{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/18532"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/18532","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Relativistic Radiative Hydrodynamics Calculation of Accretion Flow into Supermassive Black Hole","abstract":"The compact radio source Sagittarius A* (Sgr A*) is the nearest and most-intensively-studied supermassive black hole candidate. With a broadband spectrum which likely requires several emission mechanisms for explanation, and structure of innermost accretion flow not yet well constrained, the understanding of accretion into Sgr A* demands advances in both theories and computational calculation. To increase the understanding of Sgr A* in particular, and low-luminosity active galactic nuclei in general, we perform relativistic radiative transfer (RT) calculation with general relativistic magnetohydrodynamic (GRMHD) simulation of accretion flow simulation. We are able to use the models to constrain observational parameters of Sgr A*. We also compute the synchrotron emissivity and absorptivity from first principles, in order to verify improved approximate equations for the RT calculation. The code can handle a wide range of electron distributions, therefore the application is not limited to accretion disk simulation. In order to explain a feature in the observed flaring spectrum, we add nonthermal component to the electron distribution. We then perform relativistic Monte Carlo RT calculation of the disk model, and show that a small amount of power-law electron is enough to modify the spectral slope. Finally, we describe a recipe for performing relativistic polarized RT, which would allow a further study to constrain model parameters with polarization observations from Sgr A*.","abstract_html":"The compact radio source Sagittarius A* (Sgr A*) is the nearest and most-intensively-studied supermassive black hole candidate. With a broadband spectrum which likely requires several emission mechanisms for explanation, and structure of innermost accretion flow not yet well constrained, the understanding of accretion into Sgr A* demands advances in both theories and computational calculation. To increase the understanding of Sgr A* in particular, and low-luminosity active galactic nuclei in general, we perform relativistic radiative transfer (RT) calculation with general relativistic magnetohydrodynamic (GRMHD) simulation of accretion flow simulation. We are able to use the models to constrain observational parameters of Sgr A*. We also compute the synchrotron emissivity and absorptivity from first principles, in order to verify improved approximate equations for the RT calculation. The code can handle a wide range of electron distributions, therefore the application is not limited to accretion disk simulation. In order to explain a feature in the observed flaring spectrum, we add nonthermal component to the electron distribution. We then perform relativistic Monte Carlo RT calculation of the disk model, and show that a small amount of power-law electron is enough to modify the spectral slope. Finally, we describe a recipe for performing relativistic polarized RT, which would allow a further study to constrain model parameters with polarization observations from Sgr A*.","abstract_has_math":false,"creators":["Leung, Po Kin"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Astronomy","degree_department":null,"school":null,"contributors":["Gammie, Charles F.","Webbink, Ronald F.","Ricker, Paul M.","Kemball, Athol J."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-01-21T22:44:59Z","date_published":"2011-01-21T22:44:59Z","updated_at":"2026-07-22T22:25:11Z","subjects":["Accretion","Black hole","Supermassive black hole","Synchrotron emission","Sagittarius A*","Radiative transfer"],"languages":["en"],"rights":["2010 by Po Kin Leung. All rights reserved."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/18532","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Gammie, Charles F.","Webbink, Ronald F.","Ricker, Paul M.","Kemball, Athol J."]},{"key":"dc:creator","label":"Author","values":["Leung, Po Kin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-01-21T22:44:59Z","2013-01-22T11:00:22Z","2010-12"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Astronomy"]},{"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":["Accretion","Black hole","Supermassive black hole","Synchrotron emission","Sagittarius A*","Radiative transfer"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["2010 by Po Kin Leung. 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We are able to use the models to constrain observational parameters of Sgr A*. We also compute the synchrotron emissivity and absorptivity from first principles, in order to verify improved approximate equations for the RT calculation. The code can handle a wide range of electron distributions, therefore the application is not limited to accretion disk simulation. In order to explain a feature in the observed flaring spectrum, we add nonthermal component to the electron distribution. We then perform relativistic Monte Carlo RT calculation of the disk model, and show that a small amount of power-law electron is enough to modify the spectral slope. Finally, we describe a recipe for performing relativistic polarized RT, which would allow a further study to constrain model parameters with polarization observations from Sgr A*.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2010-08-27T20:27:01Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Leung_PoKin.pdf: 1367136 bytes, checksum: e0f4c18babe95412d6fb7820f92062cd (MD5)","Made available in DSpace on 2011-01-21T22:44:59Z (GMT). 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In order to explain a feature in the observed flaring spectrum, we add nonthermal component to the electron distribution. We then perform relativistic Monte Carlo RT calculation of the disk model, and show that a small amount of power-law electron is enough to modify the spectral slope. Finally, we describe a recipe for performing relativistic polarized RT, which would allow a further study to constrain model parameters with polarization observations from Sgr A*.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2010-08-27T20:27:01Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Leung_PoKin.pdf: 1367136 bytes, checksum: e0f4c18babe95412d6fb7820f92062cd (MD5)","Made available in DSpace on 2011-01-21T22:44:59Z (GMT). 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All rights reserved."],"dc:subject":["Accretion","Black hole","Supermassive black hole","Synchrotron emission","Sagittarius A*","Radiative transfer"],"dc:title":["Relativistic Radiative Hydrodynamics Calculation of Accretion Flow into Supermassive Black Hole"],"thesis:degree_discipline":["Astronomy"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:11Z"}