Uncovering the Intrinsic Variability of Gamma-Ray Bursts

Golkhou, V. Z.; Butler, Nathaniel R.

doi:10.1088/0004-637x/787/1/90

Cited by 74 publications

(75 citation statements)

References 57 publications

(90 reference statements)

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“…While in many works it is assumed that r 0 is ≈ few gravitational radii, in fact there is no evidence for that in the data; the shortest variability time scale observed in GRBs, δt = r 0 /c > ∼ 10 ms, with average value of ≈ 500 ms. 208 These results are therefore consistent with the results obtained by analyzing the thermal data.…”

Section: Probing Outflow Dynamicssupporting

confidence: 89%

Photospheric emission in gamma-ray bursts

Pe’er

Ryde

2017

Int. J. Mod. Phys. D

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A major breakthrough in our understanding of gamma-ray bursts (GRB) prompt emission physics occurred in the last few years, with the realization that a thermal component accompanies the over-all non-thermal prompt spectra. This thermal part is important by itself, as it provides direct probe of the physics in the innermost outflow regions. It further has an indirect importance, as a source of seed photons for inverse-Compton scattering, thereby it contributs to the non-thermal part as well. In this short review, we highlight some key recent developments. Observationally, although so far it was clearly identified only in a minority of bursts, there are indirect evidence that thermal component exists in a very large fraction of GRBs, possibly close to 100%. Theoretically, the existence of thermal component have a large number of implications as a probe of underlying GRB physics. Some surprising implications include its use as a probe of the jet dynamics, geometry and magnetization.

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Section: Probing Outflow Dynamicssupporting

confidence: 89%

Photospheric emission in gamma-ray bursts

Pe’er

Ryde

2017

Int. J. Mod. Phys. D

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“…12). 88,[208][209][210] While in many works it is assumed that r 0 is ≈ few gravitational radii, in fact, there is no evidence for that in the data; the shortest variability time scale observed in GRBs, δt = r 0 /c > ∼ 10 ms, with average value of ≈ 500 ms. 211 These results are therefore consistent with the results obtained by analyzing the thermal data.…”

Section: Probing Outflow Dynamicssupporting

confidence: 89%

Photospheric emission in gamma-ray bursts

Pe’er

Ryde

2017

The Fourteenth Marcel Grossmann Meeting

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A major breakthrough in our understanding of gamma-ray bursts (GRB) prompt emission physics occurred in the last few years, with the realization that a thermal component accompanies the over-all nonthermal prompt spectra. This thermal part is important by itself, as it provides direct probe of the physics in the innermost outflow regions. It further has an indirect importance, as a source of seed photons for inverse-Compton scattering, thereby it contributes to the nonthermal part as well. In this short review, we highlight some key recent developments. Observationally, although so far it was clearly identified only in a minority of bursts, there is indirect evidence that a thermal component exists in a very large fraction of GRBs, possibly close to 100%. Theoretically, the existence of a thermal component has a large number of implications as a probe of underlying GRB physics. Some surprising implications include its use as a probe of the jet dynamics, geometry and magnetization.

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“…An average value of r 0 ∼ 10 8 cm corresponds to variability time δt = r 0 /c ∼ 3 ms, fully consistent with the observed variability ≥ 10 ms (with average value ≈ 500 ms, 25 ) seen in GRBs . However, this value is ≈ 30 times greater than the gravitational radii of 10M black hole.…”

Section: Hydrodynamic Properties Of Grb Outflowssupporting

confidence: 85%

Energy dissipation below gamma-ray bursts photosphere: Evidence and spectral fits

Pe’er¹

2017

The Fourteenth Marcel Grossmann Meeting

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It is now established that a thermal emission component plays a major role in shaping the prompt spectra of a non-negligible fraction of gamma-ray bursts (GRBs). By studying the properties of this component in a sample of 47 GRBs, we deduce that the Lorentz factor is 10 2 Γ 10 3 , with mean value Γ 370. The acceleration radius r 0 span a wide range, 10 6.5 r 0 10 9.5 cm, with mean value r 0 10 8 cm. This is higher than the gravitational radius of 10 M black hole by a factor of ≈ 30. We argue that this result provides an indirect evidence for jet propagation inside a massive star, and suggests the existence of recollimation shocks that take place at this radius. We further show that sub-photospheric dissipation of the jet kinetic energy provides a self-consistent, fully physically motivated model that can fit a wide range of GRB spectra. The leading radiative process is Comptonization of the thermal component, and synchrotron emission is sub-dominant. We create a DREAM (Dissipation with Radiative Emission as a Table Model) table model for XSPEC, and show how this model can describe different types of GRB spectra.

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Uncovering the Intrinsic Variability of Gamma-Ray Bursts

Cited by 74 publications

References 57 publications

Photospheric emission in gamma-ray bursts

Photospheric emission in gamma-ray bursts

Photospheric emission in gamma-ray bursts

Energy dissipation below gamma-ray bursts photosphere: Evidence and spectral fits

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