Death rate of massive stars at redshift 0.3 ^*

¹ INAF - Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, 80131 Napoli, Italy e-mail: cappellaro@na.astro.it
² European Southern Observatory, K. Schwarzschild Str. 2, 85748 Garching, Germany
³ INAF - Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122 Padova, Italy
⁴ Dipartimento di Astronomia - Universitá di Padova, Vicolo dell'Osservatorio 2, 35122 Padova, Italy
⁵ Departament d'Astronomia i Meteorologia, Universitat de Barcelona, Martí i Franqués 1, 08028 Barcelona, Spain
⁶ Osservatorio Astronomico di Collurania, via M. Maggini, 64100 Teramo, Italy Dipartimento di Scienze della Comunicazione, Universitá di Teramo, viale Crucioli 122, 64100 Teramo, Italy
⁷ Departamento de Astronomía y Astrofísica, Pontificia Universidad Católica, Chile
⁸ INAF - Osservatorio Astronomico di Trieste, via Tiepolo 11, 34131 Trieste, Italy
⁹ INAF - Osservatorio Astronomico di Arcetri, Largo E. Fermi 5, 50125 Firenze, Italy
¹⁰ Australian National University, Mount Stromlo Observatory, Cotter Road, Weston ACT 2611, Australia
¹¹ Dipartimento di Fisica - Universitá di Ferrara, via del Paradiso 12, 44100 Ferrara, Italy

Received: 7 May 2004
Accepted: 8 September 2004

Abstract

We report the first result of a supernova search program designed to measure the evolution of the supernova rate with redshift. To make the comparison with local rates more significant we copied, as much as possible, the same computation recipes as for the measurements of local rates. Moreover, we exploited the multicolor images and the photometric redshift technique to characterize the galaxy sample and accurately estimate the detection efficiency.
Combining our data with the recently published measurements of the SN Ia rate at different redshifts, we derived the first, direct measurement of the core collapse supernova rate at  as  SNu [ /75] . This is a factor of three (±50%) larger than the local estimate. The increase for a look back time of 2.8 Gyr is more rapid than predicted by most of the published models of SN rate evolution. Core-collapse SN rates measure the death rate of massive stars and, because of the short time scale of evolution, can be translated into a measurement of the ongoing SFR. Assuming a Salpeter IMF and the standard scenario for core-collapse progenitors we derived an estimate of the star formation rate at redshift  which compares very well with a recent estimate based on the measurement of the Hα luminosity density at the same redshift.