SN 1998bw at late phases

• We present observations of the peculiar supernova SN 1998bw, which was probably associated with GRB 980435. The photometric and spectroscopic evolution is monitored up to 500 days past explosion. We also present modeling based on spherically symmetric, massive progenitor models and very energetic explosions. The models allow line identification and clearly show the importance of mixing. From the late light curves, we estimate that similar to 0.3-0.9 M. of ejected Ni-56 is required to power the supernova.

Nyckelord

gamma rays : bursts

nuclear reactions, nucleosynthesis, abundances supernovae : individual (SN 1998bw)

gamma-ray burst

25 april 1998

late spectral evolution

unusual supernova

light curves

emission

grb-980425

sn-1987a

ni-56

mass

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ref (ämneskategori)

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