The relation between the observed mass distribution for compact stars and the mechanism for supernova explosions

The observed mass distribution for the compact remnants of massive stars (neutron stars and black holes) and its relationship to the possible mechanism of ejection of the envelopes of type II and Ib/c supernovae are analyzed. The observed lack of compact remnants with masses 1.5–3 M _⊙ suggests a magneto-rotational mechanism for the supernovae, and a soft equation of state for neutron stars with limiting masses near 1.5 M _⊙. The observational consequences of this hypothesis are discussed.