{"id":{"repo_id":"qu-belfast","oai_identifier":"oai:pure.qub.ac.uk/portal:studenttheses/3fc10833-c2d5-4aaa-9483-0dd183dca012"},"canonical_url":"https://search.dev.ndltd.org/etd/qu-belfast/oai:pure.qub.ac.uk/portal:studenttheses/3fc10833-c2d5-4aaa-9483-0dd183dca012","repository":{"repo_id":"qu-belfast","name":"Queen's University Belfast","base_url":"https://pureadmin.qub.ac.uk/ws/oai"},"display":{"title":"Discovering and characterising compact mergers in wide-field surveys","abstract":"This thesis concentrates on efforts to identify and characterize compact mergers involving neutron stars using wide-field survey instruments. With the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) and the Asteroid Terrestrial-impact Last Alert System (ATLAS), searches for compact mergers, including kilonovae, have been performed. The Pan-STARRS search identified two rapidly evolving transients with similar decline rates to the first kilonova, AT2017gfo, in PS15cey and PS17cke. While model fits of black hole-neutron star mergers can match the peak luminosity of PS15cey, a kilonova interpretation is less likely than a rapidly evolving supernova. PS17cke may be a plausible kilonova candidate, however, based on supporting modelling. The ATLAS search has returned no plausible kilonova candidates, but has identified a unique optical transient in AT2018kzr whose peak luminosity and rapid decline are difficult to describe using a traditional Nickel-56 driven explosion models. This necessitates the inclusion of an additional powering source, such as the spin-down of a magnetic neutron star remnant, to provide a plausible model fit to the bolometric lightcurve. Spectral modelling suggests the object is characterised by intermediate mass elements (including oxygen, silicone and magnesium) which disfavours a neutron star-neutron star merger scenario, but is consistent with predictions of white dwarfneutron star mergers. The lack of a kilonova detection by ATLAS has prompted the development of an efficiency simulation to understand the challenges of observing rapidly evolving and intrinsically faint transients with all-sky survey telescopes. Such a simulation has been used to constrain the volumetric rate of AT2017gfo-like transients in the local universe, with the results being consistent with other optically-derived rates estimates and rate of binary neutron star mergers measured gravitational wave observatories. Given the available information, it is predicted ATLAS will need to continue observing for at least a decade in order to observe a kilonova.","abstract_html":"This thesis concentrates on efforts to identify and characterize compact mergers involving neutron stars using wide-field survey instruments. With the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) and the Asteroid Terrestrial-impact Last Alert System (ATLAS), searches for compact mergers, including kilonovae, have been performed. The Pan-STARRS search identified two rapidly evolving transients with similar decline rates to the first kilonova, AT2017gfo, in PS15cey and PS17cke. While model fits of black hole-neutron star mergers can match the peak luminosity of PS15cey, a kilonova interpretation is less likely than a rapidly evolving supernova. PS17cke may be a plausible kilonova candidate, however, based on supporting modelling. The ATLAS search has returned no plausible kilonova candidates, but has identified a unique optical transient in AT2018kzr whose peak luminosity and rapid decline are difficult to describe using a traditional Nickel-56 driven explosion models. This necessitates the inclusion of an additional powering source, such as the spin-down of a magnetic neutron star remnant, to provide a plausible model fit to the bolometric lightcurve. Spectral modelling suggests the object is characterised by intermediate mass elements (including oxygen, silicone and magnesium) which disfavours a neutron star-neutron star merger scenario, but is consistent with predictions of white dwarfneutron star mergers. The lack of a kilonova detection by ATLAS has prompted the development of an efficiency simulation to understand the challenges of observing rapidly evolving and intrinsically faint transients with all-sky survey telescopes. Such a simulation has been used to constrain the volumetric rate of AT2017gfo-like transients in the local universe, with the results being consistent with other optically-derived rates estimates and rate of binary neutron star mergers measured gravitational wave observatories. Given the available information, it is predicted ATLAS will need to continue observing for at least a decade in order to observe a kilonova.","abstract_has_math":false,"creators":["McBrien, Owen"],"institution":"Queen's University Belfast","degree_name":"Doctor of Philosophy","degree_level":"Doctoral Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Smartt, Stephen"],"committee_chairs":[],"committee_members":[],"year":2021,"date_issued":"2021-7","date_published":"2021-7","updated_at":"2026-07-24T03:55:58Z","subjects":["compact mergers","sky surveys","binary neutron star mergers"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["oai:pure.qub.ac.uk/portal:studenttheses/3fc10833-c2d5-4aaa-9483-0dd183dca012"],"render_values":[{"text":"oai:pure.qub.ac.uk/portal:studenttheses/3fc10833-c2d5-4aaa-9483-0dd183dca012","href":null,"code":true}]}]},"links":{"outbound_url":"https://pure.qub.ac.uk/en/studentTheses/3fc10833-c2d5-4aaa-9483-0dd183dca012","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Smartt, Stephen"]},{"key":"dc:creator","label":"Author","values":["McBrien, Owen"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2021-7"]},{"key":"dc:date.issued","label":"Date","values":["2021-7"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["School of Mathematics and Physics"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["Queen's University Belfast"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://pure.qub.ac.uk/en/studentTheses/3fc10833-c2d5-4aaa-9483-0dd183dca012"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral Thesis"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Doctor of Philosophy"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["compact mergers","sky surveys","binary neutron star mergers"]}]},{"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":["oai:pure.qub.ac.uk/portal:studenttheses/3fc10833-c2d5-4aaa-9483-0dd183dca012","https://pure.qub.ac.uk/en/studentTheses/3fc10833-c2d5-4aaa-9483-0dd183dca012"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://pure.qub.ac.uk/files/241869453/Discovering_and_characterising_compact_mergers_in_wide_field_surverys.