Dainotti 2007 GRB 060218 and binary model

主要内容:
Observation summarized first, then pointed out that: collapse of NS in a binary system can give this low energetic thing.

精彩摘抄:


文章信息:

arXiv:0712.0567 [ps, pdf, other]

Title: GRB 060218 and the binaries as progenitors of GRB-SN systems

Authors: Maria Giovanna Dainotti, Maria Grazia Bernardini, Carlo Luciano Bianco, Letizia Caito, Roberto Guida, Remo Ruffini

Comments: 6 pages, 3 figures, in the Proceedings of the "4th Italian-Sino Workshop on Relativistic Astrophysics", held in Pescara, Italy, July 20-28, 2007, C.L. Bianco, S.-S. Xue, Editors

Journal-ref: AIP Conf.Proc. 966 (2007) 25-30

Subjects: Astrophysics (astro-ph)

(shortened) We study the Gamma-Ray Burst (GRB) 060218: a particularly close source at z=0.033 with an extremely long duration, namely T_{90} ~ 2000 s, related to SN 2006aj. [...] I present the fitting time consuming procedure. In order to show its sensitivity I also present two examples of fits with the same value of B and different value of E_{e^\pm}^{tot}. We fit the X- and \gamma-ray observations by Swift of GRB 060218 in the 0.1-150 keV energy band during the entire time of observations from 0 all the way to 10^6 s within a unified theoretical model. The free parameters of our theory are only three, namely the total energy E_{e\pm}^{tot} of the e^\pm plasma, its baryon loading B \equiv M_Bc^2/E_{e\pm}^{tot}, as well as the CircumBurst Medium (CBM) distribution. We justify the extremely long duration of this GRB by a total energy E_{e\pm}^{tot} = 2.32\times 10^{50} erg, a very high value of the baryon loading B=1.0\times 10^{-2} and the effective CircumBurst Medium (CBM) density which shows a radial dependence n_{cbm} \propto r^{-\alpha} with 1.0 \leq \alpha \leq 1.7 and monotonically decreases from 1 to $10^{-6}$ particles/cm$^3$. We recall that this value of the $B$ parameter is the highest among the sources we have analyzed and it is very close to its absolute upper limit expected. [...] We also think that the smallest possible black hole, formed by the gravitational collapse of a neutron star in a binary system, is consistent with the especially low energetics of the class of GRBs associated with SNe Ib/c.