1. Observations: Cosmic rays
Martin Pohl

2. Topics Isotopic composition of cosmic rays Low-energy cosmic rays
Injection into shock acceleration
Structure of acceleration regions
Antimatter
Nucleosynthesis in accretion flows

3. Topics What is the flux of low-energy cosmic rays?
Where exactly are cosmic rays produced?

4. Low-energy cosmic rays
Antimatter production:
Nucleosynthesis or cosmic-ray interactions?
Positrons start with less than a few MeV
High bulge/disk needs explanation

5. Low-energy cosmic rays
Cosmic-ray interactions:
Collisions with CNO, e.g.
Production rate is 𝑸=𝟒𝝅 𝑵 𝑪𝑵𝑶 𝝈 𝝋 𝑪𝑹
Predictions for nuclear lines below current sensitivity

6. Low-energy cosmic rays
Nucleosynthesis
Should trace novae, WR stars, etc.
Cosmic-ray interactions:
Requires high flux of low-energy cosmic rays
Could relate to spurious activity of Galactic center
May explain excess ionization at Galactic center

7. CR production sites We know the process: Shock acceleration:
Significant energy gain
by multiple shock crossing
Injection is key
Role of dust?

8. Introduction Expansion into wind zone for core-collapse SNe Typ Ic:
Wolf-Rayet progenitor

9. CR production sites
Solar-system abundances 19% massive-star abund. + 81% SS
Refractories preferred,
Dust?
Slope 0.6
Murphy et al. 2016

10. CR production sites Isotopic composition around 100 MeV/nuc
60Fe has half-life yr
Refractories preferred
Dust?
Slope 0.6
Binns et al. 2016

11. CR production sites
60Fe is produced in core-collapse and found in ejecta, not in wind
Acceleration at reverse shock?
High low-energy flux
for small acceleration rate
Composition enriched
Problem: Most particles should
be accelerated by forward shock
at late phase
Refractories preferred
Dust?
Slope 0.6

12. CR production sites
60Fe is produced in core-collapse and found in ejecta, not in wind
Use 20% massive star / 80% solar system to estimate RMS (red)
Production calculations in
OB associations by
Woosley & Heger
Chieffi & Limongi
OB associations needed?
Little time for propagation to Earth
Refractories preferred
Dust?
Slope 0.6
Binns et al. 2016

13. Summary What do we need to know?
Positron yields by novae and other sites of nucleosynthesis
Intensity of nuclear excitation lines
Isotopic yields in supernova ejecta
Dust formation in ejecta, winds, and OB associations
Propagation properties of low-energy cosmic rays
Location of nearby sources