The Dynamical State of Star-forming Regions, from Molecular Clouds to Massive Clumps

[eng] Star formation is a fundamental and still largely unsolved problem of astrophysics and cosmology. Its complexity stems from the complex interaction of turbulence, magnetic fields and gravity, and from the onset of different feedback mechanisms from massive stars, such as stellar winds, ionizin...

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Detalles Bibliográficos
Autor: Lu, Zujia
Tipo de recurso: tesis doctoral
Estado:Versión publicada
Fecha de publicación:2022
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/186923
Acceso en línea:https://hdl.handle.net/2445/186923
http://hdl.handle.net/10803/674614
Access Level:acceso abierto
Palabra clave:Astrofísica
Formació d'estels
Simulació per ordinador
Astrophysics
Star formation
Computer simulation
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network_name_str España
repository_id_str
dc.title.none.fl_str_mv The Dynamical State of Star-forming Regions, from Molecular Clouds to Massive Clumps
title The Dynamical State of Star-forming Regions, from Molecular Clouds to Massive Clumps
spellingShingle The Dynamical State of Star-forming Regions, from Molecular Clouds to Massive Clumps
Lu, Zujia
Astrofísica
Formació d'estels
Simulació per ordinador
Astrophysics
Star formation
Computer simulation
title_short The Dynamical State of Star-forming Regions, from Molecular Clouds to Massive Clumps
title_full The Dynamical State of Star-forming Regions, from Molecular Clouds to Massive Clumps
title_fullStr The Dynamical State of Star-forming Regions, from Molecular Clouds to Massive Clumps
title_full_unstemmed The Dynamical State of Star-forming Regions, from Molecular Clouds to Massive Clumps
title_sort The Dynamical State of Star-forming Regions, from Molecular Clouds to Massive Clumps
dc.creator.none.fl_str_mv Lu, Zujia
author Lu, Zujia
author_facet Lu, Zujia
author_role author
dc.contributor.none.fl_str_mv Padoan, Paolo
Pelkonen, Veli-Matti
Universitat de Barcelona. Departament de Física Quàntica i Astrofísica
dc.subject.none.fl_str_mv Astrofísica
Formació d'estels
Simulació per ordinador
Astrophysics
Star formation
Computer simulation
topic Astrofísica
Formació d'estels
Simulació per ordinador
Astrophysics
Star formation
Computer simulation
description [eng] Star formation is a fundamental and still largely unsolved problem of astrophysics and cosmology. Its complexity stems from the complex interaction of turbulence, magnetic fields and gravity, and from the onset of different feedback mechanisms from massive stars, such as stellar winds, ionizing radiation and supernovae (SNe). This complexity makes it hard to develop purely analytical theories, so future progress in this field relies heavily on numerical simulations. The main goals of this thesis are to improve our understanding of the formation, evolution and dynamical state of star-forming clouds. This is pursued primarily through the analysis of numerical simulations. In Chapter 1, Chapter 2 and Chapter 3, I give the general scientific background and introduce the methods used throughout the thesis. Chapter 4 consists of the paper where we investigate the effect of SN explosions on the dynamics of molecular clouds (MCs). This work is based on the analysis of a simulation of magneto-hydrodynamic (MHD), SN- driven turbulence in a large interstellar medium (ISM) volume (250 pc). The position and timing of SNe is computed self-consistently for the first time by resolving the formation of individual massive stars. The main conclusions are that SNe are able to generate the turbulence observed within MCs, and they may also be the main mechanism for their formation and dispersal. Chapter 5 is the paper where we study the global properties of MC clumps, that are usually considered as possible progenitors of massive stars. This is achieved by comparing synthetic dust continuum observations of our SN- driven simulation with Herschel's observations. We generate a very large catalog of synthetic compact sources that have properties consistent with the observations. The comparison shows that the observed clumps are often projection effects, so their mass is usually overestimated by a large factor. In addition, a large fraction of clumps that are believed to contain a protostar, based on their spectral-energy distribution, are probably starless. Chapter 6 consists of the publications where we compute and analyze synthetic N2H+ line profiles of a sub-sample of our catalog of synthetic compact sources. Thanks to the line data, we study the dynamical state of the compact sources. We show that the observations largely overestimate the virial parameter of the most massive clumps. This generates an observational correlation between the mass and virial parameters of massive clumps that, according to our results, is primarily and observational artifact. In Chapter 7, I summarize the main conclusions of the papers presented in the thesis and briefly discuss future research directions.
