Radiation diffusion in a ultra-relativistic expanding shell in relation to gamma-ray bursts

The present-day observational data obtained by satellite observatories cover seven decades of gamma-ray energy, and there is no universal general model describing the formation of the spectrum. Therefore, it is important to describe the initial stages of radiation propagation in an ultrarelativistically expanding shell. The aim of this study was to obtain equations describing the propagation of radiation in a relativistically expanding shell in the diffusion limit, solve them for natural initial data, and apply the results obtained to the initial radiation of gamma-ray bursts. The following results were obtained: the initial stage of the gamma-ray burst in a photon-thin case can be described by radiation diffusion in an ultrarelativistically expanding shell; the time interval at which it is still possible to use the diffusion approximation increases with increasing the depth inside the shell quadratically; the value of the depth beyond which the diffusion approximation can be used increases, and the value of the radiation intensity decreases in diffusion time approaches; during the main radiation of the photon-thin shell, the diffusion approximation is suitable for most of the jet. The parameters of emission are close to the ones of short gamma-ray bursts.

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THIN SHELL WORMHOLE DUE TO DYADOSPHERE OF A CHARGED BLACK HOLE

Modern Physics Letters A ◽

10.1142/s0217732309027406 ◽

2009 ◽

Vol 24 (01) ◽

pp. 53-61 ◽

Cited By ~ 14

Author(s):

F. RAHAMAN ◽

M. KALAM ◽

K. A. RAHMAN

Keyword(s):

Black Hole ◽

Electric Field ◽

Physical Properties ◽

Pair Production ◽

Thin Shell ◽

Gamma Ray ◽

Critical Value ◽

Gamma Ray Bursts ◽

Charged Black Hole ◽

Special Region

To explain Gamma Ray Bursts, Ruffini argued that the event horizon of a charged black hole is surrounded by a special region called, the Dyadosphere where electric field exceeds the critical value for e+e- pair production. In the present work, we construct a thin shell wormhole by performing a thought surgery between two dadospheres. Several physical properties of this thin shell wormhole have been analyzed.

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One Dimensional Hydrodynamics of Asteroid-Neutron Star Collisions

International Astronomical Union Colloquium ◽

10.1017/s0252921100082105 ◽

1980 ◽

Vol 58 ◽

pp. 591-594

Author(s):

Michael J. Newman ◽

Arthur N. Cox

Keyword(s):

Neutron Star ◽

Solid Body ◽

Gamma Ray ◽

Compact Object ◽

Gamma Ray Bursts ◽

Radiation Diffusion ◽

Gamma Ray Burst ◽

One Dimensional

It has been suggested by several authors (e.g., Harwit and Salpeter, 1973) that the observed cosmic gamma-ray bursts might be produced by the collision of comet or asteroid-sized bodies with a compact object. Colgate and Petschek (1980) have discussed the tidal breakup of a solid body approaching a neutron star in central impact, with particular application to the cosmic gamma-ray burst of March 5, 1979. In this work we present the results of simplified one-dimensional hydrodynamic-radiation diffusion calculations of such an occurence.

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A cumulative search for hard X/γ-ray emission associated with fast radio bursts in Fermi/GBM data

Astronomy and Astrophysics ◽

10.1051/0004-6361/201936284 ◽

2019 ◽

Vol 631 ◽

pp. A62 ◽

Cited By ~ 8

Author(s):

R. Martone ◽

C. Guidorzi ◽

R. Margutti ◽

L. Nicastro ◽

L. Amati ◽

...

Keyword(s):

Gamma Ray ◽

High Energy ◽

Gamma Ray Bursts ◽

Integration Time ◽

Time Interval ◽

Radio Bursts ◽

Emission Mechanism ◽

Sample Average ◽

Γ Ray ◽

The One

Context. Fast radio bursts (FRBs) are millisecond-long bursts uniquely detected at radio frequencies. FRB 131104 is the only case for which a γ-ray transient positionally and temporally consistent was claimed. This high-energy transient had a duration of ∼400 s and a 15–150 keV fluence Sγ ∼ 4 × 10−6 erg cm−2. However, the association with the FRB is still debated. Aims. We aim at testing the systematic presence of an associated transient high-energy counterpart throughout a sample of the FRB population. Methods. We used an approach like that used in machine learning methodologies to accurately model the highly-variable Fermi/GBM instrumental background on a time interval comparable to the duration of the proposed γ-ray counterpart of FRB 131104. A possible γ-ray signal is then constrained considering sample average lightcurves. Results. We constrain the fluence of the possible γ-ray signal in the 8–1000 keV band down to 6.4 × 10−7 (7.1 × 10−8) erg cm−2 for a 200-s (1-s) integration time. Furthermore, we found the radio-to-gamma fluence ratio to be η > 108 Jy ms erg−1 cm2. Conclusions. Our fluence limits exclude ∼94% of Fermi/GBM detected long gamma-ray bursts and ∼96% of Fermi/GBM detected short gamma-ray bursts. In addition, our limits on the radio-to-gamma fluence ratio point to a different emission mechanism from that of magnetar giant flares. Finally, we exclude a γ-ray counterpart as fluent as the one possibly associated with FRB 131104 to be a common feature of FRBs.

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