The masses of Neutron Stars
Autor(a) principal: | |
---|---|
Data de Publicação: | 2023 |
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-04102023-161616/ |
Resumo: | After almost 60 years since the discovery of the first pulsar, the physics of Neutron Stars (NSs) still present unanswered questions that could lead to a new era in Science. Being the densest and smallest stars observed in the Universe, with average densities above the nuclear saturation density (rho_sat = 2.8 x 10^ g/cm^3), reproducing their matter in terrestrial laboratories is an extremely difficult challenge. The sample of NSs with measured masses is growing thanks to technological and observational advances. The measurement of macroscopic properties of these objects allows us to trace their origins and understand how they are formed. The observed masses reverted the idea of the existence of a canonical value imprinted at birth. The range of masses, much larger than what was previously considered possible, indicates the existence of different evolutionary paths and histories leading to the formation of NSs. In addition, the observation of extremely massive NSs, such as PSR J0952-0607 (m = 2.35 +- 0.17 M_sun) and many other we will comment through this Thesis, has also raised the problem of the maximum mass predicted by General Relativity (GR) combined with a theory of supranuclear matter. The main objective of this Thesis is to study the mass distribution of NSs applying computational methods of Bayesian analysis to make inferences about its shape and the behavior at the high-mass region. In agreement with previous work, we find that the distribution has a bimodal character, that reflects the existence of at least two different populations of NSs. However, contrary to previous results, we show that these objects can reach masses as high as 2.6 M_sun, supporting, for instance, the classification of the less massive component of the GW190814 event, with a mass m=2.59 +- 0.09 M_sun, as a NS. Given the promising scenario of gravitational wave (GW) detection, that can help solving several problems related to the physics of NSs, part of this Thesis was dedicated to create an online catalog of neutron star binary systems (potential sources of GWs when they coalesce), with the aim of studying how these systems are formed, what distinguish those systems that will coalesce from those that will not, at least on a Hubble time, and which are the \"fingerprints\" from these coalescence that can be translated into observable quantities. Finally, in order to contribute to the problem of the nature of matter found in the interior of these stars, this Thesis also presents an equation of state (EOS) model based on the \"strange matter hypothesis\'\' to describe the internal composition of NSs through a gas of quarks in the state known as color-flavor-locking (CFL). The results obtained support the existence of extremely massive NSs, in agreement with statistical results directly inferred from the observed sample. |
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The masses of Neutron StarsAs massas das Estrelas de NêutronsAnálise bayesianaBayesian analysisEquação de estadoEquation of stateEstrelas de NêutronsMassa máximaMaximum massNeutron starAfter almost 60 years since the discovery of the first pulsar, the physics of Neutron Stars (NSs) still present unanswered questions that could lead to a new era in Science. Being the densest and smallest stars observed in the Universe, with average densities above the nuclear saturation density (rho_sat = 2.8 x 10^ g/cm^3), reproducing their matter in terrestrial laboratories is an extremely difficult challenge. The sample of NSs with measured masses is growing thanks to technological and observational advances. The measurement of macroscopic properties of these objects allows us to trace their origins and understand how they are formed. The observed masses reverted the idea of the existence of a canonical value imprinted at birth. The range of masses, much larger than what was previously considered possible, indicates the existence of different evolutionary paths and histories leading to the formation of NSs. In addition, the observation of extremely massive NSs, such as PSR J0952-0607 (m = 2.35 +- 0.17 M_sun) and many other we will comment through this Thesis, has also raised the problem of the maximum mass predicted by General Relativity (GR) combined with a theory of supranuclear matter. The main objective of this Thesis is to study the mass distribution of NSs applying computational methods of