Accretion discs, jets, and black hole spins: a study of blazars
Autor(a) principal: | |
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Data de Publicação: | 2020 |
Tipo de documento: | Tese |
Idioma: | eng |
Título da fonte: | Biblioteca Digital de Teses e Dissertações da USP |
Texto Completo: | https://www.teses.usp.br/teses/disponiveis/14/14131/tde-18052020-103653/ |
Resumo: | Blazars are among the most powerful astrophysical objects in the universe. Their multiwavelength emission displays traces of non-thermal radiation whose origin is not yet fully understood, and it is dominated by the presence of a relativistic jet. Blazar emission is characterized by high-variability across different wavelenghts, which is associated with a spinning black hole and relativistic effects in the jet. Using blazars as a laboratory, in this thesis we set out to answer a few fundamental questions, such as where and how does the non-thermal emission in blazars originate?, how robust are theoretical models in explaining the efficiency of jet formation?, and can these models accurately predict the spins of the black holes associated with these jets? To answer these questions, we employ two different methods: -ray observations and general relativistic magnetohydrodynamic (GRMHD) simulations. In the first study, we used the luminosities of a class of blazars to calculate the jet efficiency, and we estimated the black holes spins. We found a mean spin of a* = 0.84, with a lower limit estimated at a*(lower) = 0.59. These results show compatibility with cosmological merger-driven evolution of SMBHs which support rapidly rotating black holes. Moreover, we found a correlation between the black hole mass and the -ray luminosity L. In the second study, we used GRMHD simulations and applied an algorithm to identify the regions in which non-thermal emission must occur. We ran simulations with different initial conditions, varying the magnetic field topology and black hole spin, and we found these regions in all simulations. In particular, we found that this also occurs in the jet for some simulations, thus suggesting that it is possible to apply radiative transfer to simulation data in order to model non-thermal emission in different astrophysical contexts. |
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Accretion discs, jets, and black hole spins: a study of blazarsDiscos de acreção, jatos, e spins de buracos negros: um estudo de blazaresAccretion discsActive Galactic NucleiBlack holesBlazaresBlazarsBuracos NegrosDiscos de acreçãoNúcleos Ativos de GaláxiasNumerical SimulationsSimulações NuméricasBlazars are among the most powerful astrophysical objects in the universe. Their multiwavelength emission displays traces of non-thermal radiation whose origin is not yet fully understood, and it is dominated by the presence of a relativistic jet. Blazar emission is characterized by high-variability across different wavelenghts, which is associated with a spinning black hole and relativistic effects in the jet. Using blazars as a laboratory, in this thesis we set out to answer a few fundamental questions, such as where and how does the non-thermal emission in blazars originate?, how robust are theoretical models in explaining the efficiency of jet formation?, and can these models accurately predict the spins of the black holes associated with these jets? To answer these questions, we employ two different methods: -ray observations and general relativistic magnetohydrodynamic (GRMHD) simulations. In the first study, we used the luminosities of a class of blazars to calculate the jet efficiency, and we estimated the black holes spins. We found a mean spin of a* = 0.84, with a lower limit estimated at a*(lower) = 0.59. These results show compatibility with cosmological merger-driven evolution of SMBHs which support rapidly rotating black holes. Moreover, we found a correlation between the black hole mass and the -ray luminosity L. In the second study, we used GRMHD simulations and applied an algorithm to identify the regions in which non-thermal emission must occur. We ran simulations with different initial conditions, varying the magnetic field topology and black hole spin, and we found these regions in all simulations. In particular, we found that this also occurs in the jet for some simulations, thus suggesting that it is possible to apply radiative transfer to simulation data in order to model non-thermal emission in different astrophysical contexts.Blazares são alguns dos objetos astrofísicos mais poderosos no universo. Sua emissão ao longo de vários comprimentos de onda apresenta traços de radiação não-térmica cuja origem ainda não é inteiramente compreendida, e ela é dominada pela presença de um jato relativístico. A emissão em blazares é caracterizada por alta variabilidade em vários comprimentos de onda, a qual é associada a um buraco negro em rotação e efeitos relativísticos no jato. Usando blazares como laboratórios, nesta tese nós visamos responder algumas questões fundamentais, tais como onde e como a emissão não-térmica em blazares se origina?, o quão robustos são os modelos teóricos para explicar a eficiência da formação de jatos?, e tais modelos podem prever com precisão os spins dos buracos negros associados a esses jatos? Para responder a essas questões, nós empregamos dois métodos diferentes: observações em raios- e simulações magnetohidrodinâmicas em relatividade geral (GRMHD). No primeiro estudo, utilizamos a luminosidade de uma classe de blazares para calcular a eficiência dos jatos e estimamos os spins dos buracos negros. Nós encontramos um valor médio de a* = 0.84 para o spin, com um limite inferior estimado em a*(lower) = 0.59. Esses resultados mostram compatibilidade com a evolução de buracos negros supermassivos por meio de fusões, originando buracos negros com alta rotação. Além disso, encontramos uma correlação entre a massa dos buracos negros e a luminosidade em raios-, L. No segundo estudo, usamos simulações GRMHD e aplicamos