Astronomy and Astrophysics – Astrophysics
Scientific paper
2006-12-07
Astrophys.J.Lett.657:L73-L76,2007
Astronomy and Astrophysics
Astrophysics
13 pages, 2 figures, ApJ Letters in press
Scientific paper
10.1086/511417
We measure the local rates of ``low-luminosity'' (LL-GRBs, i.e. L<10^{48--49}erg/sec) and ``high-luminosity'' Gamma-ray Bursts (HL-GRBs). The values are in the range n0=100--1800 Gpc^(-3)yr^(-1) and n0=100--550 Gpc^(-3) yr^(-1), respectively, and the ratios to SNe-Ibc \sim 1%-9% and 0.4% -3%. These data may suggest the existence of two physically distinct classes of GRBs in which LL-GRBs are (intrinsically) more frequent events than HL-GRBs. However, with the present data we cannot exclude the possibility of a single population of GRBs which give rise to both an isotropic low-luminous emission (LL-GRBs: detectable only in nearby GRBs) and to a highly collimated high-luminous emission (HL-GRBs: detectable preferentially at high-z). We compute also the rate of SNe-Ibc characterized by broad-lined spectra (Hypernovae) and found it to be about 1.5\times 10^(-4)HNe yr^(-1) 10^(10) L_(B\odot) (i.e less than 10% of SNe-Ibc occurring in Spirals). This result implies that the ratio HL-GRBs/HNe is smaller than 1, possibly in the range 0.04--0.3. We have used the ratio between Hypernovae and LL-GRBs to constrain their beaming factor to f_b^(-1)\sim 10 or less.
Della Valle Massimo
Guetta Dafne
No associations
LandOfFree
On the Rates of Gamma Ray Bursts and Type Ib/c Supernovae does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with On the Rates of Gamma Ray Bursts and Type Ib/c Supernovae, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On the Rates of Gamma Ray Bursts and Type Ib/c Supernovae will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-571905