{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/117706"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/117706","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Magnetohydrodynamic simulations of compact stars and binaries in full general relativity","abstract":"Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-04-12 without embargo terms","abstract_html":"Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-04-12 without embargo terms","abstract_has_math":false,"creators":["Sun, Lunan"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Shapiro, Stuart L","Gammie, Charles F","Fields, Brian D","Filippini, Jeffery P"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-12","date_published":"2022-12","updated_at":"2026-07-22T22:24:56Z","subjects":["General Relativity","Numerical Relativity","MHD","Astrophysics","Black Hole","Neutron Stars","Neutrino Transport","Computational Physics"],"languages":["en","eng"],"rights":["Copyright 2022 Lunan Sun"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/117706","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Shapiro, Stuart L","Gammie, Charles F","Fields, Brian D","Filippini, Jeffery P"]},{"key":"dc:creator","label":"Author","values":["Sun, Lunan"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2022-12","2022-08-17"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["General Relativity","Numerical Relativity","MHD","Astrophysics","Black Hole","Neutron Stars","Neutrino Transport","Computational Physics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2022 Lunan Sun"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/117706"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-04-12 without embargo terms","The student, Lunan Sun, accepted the attached license on 2022-08-11 at 10:16.","The student, Lunan Sun, submitted this Dissertation for approval on 2022-08-11 at 10:26.","This Dissertation was approved for publication on 2022-08-17 at 09:22.","DSpace SAF Submission Ingestion Package generated from Vireo submission #18455 on 2023-04-12 at 07:22:59","For years, the original Illinois GRMHD code developed by the Illinois Relativity Group has been used to study numerous interesting and insightful astrophysical systems in strong gravity and magnetic fields. Employing this code, for example, we performed fully general relativistic, magnetohydrodynamic (GRMHD) simulations of marginally stable, radiation-dominated stars with various magnetic field configurations (unmagnetized, interior-only, and pulsar-like), equations of state (EOSs) (Γ ≳ 4/3, n ≲ 3 polytropes), rotation profiles (uniform and differential rotation), and gas-pressure perturbations. The work is motivated by the unknown origin of the accreting supermassive black holes (SMBHs), which are believed to be the engines that power quasars and active galactic nuclei (AGNs). We also constructed the first dynamically stable, extremely compact neutron star (NS) that contains an ergoregion, a region in which there are no timelike static observers, with a compressible, causal EOS. This exotic model may provide an alternative mechanism for powering short γ-ray bursts (sGRBs), as well as provide potential compact binary candidates inside the mass gap (3 − 5M⊙). This thesis will focus on our most recent, GRMHD simulations of merging binary neutron stars that incorporate both neutrino transport and magnetic fields. Our new radiative transport module for neutrinos adopts a general relativistic, truncated-moment (M1) formalism. The binaries consist of two identical, irrotational stars modeled by the SLy nuclear equation of state(EOS). They are initially in quasicircular orbit and threaded with a poloidal dipole magnetic field that extends from the stellar interior into the exterior, as in typical pulsars. We insert neutrino processes shortly after the merger and focus on the role of neutrinos in launching a jet following the collapse of the hypermassive neutron star (HMNS) remnant to a spinning black hole (BH). We treat two microphysical versions: one (a “warm-up”) evolving a single neutrino species and considering only charged-current processes, and the other evolving three species (νe,ν ̄e,νx) and their related processes. We track the evolution until the system reaches a quasiequilibrium state after BH formation. We find that the BH + disk remnant eventually launches an incipient jet. The electromagnetic Poynting luminosity is ~ 10^{53} erg s^{−1}, consistent with that of typical sGRBs. The effect of neutrino cooling shortens the lifetime of the HMNS and lowers the amplitude of the major peak of the gravitational wave (GW) power spectrum somewhat. After BH formation, neutrinos help clear out the matter near the BH poles, resulting in lower baryon-loaded surrounding debris. The neutrino luminosity resides in the range ~ 10^{52−53} erg s^{−1} once quasiequilibrium is achieved. Comparing with the neutrino-free models, we observe that the inclusion of neutrinos yields similar ejecta masses and is inefficient in carrying off additional angular momentum."