The connection between gamma-ray bursts and supernovae Ib/c

¹ Dipartimento di Fisica, Universitá di Trieste, via Valerio 2, 34127, Trieste, Italy e-mail: ebs@mpe.mpg.de
² INAF – Osservatorio Astronomico di Trieste, via G. B. Tiepolo 11, 34131 Trieste, Italy
³ Dipartimento di Astronomia – Universitá di Trieste, via G. B. Tiepolo 11, 34131 Trieste, Italy
⁴ INFN, Sezione di Trieste, via Valerio 2, 34127 Trieste, Italy

Received: 15 November 2006
Accepted: 21 February 2007

Abstract

Context.It has been established that Gamma-Ray Bursts (GRBs) are connected to Supernovae (SNe) explosions of type Ib/c.

Aims.We intend to test whether the hypothesis of type Ib/c SNe from different massive progenitors can reproduce the local GRB rate as well as the GRB rate as a function of redshift. We aim to predict the GRB rate at very high redshift under different assumptions about galaxy formation and star formation histories in galaxies.

Methods.We assume different star formation histories in galaxies of different morphological types: ellipticals, spirals and irregulars, which have already been tested in self-consistent galaxy models reproducing both chemical and photometrical properties of galaxies. We explore different hypotheses concerning the progenitors of type Ib/c SNe: i) single massive stars (, Wolf-Rayet stars), ii) massive close binaries (12–20 ), and iii) both Wolf-Rayet stars and massive binaries. We conclude that the mixed scenario (iii) is preferable to reproduce the local type Ib/c SN rates in galaxies and we adopt this scenario for comparison with the GRB rates.

Results.We find an excellent agreement between the observed GRB local rate and the predicted type Ib/c SN rate in irregular galaxies, when a range for single Wolf-Rayet stars of 40–100  is adopted. We also predict the cosmic type Ib/c SN rate by taking into account all the galaxy types in a unitary volume of the Universe and we compare it with the observed cosmic GRB rate as a function of redshift. By assuming the formation of spheroids at high redshift, we predict a cosmic type Ib/c SN rate, which is always higher than the GRB rate, suggesting that only a small fraction (0.1–1%) of type Ib/c SNe become GRBs. In particular, we find a ratio between the cosmic GRB rate and the cosmic type Ib/c rate in the range –, in agreement with previous estimates. Finally, due to the high rate of star formation in spheroids at high redshift, which is our preferred scenario for galaxy formation, we predict more GRBs at high redshift than in the hierarchical scenario for galaxy formation, a prediction which remains to be proven by future observations.