Minkowski's Object: A STARBURST TRIGGERED BY A RADIO JET

New radio and optical images of Minkowski's object, a peculiar blue object near the elliptical galaxy NGC 541 in the cluster Abell 194, are presented. The observations show that the object is a region with bright optical line and continuum emission which are morphologically related and associated with a radio jet emanating from NGC 541. Optical emission is brightest near the edges of the jet, correlated with the absence of polarized radio emission, and filamentary downstream where the radio jet is deflected and decollimated. Minkowski's object exhibits unusually bright optical continuum emission, and its spectrum resembles those of galaxies dominated by giant H II regions. Observations of the prototypical starburst galaxy NGC 7714 (Weedman et al., 1981) confirm that the optical emission from Minkowski's object is caused by the photoionization of gas by type O and B stars. 71 references.