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Title: The Role of a Neutron Component in the Photospheric Emission of Long-duration Gamma-Ray Burst Jets
Abstract Long-duration gamma-ray bursts (LGRBs), thought to be produced during core-collapse supernovae, may have a prominent neutron component in the outflow material. If present, neutrons can change how photons scatter in the outflow by reducing its opacity, thereby allowing the photons to decouple sooner than if there were no neutrons present. Understanding the details of this process could therefore allow us to probe the central engine of LGRBs, which is otherwise hidden. Here, we present results of the photospheric emission from an LGRB jet, using a combination of relativistic hydrodynamic simulations and radiative transfer postprocessing using Monte Carlo radiation transfer code. We control the size of the neutron component in the jet material by varying the equilibrium electron fractionYe, and we find that the presence of neutrons in the GRB fireball affects the Band parametersαandE0, while the picture with theβparameter is less clear. In particular, the break energyE0is shifted to higher energies. Additionally, we find that increasing the size of the neutron component also increases the total radiated energy of the outflow across multiple viewing angles. Our results not only shed light on LGRBs but are also relevant to short-duration gamma-ray bursts associated with binary neutron star mergers due to the likelihood of a prominent neutron component in such systems.  more » « less
Award ID(s):
1907955
PAR ID:
10566995
Author(s) / Creator(s):
; ;
Publisher / Repository:
IoP
Date Published:
Journal Name:
The Astrophysical Journal
Volume:
965
Issue:
1
ISSN:
0004-637X
Page Range / eLocation ID:
8
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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