Current star formation in post-starburst galaxies?

Radio continuum observations are a probe of star formation in galaxies and are unaffected by dust extinction. Observations of the distant rich cluster Cl 0939+4713 have detected radio galaxies classified as post-starburst (k+a) on the basis of their optical spectra, and presumably this situation arises from heavily dust-obscured star formation. We present the results of a radio continuum survey of post-starburst galaxies identified by Zabludoff and coworkers from the Las Campanas Redshift Survey. This sample was selected using very stringent criteria and therefore provides an estimate on the incidence of potential star formation in galaxies whose optical spectra exhibit the strongest post-starburst features. We detected two of 15 such galaxies at radio luminosities consistent with moderate levels of star formation. This result underscores the potential importance of dust extinction when one investigates star formation in galaxies.