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Magnetohydrodynamic simulations of compact stars and binaries in full general relativity"]}]}],"canonical_facts":{"dc:contributor":["Shapiro, Stuart L","Gammie, Charles F","Fields, Brian D","Filippini, Jeffery P"],"dc:creator":["Sun, Lunan"],"dc:date":["2022-12","2022-08-17"],"dc:description":["Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-04-12 without embargo terms","The student, Lunan Sun, accepted the attached license on 2022-08-11 at 10:16.","The student, Lunan Sun, submitted this Dissertation for approval on 2022-08-11 at 10:26.","This Dissertation was approved for publication on 2022-08-17 at 09:22.","DSpace SAF Submission Ingestion Package generated from Vireo submission #18455 on 2023-04-12 at 07:22:59","For years, the original Illinois GRMHD code developed by the Illinois Relativity Group has been used to study numerous interesting and insightful astrophysical systems in strong gravity and magnetic fields. Employing this code, for example, we performed fully general relativistic, magnetohydrodynamic (GRMHD) simulations of marginally stable, radiation-dominated stars with various magnetic field configurations (unmagnetized, interior-only, and pulsar-like), equations of state (EOSs) (Γ ≳ 4/3, n ≲ 3 polytropes), rotation profiles (uniform and differential rotation), and gas-pressure perturbations. The work is motivated by the unknown origin of the accreting supermassive black holes (SMBHs), which are believed to be the engines that power quasars and active galactic nuclei (AGNs). We also constructed the first dynamically stable, extremely compact neutron star (NS) that contains an ergoregion, a region in which there are no timelike static observers, with a compressible, causal EOS. This exotic model may provide an alternative mechanism for powering short γ-ray bursts (sGRBs), as well as provide potential compact binary candidates inside the mass gap (3 − 5M⊙). This thesis will focus on our most recent, GRMHD simulations of merging binary neutron stars that incorporate both neutrino transport and magnetic fields. Our new radiative transport module for neutrinos adopts a general relativistic, truncated-moment (M1) formalism. The binaries consist of two identical, irrotational stars modeled by the SLy nuclear equation of state(EOS). They are initially in quasicircular orbit and threaded with a poloidal dipole magnetic field that extends from the stellar interior into the exterior, as in typical pulsars. We insert neutrino processes shortly after the merger and focus on the role of neutrinos in launching a jet following the collapse of the hypermassive neutron star (HMNS) remnant to a spinning black hole (BH). We treat two microphysical versions: one (a “warm-up”) evolving a single neutrino species and considering only charged-current processes, and the other evolving three species (νe,ν ̄e,νx) and their related processes. We track the evolution until the system reaches a quasiequilibrium state after BH formation. We find that the BH + disk remnant eventually launches an incipient jet. The electromagnetic Poynting luminosity is ~ 10^{53} erg s^{−1}, consistent with that of typical sGRBs. The effect of neutrino cooling shortens the lifetime of the HMNS and lowers the amplitude of the major peak of the gravitational wave (GW) power spectrum somewhat. After BH formation, neutrinos help clear out the matter near the BH poles, resulting in lower baryon-loaded surrounding debris. The neutrino luminosity resides in the range ~ 10^{52−53} erg s^{−1} once quasiequilibrium is achieved. Comparing with the neutrino-free models, we observe that the inclusion of neutrinos yields similar ejecta masses and is inefficient in carrying off additional angular momentum."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/117706"],"dc:language":["en","eng"],"dc:rights":["Copyright 2022 Lunan Sun"],"dc:subject":["General Relativity","Numerical Relativity","MHD","Astrophysics","Black Hole","Neutron Stars","Neutrino Transport","Computational Physics"],"dc:title":["Magnetohydrodynamic simulations of compact stars and binaries in full general relativity"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:56Z"}