University of Leicester
2023MeredithTPhD.pdf (13.46 MB)

Magnetar Driven Emission in Short Gamma-Ray Bursts

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posted on 2023-09-28, 15:35 authored by Tomos R. L. Meredith

Gamma-ray bursts (GRBs) are the brightest astrophysical phenomena in the Universe. The "short" type of GRBs (typically having most of their emission occur over a timescales of less than two seconds) are now widely held to be produced by the merger of a binary neutron star system, though this hypothesis faces a challenge explaining the existence of persistent late-time emission in a subset of short GRBs, referred to as extended emission. An increasingly popular proposal for modelling extended emission is the production of a remnant magnetar from the merger, whose magnetic field, and its interaction with surrounding merger ejecta, powers the late-time luminosity profile. This magnetic propeller model has generally fared well in reproducing long-lasting emission for short GRBs, but has shown itself to have difficulty capturing rapid, late-time flare-like features in the light-curve effectively.

This thesis attempts to improve the way in which the magnetic propeller model fits to rapidly-varying observational data. I adopt a two-pronged approach in this endeavour. First, I examine the data processing algorithm commonly used for producing the observational data to which the magnetic propeller model is fit, in order to establish the robustness of the features in the light-curve. In this way, I can evaluate how significant these features are, and the importance of fitting to them. Second, I refine the physical model by adding additional, physically justifiable components aimed at capturing flaring behaviour which does exist within the observational data. This work enhances both the versatility of the magnetic propeller model for short GRBs with extended emission, and the robustness of the observational data to which the physical model is fit.



Phil Evans

Date of award


Author affiliation

School of Physics & Astronomy

Awarding institution

University of Leicester

Qualification level

  • Doctoral

Qualification name

  • PhD



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