Assertion: astronomer's number | /r/HasSubevent | gamma-ray emission
Facets:
Source sentences:
text: Work by Eugene Feenberg and Henry Primakoff in 1948, Sachio Hayakawa and I.B. Hutchinson in 1952, and, especially, Philip Morrison in 1958 had led scientists to believe that a number of different processes which were occurring in the universe would result in gamma-ray emission.