Astrophysical relevance of $\gamma$ transition energies

TL;DR

This paper identifies the gamma energy range crucial for astrophysical reactions, showing that 2-4 MeV gamma energies dominate the impact on reaction rates, especially via electric dipole transitions, aiding better modeling of astrophysical processes.

Contribution

It clarifies the specific gamma energy range and transition types that significantly influence astrophysical reaction rates, improving the understanding of gamma strength modifications.

Findings

Maximal contributions for gamma energies of 2-4 MeV.

Electric dipole transitions dominate under certain conditions.

Quantum selection rules can isolate contributions from specific states.

Abstract

The relevant gamma energy range is explicitly identified where additional gamma$ strength has to be located for having an impact on astrophysically relevant reactions. It is shown that folding the energy dependences of the transmission coefficients and the level density leads to maximal contributions for gamma energies of 2<=E_gamma<=4 MeV unless quantum selection rules allow isolated states to contribute. Under this condition, electric dipole transitions dominate. These findings allow to more accurately judge the relevance of modifications of the \gamma strength for astrophysics.