H-12 - The instep and steepening reflect overlapping helium and CNO flux components with a narrow source rigidity maximum, not a few foreground sources
Properties8
type
hypothesis
id
H-12
state
active
question
What causes the instep and steepening features of the UHECR spectrum?
statement
The instep feature (~13 EeV) and the steepening arise from the interplay of helium and carbon-nitrogen-oxygen mass components emitted by a source population with a narrow range of maximum rigidity - the succession of rather pure nuclear composition groups above 10 EeV - rather than from the distinctive spectrum of a small number of foreground sources contributing significantly to the total intensity.