Spectroscopic and photometric observations of SN1987A. V - Days 386-616

Abstract

Spectroscopic and photometric observations are presented of SN1987A in the Large Magellanic Cloud made between days 386 and 616 after the Kamiokande-II neutrino event. During this period the bolometric flux from the supernova measured over the U to M wavelength range has continued to decline faster than the Co-56 decay rate. By day 560 the flux in this wavelength range accounts for only half of that expected from Co-56 decay. The estimated total flux is consistent with Co-56 remaining the sole energy source of the supernova over the period considered.