Honors Theses and Capstones

Date of Award

Spring 2019

Project Type

Senior Honors Thesis

College or School

CEPS

Department

Physics

Program or Major

Physics

Degree Name

Bachelor of Science

First Advisor

Francois Foucart

Second Advisor

Harald Kucharek

Abstract

In 2017, LIGO detected gravitational waves from GW170817. This presented for the first time, gravitational waves originating from a neutron star - neutron star merger. Studies of neutron star mergers are significant because the multi-messenger signals in the form of gravitational waves and electromagnetic waves can inform us on the nuclear physics of neutron stars and the creation of heavy elements in the universe. Matter is ejected in the merging process and forms the outflow which provides a neutron-rich environment for rapid neutron capture (r-process) to occur leading to the nucleosynthesis of heavy elements. What we detect on Earth are kilonova emissions powered by the radioactive decays of these heavy, unstable elements. Therefore, simulations that accurately model the time evolution of matter outflows are needed to study neutron star mergers. In this study I have performed a simulation of a binary neutron star merger using the SpEC-Hydro code. The merger system consists of a 1.2M and 1.4M neutron star which are counter-rotating with respect to one another. With data from the simulation, I used classical mechanics (accounting for relativistic corrections) to recreate the time evolution of particle trajectories in order to model the matter density distribution at any arbitrary time. This method is not limited to binary neutron star mergers and can be applied to any generic merger system. I will also be covering the work I have done in [1] regarding neutrino transport schemes. We used a Monte-Carlo (MC) algorithm to analytically solve Boltzmann's equations of radiation transport. I analyzed the neutrinos emitted by a binary neutron star merger remnant and compared the neutrino distribution function of the MC scheme to a two-moment scheme.

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