  (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.