Bayesian analysis to make inferences about its shape and the behavior at the high-mass region. In agreement with previous work, we find that the distribution has a bimodal character, that reflects the existence of at least two different populations of NSs. However, contrary to previous results, we show that these objects can reach masses as high as 2.6 M_sun, supporting, for instance, the classification of the less massive component of the GW190814 event, with a mass m=2.59 +- 0.09 M_sun, as a NS. Given the promising scenario of gravitational wave (GW) detection, that can help solving several problems related to the physics of NSs, part of this Thesis was dedicated to create an online catalog of neutron star binary systems (potential sources of GWs when they coalesce), with the aim of studying how these systems are formed, what distinguish those systems that will coalesce from those that will not, at least on a Hubble time, and which are the \"fingerprints\" from these coalescence that can be translated into observable quantities. Finally, in order to contribute to the problem of the nature of matter found in the interior of these stars, this Thesis also presents an equation of state (EOS) model based on the \"strange matter hypothesis\'\' to describe the internal composition of NSs through a gas of quarks in the state known as color-flavor-locking (CFL). The results obtained support the existence of extremely massive NSs, in agreement with statistical results directly inferred from the observed sample.Após quase 60 anos desde a descoberta do primeiro pulsar, a física das Estrelas de Nêutrons (ENs) ainda apresenta questões não respondidas que podem dar início a uma nova era na Ciência. Sendo as estrelas mais densas e pequenas observadas no Universo, com densidades médias acima da densidade de saturação nuclear (rho_sat = 2.8 × 10^ g/cm^3), a reprodução de sua matéria em laboratórios terrestres se torna extremamente difícil. A amostra de ENs com massas medidas vem crescendo graças aos avanços tecnológicos e observacionais. A medição de propriedades macroscópicas destes objetos permite traçar suas origens e entender como são formados. As massas observadas nos últimos anos colocaram à prova a existência de um valor canônico impresso no nascimento. O intervalo de massas, bem maior do que antes era considerado possível, evidencia a existência de diferentes caminhos evolutivos. Além disso, a observação de ENs extremamente massivas, como o PSR J0952-0607 com m = 2.35 ± 0.17 M_ entre outros que iremos comentar ao longo desta Tese, também tem testado o problema da massa máxima prevista pela Relatividade Geral (RG) combinada com a teoria da matéria supranuclear. Esta Tese tem como objetivo principal aplicar métodos computacionais de análise bayesiana à distribuição de massa das ENs para realizar inferências sobre a sua forma e o comportamento na região de altas massas. Em concordância com trabalhos anteriores, encontramos que a distribuição apresenta um caráter bimodal que se reflete na existência de ao menos duas populações de ENs distintas. No entanto, contrário a resultados prévios, mostramos que estes objetos podem atingir massas tão altas quanto 2.6 M_, dando suporte para classificar a componente menos massiva do evento GW190814, com massa m=2.59^{+0.08}_ M_, como uma EN. Dado o cenário promissor das detecções de ondas gravitacionais (OGs), que pode auxiliar na resolução de diversos problemas relacionados à física das ENs, parte desta Tese foi dedicada à criação de um catálogo online de sistemas duplos de estrelas de nêutrons (eventuais fontes de OGs quando coalescerem), com o intuito de estudar como estes sistemas são formados, o que distingue os sistemas que vão coalescer daqueles que não irão, pelo menos no tempo de Hubble, e quais as \"marcas\" desta coalescência podem ser traduzidas em grandezas observáveis. Por último, visando contribuir para o problema da natureza da matéria encontrada no interior destas estrelas, esta Tese também apresenta um modelo de equação de estado (EE) baseado na \"hipótese da matéria estranha\" para descrever a composição interna de ENs através de um gás de quarks no estado conhecido como color-flavor-locking (CFL). Os resultados obtidos dão suporte à existência de ENs extremamente massivas, em concordância com os resultados estatísticos sobre a amostra inferidos a partir da amostra observada.Biblioteca Digitais de Teses e Dissertações da USPHorvath, Jorge ErnestoRocha, Livia Silva2023-08-07info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfhttps://www.teses.usp.br/teses/disponiveis/14/14131/tde-04102023-161616/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/openAccesseng2023-10-10T11:41:02Zoai:teses.usp.br:tde-04102023-161616Biblioteca 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:27212023-10-10T11:41:02Biblioteca Digital de Teses e Dissertações da USP - Universidade de São Paulo (USP)false |
