The impact of the eROSITA bubbles on Galactic cosmic-ray transport

Fuente: arXiv
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Main Author: Schroer, Benedikt
Format: Preprint
Published: 2026
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author Schroer, Benedikt
author_facet Schroer, Benedikt
contents We propose that the observed spectral hardening in Galactic cosmic ray fluxes is governed by macroscopic Galactic outflows, such as the eROSITA bubbles, rather than microphysical variations in their scattering properties. Employing a phenomenological transport model, we show that an advective outflow boundary naturally reproduces the $300\,$GV hardening in secondary-to-primary ratios. Global fits to precision AMS-02 data yield an effective local inner halo boundary of $\sim 5\,$kpc and an outflow speed of $\sim 360\,$km/s, in striking agreement with independent multi-wavelength kinematic constraints of the eROSITA outflows. This interpretation provides a testable alternative to breaks in the effective diffusion coefficient, without increasing the number of free parameters.
format Preprint
id arxiv_https___arxiv_org_abs_2604_01815
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle The impact of the eROSITA bubbles on Galactic cosmic-ray transport
Schroer, Benedikt
High Energy Astrophysical Phenomena
We propose that the observed spectral hardening in Galactic cosmic ray fluxes is governed by macroscopic Galactic outflows, such as the eROSITA bubbles, rather than microphysical variations in their scattering properties. Employing a phenomenological transport model, we show that an advective outflow boundary naturally reproduces the $300\,$GV hardening in secondary-to-primary ratios. Global fits to precision AMS-02 data yield an effective local inner halo boundary of $\sim 5\,$kpc and an outflow speed of $\sim 360\,$km/s, in striking agreement with independent multi-wavelength kinematic constraints of the eROSITA outflows. This interpretation provides a testable alternative to breaks in the effective diffusion coefficient, without increasing the number of free parameters.
title The impact of the eROSITA bubbles on Galactic cosmic-ray transport
topic High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2604.01815