um algoritmo para identificar as regiões em que a emissão não-térmica deve ocorrer. Fizemos simulações com diferentes condições iniciais, variando a topologia do campo magnético e o spin do buraco negro, e encontramos tais regiões em todas as simulações. Em particular, encontramos que isso também ocorre nos jatos para algumas simulações, sugerindo que é possível aplicar transferência radiativa nos dados de simulações para modelar a emissão não-térmica em diferentes contextos astrofísicos.Biblioteca Digitais de Teses e Dissertações da USPSilva, Rodrigo Nemmen daSoares, Gustavo Rodrigues Romano2020-04-06info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfhttps://www.teses.usp.br/teses/disponiveis/14/14131/tde-18052020-103653/reponame:Biblioteca Digital de Teses e Dissertações da USPinstname:Universidade de São Paulo (USP)instacron:USPLiberar o conteúdo para acesso público.info:eu-repo/semantics/openAccesseng2020-05-27T19:56:01Zoai:teses.usp.br:tde-18052020-103653Biblioteca Digital de Teses e Dissertaçõeshttp://www.teses.usp.br/PUBhttp://www.teses.usp.br/cgi-bin/mtd2br.plvirginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.bropendoar:27212020-05-27T19:56:01Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP)false |
dc.title.none.fl_str_mv |
Accretion discs, jets, and black hole spins: a study of blazars Discos de acreção, jatos, e spins de buracos negros: um estudo de blazares |
title |
Accretion discs, jets, and black hole spins: a study of blazars |
spellingShingle |
Accretion discs, jets, and black hole spins: a study of blazars Soares, Gustavo Rodrigues Romano Accretion discs Active Galactic Nuclei Black holes Blazares Blazars Buracos Negros Discos de acreção Núcleos Ativos de Galáxias Numerical Simulations Simulações Numéricas |
title_short |
Accretion discs, jets, and black hole spins: a study of blazars |
title_full |
Accretion discs, jets, and black hole spins: a study of blazars |
title_fullStr |
Accretion discs, jets, and black hole spins: a study of blazars |
title_full_unstemmed |
Accretion discs, jets, and black hole spins: a study of blazars |
title_sort |
Accretion discs, jets, and black hole spins: a study of blazars |
author |
Soares, Gustavo Rodrigues Romano |
author_facet |
Soares, Gustavo Rodrigues Romano |
author_role |
author |
dc.contributor.none.fl_str_mv |
Silva, Rodrigo Nemmen da |
dc.contributor.author.fl_str_mv |
Soares, Gustavo Rodrigues Romano |
dc.subject.por.fl_str_mv |
Accretion discs Active Galactic Nuclei Black holes Blazares Blazars Buracos Negros Discos de acreção Núcleos Ativos de Galáxias Numerical Simulations Simulações Numéricas |
topic |
Accretion discs Active Galactic Nuclei Black holes Blazares Blazars Buracos Negros Discos de acreção Núcleos Ativos de Galáxias Numerical Simulations Simulações Numéricas |
description |
Blazars are among the most powerful astrophysical objects in the universe. Their multiwavelength emission displays traces of non-thermal radiation whose origin is not yet fully understood, and it is dominated by the presence of a relativistic jet. Blazar emission is characterized by high-variability across different wavelenghts, which is associated with a spinning black hole and relativistic effects in the jet. Using blazars as a laboratory, in this thesis we set out to answer a few fundamental questions, such as where and how does the non-thermal emission in blazars originate?, how robust are theoretical models in explaining the efficiency of jet formation?, and can these models accurately predict the spins of the black holes associated with these jets? To answer these questions, we employ two different methods: -ray observations and general relativistic magnetohydrodynamic (GRMHD) simulations. In the first study, we used the luminosities of a class of blazars to calculate the jet efficiency, and we estimated the black holes spins. We found a mean spin of a* = 0.84, with a lower limit estimated at a*(lower) = 0.59. These results show compatibility with cosmological merger-driven evolution of SMBHs which support rapidly rotating black holes. Moreover, we found a correlation between the black hole mass and the -ray luminosity L. In the second study, we used GRMHD simulations and applied an algorithm to identify the regions in which non-thermal emission must occur. We ran simulations with different initial conditions, varying the magnetic field topology and black hole spin, and we found these regions in all simulations. In particular, we found that this also occurs in the jet for some simulations, thus suggesting that it is possible to apply radiative transfer to simulation data in order to model non-thermal emission in different astrophysical contexts. |
publishDate |
2020 |
dc.date.none.fl_str_mv |
2020-04-06 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://www.teses.usp.br/teses/disponiveis/14/14131/tde-18052020-103653/ |
url |
https://www.teses.usp.br/teses/disponiveis/14/14131/tde-18052020-103653/ |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
|
dc.rights.driver.fl_str_mv |
Liberar o conteúdo para acesso público. info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Liberar o conteúdo para acesso público. |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.coverage.none.fl_str_mv |
|
dc.publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
publisher.none.fl_str_mv |
Biblioteca Digitais de Teses e Dissertações da USP |
dc.source.none.fl_str_mv |
reponame:Biblioteca Digital de Teses e Dissertações da USP instname:Universidade de São Paulo (USP) instacron:USP |
instname_str |
Universidade de São Paulo (USP) |
instacron_str |
USP |
institution |
USP |
reponame_str |
Biblioteca Digital de Teses e Dissertações da USP |
collection |
Biblioteca Digital de Teses e Dissertações da USP |
repository.name.fl_str_mv |
Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP) |
repository.mail.fl_str_mv |
virginia@if.usp.br|| atendimento@aguia.usp.br||virginia@if.usp.br |
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1809090830036631552 |