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You Must Construct Additional Hypermassive Neutron Stars
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- Author / Creator
- Fahlman, Steven
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We examine the long-term evolution of accretion tori around the remnants of compact object mergers and the explosions of highly magnetized massive stars to better understand their roles in the creation of optical transients and the synthesis of r-process elements. We begin by modifying the FLASH4.5 code to evolve magnetohydrodynamics with simple neutrino transport and a realistic equation of state in 3D spherical coordinates, and provide verification tests. With this new framework, we evolve post-merger systems of tori around black holes and hypermassive neutron stars. We find that magnetic stresses, neutrino driven winds, and thermal effects eject outflows with a broad range of electron fractions, velocities and entropies, sufficient to power kilonovae and produce up to 3rd peak r-process elements. While the ejecta from our simulations cannot match the masses and velocities inferred from two component kilonova modelling of GW170817, more detailed multidimensional kilonova models are needed to see if our outflows are consistent with observations of the blue kilonova. Finally, we detail the modifications to the neutrino scheme and treatment of gravity in FLASH4.5 necessary to run simulations of magnetorotational supernovae, along with further verification tests.
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- Graduation date
- Fall 2023
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- Type of Item
- Thesis
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- Degree
- Doctor of Philosophy
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- License
- This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.