Gamma ray lines are expected to be emitted as part of the afterglow of supernova explosions , because radioactive decay of freshly synthesised nuclei occurs .
Significant radioactive gamma ray line emission is expected from ^ { 56 } Ni and ^ { 44 } Ti decay on time scales of the initial explosion ( ^ { 56 } Ni , \tau \sim days ) and the young supernova remnant ( ^ { 44 } Ti , \tau \sim 90 years ) .
Less specific , and rather informative for the supernova population as a whole , are lessons from longer lived isotopes such as ^ { 26 } Al and ^ { 60 } Fe .
From isotopes of elements heavier than iron group elements , any interesting gamma-ray line emission is too faint to be observable .
Measurements with space-based gamma-ray telescopes have obtained interesting gamma ray line emissions from two core collapse events , Cas A and SN1987A , and one thermonuclear event , SN2014J .
We discuss INTEGRAL data from all above isotopes , including all line and continuum signatures from these two objects , and the surveys for more supernovae , that have been performed by gamma ray spectrometry .
Our objective here is to illustrate what can be learned from gamma-ray line emission properties about the explosions and their astrophysics .