12–23 Jul 2021
Online
Europe/Berlin timezone

The Origin of Galactic Cosmic Rays as Revealed by their Composition

15 Jul 2021, 18:00
1h 30m
04

04

Talk CRD | Cosmic Ray Direct Discussion

Speaker

Vincent Tatischeff (IJCLab)

Description

Galactic cosmic-rays (GCRs) are thought to be accelerated by the first order Fermi mechanism in strong shocks induced by massive star winds and supernova explosions sweeping across the interstellar medium (ISM). But the phase of the ISM from which the CRs are extracted has remained elusive up to now. Using the latest CR composition data from the AMS-02, Voyager-1 and SuperTIGER experiments, we show that the volatile elements of the CR material are mainly accelerated from a plasma of temperature of approximately 3 million Kelvin, which is typical of the hot and tenuous medium found in galactic superbubbles energized by the combined activities of massive star winds and core-collapse supernova explosions. In addition, we identify a CR component arising from acceleration of massive star winds in their termination shocks, which is responsible for the overabundance of 22-Ne in the GCR composition. The CR composition also shows evidence for a preferential acceleration of refractory elements contained in ISM dust. We suggest that this component arises from the acceleration of dust grains continuously injected into superbubbles through evaporation of adjacent molecular clouds. We derive the acceleration efficiencies for these various components and compare them to those predicted by the diffuse shock acceleration theory.

Keywords

Cosmic-ray composition; Particule acceleration; supernova remnants; Superbubbles

Subcategory Theoretical Results

Primary author

Co-authors

John C. Raymond (Harvard-Smithsonian Center for Astrophysics) Jean Duprat (IMPMC Paris) Stefano Gabici (Université de Paris, APC) Sarah Recchia (Dipartimento di Fisica Teorica, Universita di Torino)

Presentation materials