出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We report the first detection at multiple radio wavelengths (13, 6, and 3.6 cm) of 18 compact
sources within both nuclei of the Ultra Luminous Infra-Red Galaxy (ULIRG) Arp 220. In just
over half of the sources we find that the observed spectra are consistent with the standard model
of powerful Type IIn supernovae interacting with their pre-explosion stellar wind. The rate of appearance
of new radio sources ascribed to these supernova events suggests that a large fraction of
core-collapse supernovae in Arp 220 are highly luminous, possibly implying a radically different
stellar initial mass function (IMF) or stellar evolution compared to galactic disks. A second group
of sources, consisting of the brightest and longest monitored sources at 18 cm, do not easily fit
the radio supernova model. We propose that these are young supernova remnants that have just
begun interacting with their surrounding dense ISM.
