{"id":{"repo_id":"mit","oai_identifier":"oai:dspace.mit.edu:1721.1/114327"},"canonical_url":"https://search.dev.ndltd.org/etd/mit/oai:dspace.mit.edu:1721.1/114327","repository":{"repo_id":"mit","name":"MIT","base_url":"https://dspace.mit.edu/oai/request"},"display":{"title":"Refinements and improvements to a phenomenological model for the jet opening angles of gamma-ray bursts","abstract":"Long duration gamma-ray bursts (GRBs) are thought to originate from the core collapse of massive, rapidly rotating stars - events called \"hypernovae.\" In this thesis, we improve upon a phenomenological model to determine [theta], the jet opening angle of GRBs. We assume that hypernova progenitors are massive stars in binary systems. We calculate [theta] by equating two expressions for the probability of a given GRB being detected - one based on the geometry of the beaming model and the other based on the observed and expected rates of long duration GRBs. These expressions give [theta] as a function of several key physical parameters. We estimate these parameters, perform a Monte Carlo simulation, and obtain the most probable value of [theta] for both single and double jet GRB models. In contrast to previous work, we allow the minimum mass of star-forming galaxies to vary between 10⁶Mo and 10⁷Mo, and we calculate the galactic number density separately for three subtypes of spiral galaxies. For single jet and double jet models, we find that [theta] = 2.8+³.²-¹.². deg and [theta] = 1.9+².²-⁰.⁸. deg respectively. These results are somewhat lower than the results obtained in the earlier stages of this project [15, 16], but are in agreement with values inferred from the observed properties of GRBs [4]. Our results therefore support the assumption that massive binary stars are the progenitors of hypernovae that produce long-duration GRBs.","abstract_html":"Long duration gamma-ray bursts (GRBs) are thought to originate from the core collapse of massive, rapidly rotating stars - events called "hypernovae." In this thesis, we improve upon a phenomenological model to determine [theta], the jet opening angle of GRBs. We assume that hypernova progenitors are massive stars in binary systems. We calculate [theta] by equating two expressions for the probability of a given GRB being detected - one based on the geometry of the beaming model and the other based on the observed and expected rates of long duration GRBs. These expressions give [theta] as a function of several key physical parameters. We estimate these parameters, perform a Monte Carlo simulation, and obtain the most probable value of [theta] for both single and double jet GRB models. In contrast to previous work, we allow the minimum mass of star-forming galaxies to vary between 10⁶Mo and 10⁷Mo, and we calculate the galactic number density separately for three subtypes of spiral galaxies. For single jet and double jet models, we find that [theta] = 2.8+³.²-¹.². deg and [theta] = 1.9+².²-⁰.⁸. deg respectively. These results are somewhat lower than the results obtained in the earlier stages of this project [15, 16], but are in agreement with values inferred from the observed properties of GRBs [4]. Our results therefore support the assumption that massive binary stars are the progenitors of hypernovae that produce long-duration GRBs.","abstract_has_math":false,"creators":["Tsitkin, Yelena"],"institution":"Massachusetts Institute of Technology","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences.","school":null,"contributors":[],"advisors":["Paul C. Joss."],"committee_chairs":[],"committee_members":[],"year":2006,"date_issued":"2006","date_published":"2006","updated_at":"2026-07-22T22:21:11Z","subjects":["Earth, Atmospheric, and Planetary Sciences."],"languages":["eng"],"rights":["MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission."],"rights_urls":["http://dspace.mit.edu/handle/1721.1/7582"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1721.1/114327","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Paul C. 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They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission."]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://dspace.mit.edu/handle/1721.1/7582"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1721.1/114327"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Thesis: S.B. in Planetary Science and Astronomy, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2006.","Cataloged from PDF version of thesis.","Includes bibliographical references (pages 33-35)."]},{"key":"dc:description.abstract","label":"Abstract","values":["Long duration gamma-ray bursts (GRBs) are thought to originate from the core collapse of massive, rapidly rotating stars - events called \"hypernovae.\" In this thesis, we improve upon a phenomenological model to determine [theta], the jet opening angle of GRBs. We assume that hypernova progenitors are massive stars in binary systems. We calculate [theta] by equating two expressions for the probability of a given GRB being detected - one based on the geometry of the beaming model and the other based on the observed and expected rates of long duration GRBs. These expressions give [theta] as a function of several key physical parameters. We estimate these parameters, perform a Monte Carlo simulation, and obtain the most probable value of [theta] for both single and double jet GRB models. In contrast to previous work, we allow the minimum mass of star-forming galaxies to vary between 10⁶Mo and 10⁷Mo, and we calculate the galactic number density separately for three subtypes of spiral galaxies. For single jet and double jet models, we find that [theta] = 2.8+³.²-¹.². deg and [theta] = 1.9+².²-⁰.⁸. deg respectively. These results are somewhat lower than the results obtained in the earlier stages of this project [15, 16], but are in agreement with values inferred from the observed properties of GRBs [4]. Our results therefore support the assumption that massive binary stars are the progenitors of hypernovae that produce long-duration GRBs."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["S.B. in Planetary Science and Astronomy"]},{"key":"dc:title","label":"Title","values":["Refinements and improvements to a phenomenological model for the jet opening angles of gamma-ray bursts"]}]}],"canonical_facts":{"dc:contributor.advisor":["Paul C. Joss."],"dc:contributor.department":["Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences."],"dc:contributor.other":["Massachusetts Institute of Technology. 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We calculate [theta] by equating two expressions for the probability of a given GRB being detected - one based on the geometry of the beaming model and the other based on the observed and expected rates of long duration GRBs. These expressions give [theta] as a function of several key physical parameters. We estimate these parameters, perform a Monte Carlo simulation, and obtain the most probable value of [theta] for both single and double jet GRB models. In contrast to previous work, we allow the minimum mass of star-forming galaxies to vary between 10⁶Mo and 10⁷Mo, and we calculate the galactic number density separately for three subtypes of spiral galaxies. For single jet and double jet models, we find that [theta] = 2.8+³.²-¹.². deg and [theta] = 1.9+².²-⁰.⁸. deg respectively. These results are somewhat lower than the results obtained in the earlier stages of this project [15, 16], but are in agreement with values inferred from the observed properties of GRBs [4]. Our results therefore support the assumption that massive binary stars are the progenitors of hypernovae that produce long-duration GRBs."],"dc:description.degree":["S.B. in Planetary Science and Astronomy"],"dc:identifier.uri":["http://hdl.handle.net/1721.1/114327"],"dc:language.iso":["eng"],"dc:publisher":["Massachusetts Institute of Technology"],"dc:rights":["MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission."],"dc:rights.uri":["http://dspace.mit.edu/handle/1721.1/7582"],"dc:subject":["Earth, Atmospheric, and Planetary Sciences."],"dc:title":["Refinements and improvements to a phenomenological model for the jet opening angles of gamma-ray bursts"],"dc:type":["Thesis"]},"updated_at":"2026-07-22T22:21:11Z"}