38 research outputs found
Theoretical interpretation of GRB 011121
GRB011121 is analyzed as a prototype to understand the ``flares'' recently
observed by Swift in the afterglow of many GRB sources. Detailed theoretical
computation of the GRB011121 light curves in selected energy bands are
presented and compared and contrasted with observational BeppoSAX data.Comment: 2 pages, 1 figure, to appear in the proceedings of "Swift and GRBs",
Venice, 2006, Il Nuovo Cimento, in pres
GRB970228 as a prototype for short GRBs with afterglow
GRB970228 is analyzed as a prototype to understand the relative role of short
GRBs and their associated afterglows, recently observed by Swift and HETE-II.
Detailed theoretical computation of the GRB970228 light curves in selected
energy bands are presented and compared with observational BeppoSAX data.Comment: 2 pages, 1 figure, to appear in the proceedings of "Swift and GRBs",
Venice, 2006, Il Nuovo Cimento, in pres
Theoretical interpretation of GRB060124: preliminary results
We show the preliminary results of the application of our "fireshell" model
to GRB060124. This source is very peculiar because it is the first event for
which both the prompt and the afterglow emission were observed simultaneously
by the three Swift instruments: BAT (15-350 keV), XRT (0.2-10 keV) and UVOT
(170-650 nm), due to the presence of a precursor ~ 570 s before the main burst.
We analyze GRB060124 within our "canonical" GRB scenario, identifying the
precursor with the P-GRB and the prompt emission with the afterglow peak
emission. In this way we reproduce correctly the energetics of both these two
components. We reproduce also the observed time delay between the precursor
(P-GRB) and the main burst. The effect of such a time delay in our model will
be discussed.Comment: 6 pages, 2 figures, to appear on the Proceedings of the Eleventh
Marcel Grossmann Meeting, Berlin (Germany), July 200
The Blackholic energy and the canonical Gamma-Ray Burst
We outline the main results of our GRB model, based on the three
interpretation paradigms we proposed in July 2001, comparing and contrasting
them with the ones in the current literature. Thanks to the observations by
Swift and by VLT, this analysis points to a "canonical GRB" originating from
markedly different astrophysical scenarios. The communality is that they are
all emitted in the formation of a black hole with small or null angular
momentum. The following sequence appears to be canonical: the vacuum
polarization process creating an optically thick self accelerating
electron-positron plasma; the engulfment of baryonic mass during the plasma
expansion; the adiabatic expansion of the optically thick "fireshell" up to the
transparency; the interaction of the remaining accelerated baryons with the
interstellar medium (ISM). This leads to the canonical GRB composed of a proper
GRB (P-GRB), emitted at the moment of transparency, followed by an extended
afterglow. The parameters are the plasma total energy, the fireshell baryon
loading and the ISM filamentary distribution around the source. In the limit of
no baryon loading the total energy is radiated in the P-GRB. In this limit, the
canonical GRBs explain as well the short GRBs.Comment: 163 pages, 89 figures, to appear on the "Proceedings of the XIIth
Brazilian School of Cosmology and Gravitation", M. Novello, S.E.
Perez-Bergliaffa (editors), AIP, in pres
Short and canonical GRBs
Within the "fireshell" model for the Gamma-Ray Bursts (GRBs) we define a
"canonical GRB" light curve with two sharply different components: the
Proper-GRB (P-GRB), emitted when the optically thick fireshell of
electron-positron plasma originating the phenomenon reaches transparency, and
the afterglow, emitted due to the collision between the remaining optically
thin fireshell and the CircumBurst Medium (CBM). We outline our "canonical GRB"
scenario, with a special emphasis on the discrimination between "genuine" and
"fake" short GRBs.Comment: 4 pages, 3 figures, in the Proceedings of the "Gamma Ray Bursts 2007"
meeting, November 5-9, 2007, Santa Fe, New Mexico, US
Theoretical interpretation of "long" and "short" GRBs
Within the "fireshell" model we define a "canonical GRB" light curve with two
sharply different components: the Proper-GRB (P-GRB), emitted when the
optically thick fireshell of electron-positron plasma originating the
phenomenon reaches transparency, and the afterglow, emitted due to the
collision between the remaining optically thin fireshell and the CircumBurst
Medium (CBM). We here present the consequences of such a scenario on the
theoretical interpretation of the nature of "long" and "short" GRBs.Comment: 3 pages, 1 figure, to appear on the Proceedings of the Eleventh
Marcel Grossmann Meeting, Berlin (Germany), July 200
The Blackholic energy and the canonical Gamma-Ray Burst IV: the "long", "genuine short" and "fake - disguised short" GRBs
(Shortened) [...] After recalling the basic features of the "fireshell
model", we emphasize the following novel results: 1) the interpretation of the
X-ray flares in GRB afterglows as due to the interaction of the optically thin
fireshell with isolated clouds in the CircumBurst Medium (CBM); 2) an
interpretation as "fake - disguised" short GRBs of the GRBs belonging to the
class identified by Norris & Bonnell [...] consistent with an origin from the
final coalescence of a binary system in the halo of their host galaxies with
particularly low CBM density [...]; 3) the first attempt to study a genuine
short GRB with the analysis of GRB 050509B, that reveals indeed still an open
question; 4) the interpretation of the GRB-SN association in the case of GRB
060218 via the "induced gravitational collapse" process; 5) a first attempt to
understand the nature of the "Amati relation", a phenomenological correlation
between the isotropic-equivalent radiated energy of the prompt emission E_{iso}
with the cosmological rest-frame \nu F_{\nu} spectrum peak energy E_{p,i}. In
addition, recent progress on the thermalization of the electron-positron plasma
close to their formation phase, as well as the structure of the electrodynamics
of Kerr-Newman Black Holes are presented. An outlook for possible explanation
of high-energy phenomena in GRBs to be expected from the AGILE and the Fermi
satellites are discussed. As an example of high energy process, the work by
Enrico Fermi dealing with ultrarelativistic collisions is examined. It is clear
that all the GRB physics points to the existence of overcritical
electrodynamical fields. In this sense we present some progresses on a unified
approach to heavy nuclei and neutron stars cores, which leads to the existence
of overcritical fields under the neutron star crust.Comment: 68 pages, 50 figures, in the Proceedings of the XIII Brazilian School
on Cosmology and Gravitation, M. Novello, S.E. Perez-Bergliaffa, editor
The canonical Gamma-Ray Bursts and their "precursors"
The fireshell model for Gamma-Ray Bursts (GRBs) naturally leads to a
canonical GRB composed of a proper-GRB (P-GRB) and an afterglow. P-GRBs,
introduced by us in 2001, are sometimes considered "precursors" of the main GRB
event in the current literature. We show in this paper how the fireshell model
leads to the understanding of the structure of GRBs, with precise estimates of
the time sequence and intensities of the P-GRB and the of the afterglow. It
leads as well to a natural classification of the canonical GRBs which overcomes
the traditional one in short and long GRBs.Comment: 4 pages, 3 figures, Proceedings of the 2008 Nanjing GRB conferenc