Supernova Outburst Research Articles

The crab and cygnus a as gamma ray sources

The Crab is estimated to give a maximum nuclear γ-ray flux of 10−2 cm−2 s−1 from the decay of251Cf formed with253Cf during the supernova outburst. Although extrapolation of the radio and visual fluxes suggests the possibility of a flux as high as 10 γ cm−2 s−1 between 1 and 2 MeV, model calculations suggest that 7·10−5 γ cm−2 s−1 above about 10 MeV is more probable. Bremsstrahlung and Compton scattering yield considerably lower fluxes. Cygnus A, regarded as the result of a collision of matter and antimatter, should yield lower fluxes than the γ cm−2 s−1 estimated by Morrison. The radio flux suggests a π0 decay γ-flux of 4·10−5 γ cm−2 s−1. ForE>10 MeV, any γ-ray flux exceeding 5·10−5 γ cm−2 s−1 should be detectable from a balloon flown emulsion stack.

Californium-254 and Supernovae

It is suggested that the spontaneous fission of Cf254 with a half-life of 55 days is responsible for the form of the decay light-curves of supernovae of Type I which have an exponential form with a half-life of 55 nights. The way in which Cf254 may be synthesized in a supernova outburst, and reasons why the energy released by its decay may dominate all others are discussed. The presence of Tc in red giant stars and of Cf in Type I supernovae appears to be observational evidence that neutron capture processes on both a slow and a fast time-scale have been necessary to synthesize the heavy elements in their observed cosmic abundances.