{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/80608"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/80608","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"General Relativistic Black Hole-Neutron Star Simulations: Effects of Black Hole Spin and Binary Mass Ratio","abstract":"BHNS mergers are candidate engines for generating both short-hard gamma-ray bursts (SGRBs) and detectable gravitational waves. Using our most recent conformal thin-sandwich BHNS initial data (quasicircular binaries representing quasiequilbrium solutions to Einstein's initial value equations) and our fully general relativistic hydrodynamics code, which is now capable of adaptive-mesh refinement (AMR), we are able to efficiently and accurately simulate these binaries for multiple orbits through inspiral, merger, and ringdown. We evolve the metric using the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulation with the standard moving puncture gauge conditions and handle the hydrodynamics with a high-resolution shock-capturing scheme. We explore the effects of BH spin (aligned and anti-aligned with the orbital angular momentum) by evolving three sets of initial data with BH:NS mass ratio q = 3: the data sets are nearly identical, except the BH spin is varied between a/MBH = -0.5 (anti-aligned), 0.0, and 0.75. The number of orbits before merger increases with a/MBH, as expected. We also study the nonspinning BH case in more detail, varying q between 1, 3, and 5. We calculate gravitational waveforms for the cases we simulate and compare them to binary black-hole waveforms. Only a small disk (< 0.01 M&odot; ) forms for the anti-aligned spin case (a/MBH = -0.5) and for the most extreme mass ratio case (q = 5). By contrast, a massive (Mdisk &ap; 0.2 M&odot; ), hot disk forms in the rapidly spinning (a/M BH = 0.75) aligned BH case. Such a disk could drive a SGRB, possibly by, e.g., producing a copious flux of neutrino-antineutrino pairs.","abstract_html":"BHNS mergers are candidate engines for generating both short-hard gamma-ray bursts (SGRBs) and detectable gravitational waves. Using our most recent conformal thin-sandwich BHNS initial data (quasicircular binaries representing quasiequilbrium solutions to Einstein&#x27;s initial value equations) and our fully general relativistic hydrodynamics code, which is now capable of adaptive-mesh refinement (AMR), we are able to efficiently and accurately simulate these binaries for multiple orbits through inspiral, merger, and ringdown. We evolve the metric using the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulation with the standard moving puncture gauge conditions and handle the hydrodynamics with a high-resolution shock-capturing scheme. We explore the effects of BH spin (aligned and anti-aligned with the orbital angular momentum) by evolving three sets of initial data with BH:NS mass ratio q = 3: the data sets are nearly identical, except the BH spin is varied between a/MBH = -0.5 (anti-aligned), 0.0, and 0.75. The number of orbits before merger increases with a/MBH, as expected. We also study the nonspinning BH case in more detail, varying q between 1, 3, and 5. We calculate gravitational waveforms for the cases we simulate and compare them to binary black-hole waveforms. Only a small disk (&lt; 0.01 M&amp;odot; ) forms for the anti-aligned spin case (a/MBH = -0.5) and for the most extreme mass ratio case (q = 5). By contrast, a massive (Mdisk &amp;ap; 0.2 M&amp;odot; ), hot disk forms in the rapidly spinning (a/M BH = 0.75) aligned BH case. Such a disk could drive a SGRB, possibly by, e.g., producing a copious flux of neutrino-antineutrino pairs.","abstract_has_math":false,"creators":["Etienne, Zachariah Burke"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Gammie, Charles F."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-25T20:03:16Z","date_published":"2015-09-25T20:03:16Z","updated_at":"2026-07-22T22:26:14Z","subjects":["Physics, Astronomy and Astrophysics"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI3392007"],"render_values":[{"text":"(MiAaPQ)AAI3392007","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/80608","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Gammie, Charles F."]