Digging deep into the ULIRG phenomenon: When radio beats dust
  Luminous and Ultra-Luminous Infrared Galaxies (U/LIRGs) do also radiate
copious amounts of radio emission, both thermal (free-free) and non-thermal
(mainly synchrotron). This is very handy since, unlike optical and infra-red
observations, radio is not obscured by the ubiquitous dust present in U/LIRGs,
which allows a direct view of the ongoing activity in the hearts of those
prolific star-forming galaxies. Here, I first justify the need for this
high-angular resolution radio studies of local U/LIRGs, discuss the energy
budget and the magnetic field, as well as IC and synchrotron losses in U/LIRGs,
and present some selected results obtained by our team on high-angular
resolution radio continuum studies of U/LIRGs. Among other results, I show the
impressive discovery of an extremely prolific supernova factory in the central
~150 pc of the galaxy Arp 299-A (D=45 Mpc) and the monitoring of a large number
of very compact radio sources in it, the detection and precise location of the
long-sought AGN in Arp 299-A. A movie showing the appearance and disappearance
of new SNe in Arp 299A can be found at
http://www.iaa.es/~torres/research/arp299a.html. All those results demonstrate
that very-high angular resolution studies of nearby U/LIRGs are of high
relevance for the comprehension of both local and high-z starbursting galaxies.
