Central regions of LIRGs: rings, hidden starbursts, Supernovae and star
  clusters
  We study star formation (SF) in very active environments, in luminous IR
galaxies, which are often interacting. A variety of phenomena are detected,
such as central starbursts, circumnuclear SF, obscured SNe tracing the history
of recent SF, massive super star clusters, and sites of strong off-nuclear SF.
All of these can be ultimately used to define the sequence of triggering and
propagation of star-formation and interplay with nuclear activity in the lives
of gas rich galaxy interactions and mergers. In this paper we present analysis
of high-spatial resolution integral field spectroscopy of central regions of
two interacting LIRGs. We detect a nuclear 3.3 um PAH ring around the core of
NGC 1614 with thermal-IR IFU observations. The ring's characteristics and
relation to the strong star-forming ring detected in recombination lines are
presented, as well as a scenario of an outward expanding starburst likely
initiated with a (minor) companion detected within a tidal feature. We then
present NIR IFU observations of IRAS 19115-2124, aka the Bird, which is an
intriguing triple encounter. The third component is a minor one, but,
nevertheless, is the source of 3/4 of the SFR of the whole system. Gas inflows
and outflows are detected at the locations of the nuclei. Finally, we briefly
report on our on-going NIR adaptive optics imaging survey of several dozen
LIRGs. We have detected highly obscured core-collapse SNe in the central kpc,
and discuss the statistics of "missing SNe" due to dust extinction. We are also
determining the characteristics of hundreds of super star clusters in and
around the core regions of LIRGs, as a function of host-galaxy properties.