},{"key":"dc:creator","label":"Author","values":["Etienne, Zachariah Burke"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-25T20:03:16Z","10000-01-01","2009"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"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":["Physics, Astronomy and Astrophysics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/80608","(MiAaPQ)AAI3392007"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["BHNS mergers are candidate engines for generating both short-hard gamma-ray bursts (SGRBs) and detectable gravitational waves. Using our most recent conformal thin-sandwich BHNS initial data (quasicircular binaries representing quasiequilbrium solutions to Einstein's initial value equations) and our fully general relativistic hydrodynamics code, which is now capable of adaptive-mesh refinement (AMR), we are able to efficiently and accurately simulate these binaries for multiple orbits through inspiral, merger, and ringdown. We evolve the metric using the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulation with the standard moving puncture gauge conditions and handle the hydrodynamics with a high-resolution shock-capturing scheme. We explore the effects of BH spin (aligned and anti-aligned with the orbital angular momentum) by evolving three sets of initial data with BH:NS mass ratio q = 3: the data sets are nearly identical, except the BH spin is varied between a/MBH = -0.5 (anti-aligned), 0.0, and 0.75. The number of orbits before merger increases with a/MBH, as expected. We also study the nonspinning BH case in more detail, varying q between 1, 3, and 5. We calculate gravitational waveforms for the cases we simulate and compare them to binary black-hole waveforms. Only a small disk (< 0.01 M&odot; ) forms for the anti-aligned spin case (a/MBH = -0.5) and for the most extreme mass ratio case (q = 5). By contrast, a massive (Mdisk &ap; 0.2 M&odot; ), hot disk forms in the rapidly spinning (a/M BH = 0.75) aligned BH case. Such a disk could drive a SGRB, possibly by, e.g., producing a copious flux of neutrino-antineutrino pairs.","Made available in DSpace on 2015-09-25T20:03:16Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3392007.pdf: 1541939 bytes, checksum: 85bd9479b3b47ff8916051e577afb5a6 (MD5) Previous issue date: 2009","Embargo set by: Seth Robbins for item 81890 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","86 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009."]},{"key":"dc:title","label":"Title","values":["General Relativistic Black Hole-Neutron Star Simulations: Effects of Black Hole Spin and Binary Mass Ratio"]}]}],"canonical_facts":{"dc:contributor":["Gammie, Charles F."],"dc:creator":["Etienne, Zachariah Burke"],"dc:date":["2015-09-25T20:03:16Z","10000-01-01","2009"],"dc:description":["BHNS mergers are candidate engines for generating both short-hard gamma-ray bursts (SGRBs) and detectable gravitational waves. Using our most recent conformal thin-sandwich BHNS initial data (quasicircular binaries representing quasiequilbrium solutions to Einstein's initial value equations) and our fully general relativistic hydrodynamics code, which is now capable of adaptive-mesh refinement (AMR), we are able to efficiently and accurately simulate these binaries for multiple orbits through inspiral, merger, and ringdown. We evolve the metric using the Baumgarte-Shapiro-Shibata-Nakamura (BSSN) formulation with the standard moving puncture gauge conditions and handle the hydrodynamics with a high-resolution shock-capturing scheme. We explore the effects of BH spin (aligned and anti-aligned with the orbital angular momentum) by evolving three sets of initial data with BH:NS mass ratio q = 3: the data sets are nearly identical, except the BH spin is varied between a/MBH = -0.5 (anti-aligned), 0.0, and 0.75. The number of orbits before merger increases with a/MBH, as expected. We also study the nonspinning BH case in more detail, varying q between 1, 3, and 5. We calculate gravitational waveforms for the cases we simulate and compare them to binary black-hole waveforms. Only a small disk (< 0.01 M&odot; ) forms for the anti-aligned spin case (a/MBH = -0.5) and for the most extreme mass ratio case (q = 5). By contrast, a massive (Mdisk &ap; 0.2 M&odot; ), hot disk forms in the rapidly spinning (a/M BH = 0.75) aligned BH case. Such a disk could drive a SGRB, possibly by, e.g., producing a copious flux of neutrino-antineutrino pairs.","Made available in DSpace on 2015-09-25T20:03:16Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 3392007.pdf: 1541939 bytes, checksum: 85bd9479b3b47ff8916051e577afb5a6 (MD5) Previous issue date: 2009","Embargo set by: Seth Robbins for item 81890 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","86 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2009."],"dc:identifier":["http://hdl.handle.net/2142/80608","(MiAaPQ)AAI3392007"],"dc:language":["eng"],"dc:subject":["Physics, Astronomy and Astrophysics"],"dc:title":["General Relativistic Black Hole-Neutron Star Simulations: Effects of Black Hole Spin and Binary Mass Ratio"],"dc:type":["text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:14Z"}