SHOW SED [Frequency [FileName]] Display the SED, computed by the "SED" widget from images (using the FLUX command) or from UV Tables (by fitting a simple model using UV_FIT), and fit a simple power law model through it. Frequency is the reference frequency in GHz at which the flux is computed. FileName is the data file produced by the "SED" widget. If Frequency or Filename are not specified, their last values are re-used.