  We present a study of the central 2.3 kpc of NGC 5135, a nearby Luminous
Infrared Galaxy (LIRG) with an AGN and circumnuclear starburst. Our main
results are based on intermediate spectral resolution (~ 3000-4000) near
infrared data taken with the SINFONI integral field spectrograph at the ESO
VLT. The ionization of the different phases of the interstellar gas and the
complex structures of the star formation have been mapped. Individual regions
of interest have been identified and studied in detail.
  For the first time in this galaxy, we have detected the presence of a high
excitation ionization cone centered on the AGN by using the [SiVI] (1.96
micron) line. So far, this structure is the largest reported in the literature
for this coronal line, extending (in projection) as far as ~ 600 pc from the
galaxy nucleus. In a complex spatial distribution, a variety of mechanisms are
driving the gas ionization, including SNe remnant shocks, young stars and AGN
photoionization. The excitation of the molecular gas, however, is mainly
produced by X-rays and SNe remnant shocks. UV-mechanisms like fluorescence
represent a marginal overall contribution to this process, contrary to the
expectations we might have for a galaxy with a recent and strong star
formation. Our SNe rate estimations from [FeII] (1.64 micron) are in excellent
agreement with 6 cm radio emission predictions. Typical SNe rates between
0.01-0.04 yr^-1 were found for individual ~ 200 pc-scale regions, with an
overall SNe rate of 0.4-0.5 yr^-1. Even though NGC 5135 has suffered a recent
starburst (6-7 Myr ago), the data strongly suggest the presence of a second,
older stellar population dominated by red giant/supergiant stars.
