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The formation mechanism of the hot gaseous halo associated with the Milky Way Galaxy is still under debate. We report new observational constraints on the gaseous halo using 107 lines-of-sight of the Suzaku X-ray observations at…

Astrophysics of Galaxies · Physics 2018-08-08 Shinya Nakashima , Yoshiyuki Inoue , Noriko Yamasaki , Yoshiaki Sofue , Jun Kataoka , Kazuhiro Sakai

The problem of cosmic-ray scattering in the turbulent electromagnetic fields of the interstellar medium and the solar wind is of great importance due to the variety of applications of the resulting diffusion coefficients. Examples are…

High Energy Astrophysical Phenomena · Physics 2015-05-20 R. C. Tautz

Determining the velocity distribution of halo stars is essential for estimating the mass of the Milky Way and for inferring its formation history. Since the stellar halo is a dynamically hot system, the velocity distribution of halo stars…

Astrophysics of Galaxies · Physics 2017-06-14 Kohei Hattori , Monica Valluri , Sarah R. Loebman , Eric F. Bell

Theoretical and observational arguments suggest that there is a large amount of hot ($\sim 10^6$ K), diffuse gas residing in the Milky Way's halo, while its total mass and spatial distribution are still unclear. In this work, we present a…

Astrophysics of Galaxies · Physics 2020-05-06 Xiang-Er Fang , Fulai Guo , Ye-Fei Yuan

We present the first dynamically and thermally self-consistent calculations of fast adiabatically expanding gas flows from the Galactic disk into the halo. It is shown that in a hot plasma (T >= 10^6 K) with a high overpressure with respect…

Astrophysics · Physics 2007-05-23 Dieter Breitschwerdt , Thomas Schmutzler

We study the problem of the escape and transport of Cosmic-Rays (CR) from a source embedded in a fully ionised, hot phase of the interstellar medium (HIM). In particular, we model the CR escape and their propagation in the source vicinity…

High Energy Astrophysical Phenomena · Physics 2019-03-13 L. Nava , S. Recchia , S. Gabici , A. Marcowith , L. Brahimi , V. Ptuskin

A self-consistent model of a one-dimensional cosmic-ray (CR) halo around the Galactic disk is formulated with the restriction to a minimum number of free parameters. It is demonstrated that the turbulent cascade of MHD waves does not…

High Energy Astrophysical Phenomena · Physics 2020-11-18 V. A. Dogiel , A. V. Ivlev , D. O. Chernyshov , C. -M. Ko

The Hypervelocity Star survey presents the currently largest sample of radial velocity measurements of halo stars out to 80 kpc. We apply spherical Jeans modeling to these data in order to derive the mass profile of the Galaxy. We restrict…

Astrophysics of Galaxies · Physics 2010-08-31 Oleg Y. Gnedin , Warren R. Brown , Margaret J. Geller , Scott J. Kenyon

The mass assembly history of the Milky Way can inform both theory of galaxy formation and the underlying cosmological model. Thus, observational constraints on the properties of both its baryonic and dark matter contents are sought. Here we…

Astrophysics of Galaxies · Physics 2017-01-24 Elena M. Rossi , T. Marchetti , M. Cacciato , M. Kuiack , R. Sari

In a previous study (Maurin et al., 2001), we explored the set of parameters describing diffusive propagation of cosmic rays (galactic convection, reacceleration, halo thickness, spectral index and normalization of the diffusion…

Astrophysics · Physics 2009-11-07 David Maurin , Richard Taillet , Fiorenza Donato

Numerical modeling of galactic cosmic rays (GCRs) penetration through the heliosphere to the vicinity of the Sun is considered. Galactic cosmic rays are charged particles with energies exceeding 10 MeV/nucl., originating from far beyond the…

High Energy Astrophysical Phenomena · Physics 2025-09-04 D. A. Shestakov , V. V. Izmodenov

We study winds in high redshift galaxies driven by a relativistic cosmic ray (proton) component in addition to the hot thermal gas component. Cosmic rays (CRs) are likely to be efficiently generated in supernova shocks inside galaxies. We…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Saumyadip Samui , Kandaswamy Subramanian , Raghunathan Srianand

We show that the well-known discrepancy between the radial dependence of the Galactic cosmic ray (CR) nucleon distribution, as inferred most recently from EGRET observations of diffuse gamma-rays above 100 MeV, and of the most likely CR…

Astrophysics · Physics 2009-11-07 D. Breitschwerdt , V. A. Dogiel , H. J. Voelk

We re-analyse the velocity-dispersion profile sigma(r) at radii r>10 kpc in the Galactic stellar halo, recently derived by Battaglia et al. (2005), who concluded that, for constant velocity anisotropy of the tracers, these data rule out a…

Astrophysics · Physics 2009-11-11 Walter Dehnen , Dean McLaughlin , Jalpesh Sachania

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

We use K-giant stars selected from the LAMOST DR5 to study the variation of the rotational velocity of the galactic halo at different space positions. Modelling the rotational velocity distribution with both the halo and disk components, we…

Astrophysics of Galaxies · Physics 2020-08-26 Hao Tian , Chao Liu , Yougang Wang , Yan Xu , Chengqun Yang , Bo Zhang , Xiang-Xiang Xue

Gamma rays trace accelerated particles, and the observed flux of extragalactic gamma rays therefore constrains the global efficiency for particle acceleration. Extragalactic jets in active galactic nuclei can account for the gamma ray…

Astrophysics · Physics 2014-10-13 Karl Mannheim

The physical processes involved in diffusion of Galactic cosmic rays in the interstellar medium are addressed. We study the possibility that the nonlinear MHD cascade sets the power-law spectrum of turbulence which scatters charged…

Astrophysics · Physics 2008-11-26 V. S. Ptuskin , I. V. Moskalenko , F. C. Jones , A. W. Strong , V. N. Zirakashvili

The arrival directions of Galactic cosmic rays exhibit anisotropies up to the level of one per-mille over various angular scales. Recent observations of TeV-PeV cosmic rays show that the dipole anisotropy has a strong energy dependence with…

High Energy Astrophysical Phenomena · Physics 2019-05-22 Markus Ahlers

The velocity anisotropy of particles inside dark matter (DM) haloes is an important physical quantity, which is required for the accurate modelling of mass profiles of galaxies and clusters of galaxies. It is typically measured using the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Radoslaw Wojtak , Stefan Gottloeber , Anatoly Klypin