The circumnuclear environment of IRAS 20551-4250 a case study of
  AGN/Starburst connection for JWST
  We present a general review of the current knowledge of IRAS 20551-4250 and
its circumnuclear environment. This Ultraluminous Infrared Galaxy is one of the
most puzzling sources of its class in the nearby Universe: the near-IR spectrum
is typical of a galaxy experiencing a very intense starburst, but a highly
obscured active nucleus is identified beyond 5 micron and possibly dominates
the mid-IR energy output of the system. At longer wavelengths star formation is
again the main driver of the global spectral shape and features. We interpret
all the available IR diagnostics in the framework of simultaneous black hole
growth and star formation, and discuss the key properties that make this source
an ideal laboratory for the forthcoming James Webb Space Telescope.
