Galactic Cosmic-Ray Transport in the Giant Circumgalactic Medium Halo
- 1Deutsches Elektronen Synchrotron DESY
Abstract
Recent observations have revealed that the Milky Way is embedded in a massive circumgalactic medium (CGM) extending to several hundred kpc. Such an extended gaseous halo acts as both a reservoir of baryons and potentially as a confinement volume for Galactic cosmic rays (CRs). We investigate CR transport in this giant Galactic halo and compare its properties with those of conventional small-halo models. In the giant-halo scenario, the halo height is no longer a free parameter, but instead relates to the extent of the source region. We show that CR transport within the source region remains similar to that in small-halo models, while substantial differences emerge at larger distances. In the giant-halo scenario, CRs develop an extended approximately 1/ r spatial tail and exhibit a broader age distribution than the small-halo case. This model is shown to be consistent with current secondary-to-primary CR measurements. We further find that uncertainties associated with Galactic gas distributions are comparable to those arising from nuclear spallation cross sections. These results suggest that the giant-halo model provides a physically motivated alternative to conventional small-halo models and may have important implications for diffuse gamma-ray and neutrino emission from the Galactic environment.
Related
- The BRIDGE Survey. I. Metallicities and Physical Properties of Gas Probing the Circumgalactic Medium at Cosmic Noon
- Cosmic rays in galaxy halos I: the circumgalactic transport rate and a dynamically significant cosmic-ray reservoir
- Modulation of Galactic Cosmic Rays in the Very Local Interstellar Medium: Energy and Species Dependence
- Turbulent Transport of Galactic Magnetic Fields into Cosmic Voids: Insights from IllustrisTNG
- An Implicit Conservative Finite Volume Scheme with Poisson Brackets for the Steady-State Transport of Galactic Cosmic Rays
BibTeX
@article{li2026galactic,
title = {{Galactic Cosmic-Ray Transport in the Giant Circumgalactic Medium Halo}},
author = {Chao-Ming Li and Andrew M. Taylor},
journal = {The Astrophysical Journal},
year = {2026},
month = nov,
doi = {10.3847/1538-4357/aeaba1},
url = {https://iopscience.iop.org/article/10.3847/1538-4357/aeaba1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Galactic Cosmic-Ray Transport in the Giant Circumgalactic Medium Halo
AU - Chao-Ming Li
AU - Andrew M. Taylor
PY - 2026
DA - 2026/11/03
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/aeaba1
UR - https://iopscience.iop.org/article/10.3847/1538-4357/aeaba1
AB - Recent observations have revealed that the Milky Way is embedded in a massive circumgalactic medium (CGM) extending to several hundred kpc. Such an extended gaseous halo acts as both a reservoir of baryons and potentially as a confinement volume for Galactic cosmic rays (CRs). We investigate CR transport in this giant Galactic halo and compare its properties with those of conventional small-halo models. In the giant-halo scenario, the halo height is no longer a free parameter, but instead relates to the extent of the source region. We show that CR transport within the source region remains similar to that in small-halo models, while substantial differences emerge at larger distances. In the giant-halo scenario, CRs develop an extended approximately 1/ r spatial tail and exhibit a broader age distribution than the small-halo case. This model is shown to be consistent with current secondary-to-primary CR measurements. We further find that uncertainties associated with Galactic gas distributions are comparable to those arising from nuclear spallation cross sections. These results suggest that the giant-halo model provides a physically motivated alternative to conventional small-halo models and may have important implications for diffuse gamma-ray and neutrino emission from the Galactic environment.
SN - 1538-4357
SN - 0004-637X
ER -