Spectral and Polarization Properties of Photospheric Emission From Stratified Jets

Abstract

We explore the spectral and polarization properties of photospheric emissions from stratified jets in which multiple components, separated by a sharp velocity shear regions, are distributed in lateral direction. Propagation of thermal photons injected at high optical depth region are calculated until they escape from the photosphere. It is found that presence of the lateral structure within the jet leads to non-thermal feature of the spectra and significant polarization signal in the resulting emission. The deviation from thermal spectra as well as the polarization degree tends to be enhanced as the velocity gradient in the shear region increases. In particular, we show that emissions from multi-component jet can reproduce the typical observed spectra of gamma-ray bursts (GRBs) irrespective to the position of the observer when a velocity shear region is closely spaced in various lateral ($\theta$) positions. The degree of polarization associated in the emission is significant (> few%) at wide range of observer angles and can be higher than 30%.

21 pages, 12 figures, accepted for publication in ApJ

References in corpus (12)

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• Prompt GRB emission from gradual energy dissipation
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• Polarization in the prompt emission of gamma-ray bursts and their afterglows
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• Monte Carlo simulations of the photospheric emission in GRBs

Cited by in corpus (15)

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• Closure relations during the plateau emission of Swift GRBs and the fundamental plane
• Linear Theory of the Rayleigh-Taylor Instability at a Discontinuous Surface of a Relativistic Flow
• Time-Resolved and Energy-Resolved Polarizations of GRB Prompt Emission
• A global numerical model of the prompt emission in short gamma-ray bursts
• Accounting for Selection Bias and Redshift Evolution in GRB Radio Afterglow Data
• Temporal Evolution of Prompt GRB Polarization
• A Monte Carlo Radiation Transfer Study of Photospheric Emission in Gamma Ray Bursts
• Photospheric Polarization Signatures From Long Gamma Ray Burst Simulations
• Photospheric Prompt Emission From Long Gamma Ray Burst Simulations -- II. Spectropolarimetry
• Time-averaging Polarimetric and Spectral Properties of Gamma-Ray Bursts
• Adding Gamma-ray Polarimetry to the Multi-Messenger Era
• Validation of Radiative Transfer Computation with Monte Carlo Method for Ultra-Relativistic Background Flow
• Modeling of the Gamma Ray Burst photospheric emission: Monte Carlo simulation of the GRB prompt emission, numerical results and discussion