dc.title.none.fl_str_mv |
The masses of Neutron Stars As massas das Estrelas de Nêutrons |
title |
The masses of Neutron Stars |
spellingShingle |
The masses of Neutron Stars Rocha, Livia Silva Análise bayesiana Bayesian analysis Equação de estado Equation of state Estrelas de Nêutrons Massa máxima Maximum mass Neutron star |
title_short |
The masses of Neutron Stars |
title_full |
The masses of Neutron Stars |
title_fullStr |
The masses of Neutron Stars |
title_full_unstemmed |
The masses of Neutron Stars |
title_sort |
The masses of Neutron Stars |
author |
Rocha, Livia Silva |
author_facet |
Rocha, Livia Silva |
author_role |
author |
dc.contributor.none.fl_str_mv |
Horvath, Jorge Ernesto |
dc.contributor.author.fl_str_mv |
Rocha, Livia Silva |
dc.subject.por.fl_str_mv |
Análise bayesiana Bayesian analysis Equação de estado Equation of state Estrelas de Nêutrons Massa máxima Maximum mass Neutron star |
topic |
Análise bayesiana Bayesian analysis Equação de estado Equation of state Estrelas de Nêutrons Massa máxima Maximum mass Neutron star |
description |
After almost 60 years since the discovery of the first pulsar, the physics of Neutron Stars (NSs) still present unanswered questions that could lead to a new era in Science. Being the densest and smallest stars observed in the Universe, with average densities above the nuclear saturation density (rho_sat = 2.8 x 10^ g/cm^3), reproducing their matter in terrestrial laboratories is an extremely difficult challenge. The sample of NSs with measured masses is growing thanks to technological and observational advances. The measurement of macroscopic properties of these objects allows us to trace their origins and understand how they are formed. The observed masses reverted the idea of the existence of a canonical value imprinted at birth. The range of masses, much larger than what was previously considered possible, indicates the existence of different evolutionary paths and histories leading to the formation of NSs. In addition, the observation of extremely massive NSs, such as PSR J0952-0607 (m = 2.35 +- 0.17 M_sun) and many other we will comment through this Thesis, has also raised the problem of the maximum mass predicted by General Relativity (GR) combined with a theory of supranuclear matter. The main objective of this Thesis is to study the mass distribution of NSs applying computational methods of Bayesian analysis to make inferences about its shape and the behavior at the high-mass region. In agreement with previous work, we find that the distribution has a bimodal character, that reflects the existence of at least two different populations of NSs. However, contrary to previous results, we show that these objects can reach masses as high as 2.6 M_sun, supporting, for instance, the classification of the less massive component of the GW190814 event, with a mass m=2.59 +- 0.09 M_sun, as a NS. Given the promising scenario of gravitational wave (GW) detection, that can help solving several problems related to the physics of NSs, part of this Thesis was dedicated to create an online catalog of neutron star binary systems (potential sources of GWs when they coalesce), with the aim of studying how these systems are formed, what distinguish those systems that will coalesce from those that will not, at least on a Hubble time, and which are the \"fingerprints\" from these coalescence that can be translated into observable quantities. Finally, in order to contribute to the problem of the nature of matter found in the interior of these stars, this Thesis also presents an equation of state (EOS) model based on the \"strange matter hypothesis\'\' to describe the internal composition of NSs through a gas of quarks in the state known as color-flavor-locking (CFL). The results obtained support the existence of extremely massive NSs, in agreement with statistical results directly inferred from the observed sample. |
publishDate |
2023 |
dc.date.none.fl_str_mv |
2023-08-07 |
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-04102023-161616/ |
url |
https://www.teses.usp.br/teses/disponiveis/14/14131/tde-04102023-161616/ |
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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