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This thesis concentrates on efforts to identify and characterize compact mergers involving neutron stars using wide-field survey instruments. With the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) and the Asteroid Terrestrial-impact Last Alert System (ATLAS), searches for compact mergers, including kilonovae, have been performed. The Pan-STARRS search identified two rapidly evolving transients with similar decline rates to the first kilonova, AT2017gfo, in PS15cey and PS17cke. While model fits of black hole-neutron star mergers can match the peak luminosity of PS15cey, a kilonova interpretation is less likely than a rapidly evolving supernova. PS17cke may be a plausible kilonova candidate, however, based on supporting modelling. The ATLAS search has returned no plausible kilonova candidates, but has identified a unique optical transient in AT2018kzr whose peak luminosity and rapid decline are difficult to describe using a traditional Nickel-56 driven explosion models. This necessitates the inclusion of an additional powering source, such as the spin-down of a magnetic neutron star remnant, to provide a plausible model fit to the bolometric lightcurve. Spectral modelling suggests the object is characterised by intermediate mass elements (including oxygen, silicone and magnesium) which disfavours a neutron star-neutron star merger scenario, but is consistent with predictions of white dwarfneutron star mergers. The lack of a kilonova detection by ATLAS has prompted the development of an efficiency simulation to understand the challenges of observing rapidly evolving and intrinsically faint transients with all-sky survey telescopes. Such a simulation has been used to constrain the volumetric rate of AT2017gfo-like transients in the local universe, with the results being consistent with other optically-derived rates estimates and rate of binary neutron star mergers measured gravitational wave observatories. Given the available information, it is predicted ATLAS will need to continue observing for at least a decade in order to observe a kilonova."]},{"key":"dc:title","label":"Title","values":["Discovering and characterising compact mergers in wide-field surveys"]}]}],"canonical_facts":{"dc:contributor.advisor":["Smartt, Stephen"],"dc:creator":["McBrien, Owen"],"dc:date":["2021-7"],"dc:date.issued":["2021-7"],"dc:description.abstract":["This thesis concentrates on efforts to identify and characterize compact mergers involving neutron stars using wide-field survey instruments. With the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) and the Asteroid Terrestrial-impact Last Alert System (ATLAS), searches for compact mergers, including kilonovae, have been performed. The Pan-STARRS search identified two rapidly evolving transients with similar decline rates to the first kilonova, AT2017gfo, in PS15cey and PS17cke. While model fits of black hole-neutron star mergers can match the peak luminosity of PS15cey, a kilonova interpretation is less likely than a rapidly evolving supernova. PS17cke may be a plausible kilonova candidate, however, based on supporting modelling. The ATLAS search has returned no plausible kilonova candidates, but has identified a unique optical transient in AT2018kzr whose peak luminosity and rapid decline are difficult to describe using a traditional Nickel-56 driven explosion models. This necessitates the inclusion of an additional powering source, such as the spin-down of a magnetic neutron star remnant, to provide a plausible model fit to the bolometric lightcurve. Spectral modelling suggests the object is characterised by intermediate mass elements (including oxygen, silicone and magnesium) which disfavours a neutron star-neutron star merger scenario, but is consistent with predictions of white dwarfneutron star mergers. The lack of a kilonova detection by ATLAS has prompted the development of an efficiency simulation to understand the challenges of observing rapidly evolving and intrinsically faint transients with all-sky survey telescopes. Such a simulation has been used to constrain the volumetric rate of AT2017gfo-like transients in the local universe, with the results being consistent with other optically-derived rates estimates and rate of binary neutron star mergers measured gravitational wave observatories. Given the available information, it is predicted ATLAS will need to continue observing for at least a decade in order to observe a kilonova."],"dc:identifier":["oai:pure.qub.ac.uk/portal:studenttheses/3fc10833-c2d5-4aaa-9483-0dd183dca012","https://pure.qub.ac.uk/en/studentTheses/3fc10833-c2d5-4aaa-9483-0dd183dca012"],"dc:identifier.uri":["https://pure.qub.ac.uk/files/241869453/Discovering_and_characterising_compact_mergers_in_wide_field_surverys.pdf"],"dc:language":["eng"],"dc:publisher.department":["School of Mathematics and Physics"],"dc:publisher.institution":["Queen's University Belfast"],"dc:relation.isreferencedby":["https://pure.qub.ac.uk/en/studentTheses/3fc10833-c2d5-4aaa-9483-0dd183dca012"],"dc:subject":["compact mergers","sky surveys","binary neutron star mergers"],"dc:title":["Discovering and characterising compact mergers in wide-field surveys"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["Doctoral Thesis"],"dc:type.qualificationname":["Doctor of Philosophy"]},"updated_at":"2026-07-24T03:55:58Z"}