A multi-wavelength view of the central kiloparsec region in the Luminous
  Infrared Galaxy NGC1614
  The Luminous Infrared Galaxy NGC1614 hosts a prominent circumnuclear ring of
star formation. However, the nature of the dominant emitting mechanism in its
central ~100 pc is still under debate. We present sub-arcsecond angular
resolution radio, mid-infrared, Pa-alpha, optical, and X-ray observations of
NGC1614, aimed at studying in detail both the circumnuclear ring and the
nuclear region. The 8.4 GHz continuum emission traced by the Very Large Array
(VLA) and the Gemini/T-ReCS 8.7 micron emission, as well as the Pa-alpha line
emission, show remarkable morphological similarities within the star-forming
ring, suggesting that the underlying emission mechanisms are tightly related.
We used an HST/NICMOS Pa-alpha map of similar resolution to our radio maps to
disentangle the thermal free-free and non-thermal synchrotron radio emission,
from which we obtained the intrinsic synchrotron power-law for each individual
region within the central kpc of NGC1614. The radio ring surrounds a relatively
faint, steep-spectrum source at the very center of the galaxy, suggesting that
the central source is not powered by an AGN, but rather by a compact (r < 90
pc) starburst. Chandra X-ray data also show that the central kpc region is
dominated by starburst activity, without requiring the existence of an AGN. We
also used publicly available infrared data to model-fit the spectral energy
distribution of both the starburst ring and a putative AGN in NGC1614. In
summary, we conclude that there is no need to invoke an AGN to explain the
observed bolometric properties of the galaxy.
