Monte Carlo Radiation Transfer Simulations of Photospheric Emission in Long-Duration Gamma-Ray Bursts

Lazzati, Davide

doi:10.3847/0004-637x/829/2/76

Cited by 24 publications

(33 citation statements)

References 58 publications

(123 reference statements)

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“…We note, however, that an accurate evaluation of the spectral shape requires higher spatial resolution 15,25 . Moreover, if present, non-thermal particles arising from internal dissipation 20–24 may also contribute to spectral broadening. Note that such dissipation does not affect the average energy of photons as long as the generated heat is smaller than the thermal energy.…”

Section: Resultsmentioning

confidence: 99%

“…To capture all the essential features, the calculation needs to cover a large range in time and space, and must be performed in three dimensions (3D). We have previously reported on such a calculation 15 , which was followed by another group 16–18 in 2D. However, these studies were only able to evaluate the emission at small viewing angles θ obs .…”

Section: Introductionmentioning

confidence: 99%

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The photospheric origin of the Yonetoku relation in gamma-ray bursts

et al. 2019

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Long duration gamma-ray bursts (GRBs), the brightest events since the Big Bang itself, are believed to originate in an ultra-relativistic jet breaking out from a massive stellar envelope. Despite decades of study, there is still no consensus on their emission mechanism. One unresolved question is the origin of the tight correlation between the spectral peak energy and peak luminosity discovered in observations. This Yonetoku relation is the tightest correlation found in the properties of the prompt phase of GRB emission, providing the best diagnostic for the radiation mechanism. Here we present three-dimensional hydrodynamical simulations, and post-process radiation transfer calculations, of photospheric emission from a relativistic jet. Our simulations reproduce the Yonetoku relation as a natural consequence of viewing angle. Although jet dynamics depend sensitively on luminosity, the correlation holds regardless. This result strongly suggests that photospheric emission is the dominant component in the prompt phase of GRBs.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The photospheric origin of the Yonetoku relation in gamma-ray bursts

et al. 2019

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“…Keren & Levinson (2014) have reached a similar conclusion, demonstrating that multiple RMS can naturally generate a Band-like spectrum. More recent work (Ito et al 2015;Lazzati 2016;Parsotan & Lazzati 2017) combines hydrodynamics (HD) and Monte-Carlo codes to compute the emitted spectrum. In this technique, the output of the HD simulations is used as input for the Monte-Carlo radiative transfer calculations.…”

Section: Sub-photospheric Shocks In Grbsmentioning

confidence: 99%

Monte Carlo simulations of relativistic radiation-mediated shocks – I. Photon-rich regime

Ito

Levinson

Stern

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We explore the physics of relativistic radiation mediated shocks (RRMSs) in the regime where photon advection dominates over photon generation. For this purpose, a novel iterative method for deriving a self-consistent steady-state structure of RRMS is developed, based on a Monte-Carlo code that solves the transfer of photons subject to Compton scattering and pair production/annihilation. Systematic study is performed by imposing various upstream conditions which are characterized by the following three parameters: the photon-to-baryon inertia ratio ξ u * , the photon-to-baryon number ratioñ, and the shock Lorentz factor γ u . We find that the properties of RRMSs vary considerably with these parameters. In particular, while a smooth decline in the velocity, accompanied by a gradual temperature increase is seen for ξ u * ≫ 1, an efficient bulk Comptonization, that leads to a heating precursor, is found for ξ u * 1. As a consequence, although particle acceleration is highly inefficient in these shocks, a broad non-thermal spectrum is produced in the latter case. The generation of high energy photons through bulk Comptonization leads, in certain cases, to a copious production of pairs that provide the dominant opacity for Compton scattering. We also find that for certain upstream conditions a weak subshock appears within the flow. For a choice of parameters suitable to gamma-ray bursts, the radiation spectrum within the shock is found to be compatible with that of the prompt emission, suggesting that subphotospheric shocks may give rise to the observed non-thermal features despite the absence of accelerated particles.

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“…Such calculations have only been carried so far in the context of photospheric models without energy dissipation close to the photosphere (Ito et al 2015;Lazzati 2016). This requires a more involved calculation and is beyond the scope of the current work, in which we aim to highlight the qualitative features of the model at hand.…”

Section: Radiationmentioning

confidence: 99%

Prompt gamma-ray burst emission from gradual magnetic dissipation

Beniamini

Giannios

2017

Monthly Notices of the Royal Astronomical Society

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We considered a model for the prompt phase of Gamma-Ray Burst (GRB) emission arising from a magnetized jet undergoing gradual energy dissipation due to magnetic reconnection. The dissipated magnetic energy is translated to bulk kinetic energy and to acceleration of particles. The energy in these particles is released via synchrotron radiation as they gyrate around the strong magnetic fields in the jet. At small radii, the optical depth is large, and the radiation is reprocessed through Comptonization into a narrow, strongly peaked, component. At larger distances the optical depth becomes small and radiation escapes the jet with a non-thermal distribution. The obtained spectra typically peak around ≈ 300keV (as observed) and with spectral indices below and above the peak that are, for a broad range of the model parameters, close to the observed values. The small radius of dissipation causes the emission to become self absorbed at a few keV and can sufficiently suppress the optical and X-ray fluxes within the limits required by observations (Beniamini & Piran 2014).

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Monte Carlo Radiation Transfer Simulations of Photospheric Emission in Long-Duration Gamma-Ray Bursts

Cited by 24 publications

References 58 publications

The photospheric origin of the Yonetoku relation in gamma-ray bursts

The photospheric origin of the Yonetoku relation in gamma-ray bursts

Monte Carlo simulations of relativistic radiation-mediated shocks – I. Photon-rich regime

Prompt gamma-ray burst emission from gradual magnetic dissipation

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