Photospheric Emission from Collapsar Jets in 3D Relativistic Hydrodynamics

TL;DR

This study uses 3D relativistic hydrodynamical simulations to analyze how jet dynamics and precession influence photospheric emission in collapsar models, revealing observable signatures and non-thermal spectral features relevant to gamma-ray bursts.

Contribution

It introduces detailed 3D simulations of jet-envelope interactions and precession effects, showing their impact on emission signatures and spectral features in collapsar jets.

Findings

Precession signatures are observable in light curves.

Jet-envelope interactions significantly shape emission.

Non-thermal spectral features can arise from thermal photon injection.

Abstract

We explore the photospheric emission from a relativistic jet breaking out from a massive stellar envelope based on relativistic hydrodynamical simulations and post-process radiation transfer calculations in three dimensions. To investigate the impact of three-dimensional (3D) dynamics on the emission, two models of injection conditions are considered for the jet at the center of the progenitor star: one with periodic precession and another without precession. We show that structures developed within the jet due to the interaction with the stellar envelope, as well as due to the precession, have a significant imprint on the resulting emission. Particularly, we find that the signature of precession activity by the central engine is not smeared out and can be directly observed in the light curve as a periodic signal. We also show non-thermal features, which can account for observations of gamma-ray bursts, are produced in the resulting spectra, even though only thermal photons are injected initially and the effect of non-thermal particles is not considered.