On the initial energy of supernova remnants

An examination of the histogram of the supernova remnants radii allows one to deduce: (1) some support for the existence of a fairly dense galactic halo at least up to a few kpc from the galactic plane; (2) a first approximation for the initial energy distribution. Although the precise shape is still in doubt and various possibilities exist, one can conclude that the supernova rate should be no less than 1/150 SN yr^–1, and no more than 1/70 SN yr^–1; the average initial energy should be larger than 1.4×10⁴⁹ erg.