direct microscopic numerical simulations is a widespread approach. In this work, we investigated the numerical limits for such calculations and demonstrated…

Instrumentation and Methods for Astrophysics · Physics 2026-05-14 Vladimir Yurovsky , Ilya Kudryashov

The existence of the cosmic ray Halo in our Galaxy has been discussed for more than half a century. If it is real it could help to explain some puzzling features of the cosmic ray flux: its small radial gradient, nearly perfect isotropy and…

Astrophysics of Galaxies · Physics 2015-06-19 Anatoly Erlykin , Arnold Wolfendale

A novel phenomenon among the recently observed Geminga pulsar halo is the presence of distinct radiation morphology at high energies, while no extended radiation is detected in the 10-500 GeV energy band within a $40\degree\times40\degree$…

High Energy Astrophysical Phenomena · Physics 2025-09-03 Lin Nie , Yu-Hai Ge , Yi-Qing Guo , Si-Ming Liu

Electron-capture (EC) unstable species in Galactic cosmic rays constrain the time elapsed between nucleosynthesis and acceleration. They have also been advocated as tracers of reacceleration or gas inhomogeneities during their transport.…

High Energy Astrophysical Phenomena · Physics 2026-02-09 M. Borchiellini , D. Maurin , M. Vecchi