The infrared supernova rate in starburst galaxies ^*

¹ Istituto di Radioastronomia, sezione di Firenze, Largo E. Fermi 5, 50125, Firenze, Italy e-mail: filippo@arcetri.astro.it
² INAF, Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy
³ Dipartimento di Astronomia, Univesità di Roma, via della vasca navale 86, Roma, Italy
⁴ Dipartimento di astronomia, Università di Firenze, Largo E. Fermi 5, 50125, Firenze, Italy
⁵ ESO, Ave. Alonso de Cordova 3107, Casilla 19, Santiago 19001, Chile
⁶ Telescopio Nazionale Galileo, Aptdo de Correos 565, 38700 Santa Cruz de la Palma, Canary Island, Spain
⁷ Steward Observatory, Univ. of Arizona, Tucson, AZ85721, USA

Corresponding author: F. Mannucci, filippo@arcetri.astro.it

Received: 13 November 2002
Accepted: 13 February 2003

Abstract

We report the results of our ongoing search for extincted supernovae (SNe) at near-infrared wavelengths. We have monitored at 2.2 μm 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 of  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 () 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.