  We report the results of our ongoing search for extincted supernovae (SNe) at
near-infrared wavelengths. We have monitored at 2.2 micron a sample of 46
Luminous Infrared Galaxies and detected 4 SNe. The number of detections is
still small but sufficient to provide the first estimate of supernova rate at
near-infrared wavelengths. We measure a SN rate ofv 7.6+/-3.8 SNu which is an
order of magnitude larger than observed in quiescent galaxies. On the other
hand, the observed near-infrared rate is still a factor 3-10 smaller than that
estimated from the far-infrared luminosity of the galaxies. Among various
possibilities, the most likely scenario is that dust extinction is so high
(Av>30) to obscure most SNe even in the near-IR.
  The role of type Ia SNe is also discussed within this context. We derive the
type Ia SN rate as a function of the stellar mass of the galaxy and find a
sharp increase toward galaxies with higher activity of star formation. This
suggests that a significant fraction of type Ia SNe are associated with young
stellar populations.
  Finally, as a by-product, we give the average K-band light curve of
core-collapse SNe based on all the existing data, and review the relation
between SN rate and far-infrared luminosity.

Astrophysics