publishDate 2022
dc.date.none.fl_str_mv 2022
dc.type.none.fl_str_mv info:eu-repo/semantics/doctoralThesis
info:eu-repo/semantics/publishedVersion
format doctoralThesis
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/186923
http://hdl.handle.net/10803/674614
url https://hdl.handle.net/2445/186923
http://hdl.handle.net/10803/674614
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.rights.none.fl_str_mv cc by (c) Lu, Zujia, 2022
http://creativecommons.org/licenses/by/3.0/es/
info:eu-repo/semantics/openAccess
rights_invalid_str_mv cc by (c) Lu, Zujia, 2022
http://creativecommons.org/licenses/by/3.0/es/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Universitat de Barcelona
publisher.none.fl_str_mv Universitat de Barcelona
dc.source.none.fl_str_mv Tesis Doctorals - Departament - Física Quàntica i Astrofísica
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
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spelling The Dynamical State of Star-forming Regions, from Molecular Clouds to Massive ClumpsLu, ZujiaAstrofísicaFormació d'estelsSimulació per ordinadorAstrophysicsStar formationComputer simulation[eng] Star formation is a fundamental and still largely unsolved problem of astrophysics and cosmology. Its complexity stems from the complex interaction of turbulence, magnetic fields and gravity, and from the onset of different feedback mechanisms from massive stars, such as stellar winds, ionizing radiation and supernovae (SNe). This complexity makes it hard to develop purely analytical theories, so future progress in this field relies heavily on numerical simulations. The main goals of this thesis are to improve our understanding of the formation, evolution and dynamical state of star-forming clouds. This is pursued primarily through the analysis of numerical simulations. In Chapter 1, Chapter 2 and Chapter 3, I give the general scientific background and introduce the methods used throughout the thesis. Chapter 4 consists of the paper where we investigate the effect of SN explosions on the dynamics of molecular clouds (MCs). This work is based on the analysis of a simulation of magneto-hydrodynamic (MHD), SN- driven turbulence in a large interstellar medium (ISM) volume (250 pc). The position and timing of SNe is computed self-consistently for the first time by resolving the formation of individual massive stars. The main conclusions are that SNe are able to generate the turbulence observed within MCs, and they may also be the main mechanism for their formation and dispersal. Chapter 5 is the paper where we study the global properties of MC clumps, that are usually considered as possible progenitors of massive stars. This is achieved by comparing synthetic dust continuum observations of our SN- driven simulation with Herschel's observations. We generate a very large catalog of synthetic compact sources that have properties consistent with the observations. The comparison shows that the observed clumps are often projection effects, so their mass is usually overestimated by a large factor. In addition, a large fraction of clumps that are believed to contain a protostar, based on their spectral-energy distribution, are probably starless. Chapter 6 consists of the publications where we compute and analyze synthetic N2H+ line profiles of a sub-sample of our catalog of synthetic compact sources. Thanks to the line data, we study the dynamical state of the compact sources. We show that the observations largely overestimate the virial parameter of the most massive clumps. This generates an observational correlation between the mass and virial parameters of massive clumps that, according to our results, is primarily and observational artifact. In Chapter 7, I summarize the main conclusions of the papers presented in the thesis and briefly discuss future research directions.[spa] La formación de estrellas es un problema fundamental y aún en gran parte sin resolver de la astrofísica y la cosmología. Su complejidad se deriva en parte de la existencia de diferentes mecanismos de retroalimentación de las estrellas masivas, como las supernovas (SNe). Los principales objetivos de esta tesis son mejorar nuestra comprensión de la formación, evolución y estado dinámico de las nubes de formación estelar. Esto se persigue principalmente a través del análisis de simulaciones numéricas. En el Capítulo 1, Capítulo 2 y Capítulo 3, doy los antecedentes científicos generales e introduzco los métodos utilizados a lo largo de la tesis. El Capítulo 4 consiste en el artículo en el que investigamos el efecto de las explosiones de SN en la dinámica de las nubes moleculares (MC). Este trabajo se basa en el análisis de una simulación de turbulencia magneto- hidrodinámica (MHD) impulsada por SN en un gran volumen de medio interestelar (ISM) de 250 pc. Las principales conclusiones son que las SNe son capaces de generar la turbulencia observada dentro de las MC, y también pueden ser el principal mecanismo para su formación y dispersión. El Capítulo 5 es el artículo en el que estudiamos las propiedades globales de cúmulos masivos, que normalmente se consideran posibles progenitores de estrellas masivas. Esto se logra comparando las observaciones del continuo de polvo sintético de nuestra simulación impulsada por SN con las observaciones de Herschel. Generamos un catálogo muy grande de fuentes compactas sintéticas que tienen propiedades consistentes con las observaciones. La comparación muestra que los cumulos observados son a menudo efectos de proyección, por lo que su masa suele sobreestimarse por un factor importante. El Capítulo 6 consta del artículo en el que calculamos y analizamos los perfiles de línea de N2H+ sintético de una muestra de nuestro catálogo de fuentes compactas sintéticas, para estudiar su estado dinámico. Mostramos que las observaciones sobrestiman en gran medida el parámetro virial de las fuentes más masivas. En el Capítulo 7, resumo las principales conclusiones de los artículos presentados en la tesis y discuto brevemente las direcciones de investigación futuras.Universitat de BarcelonaPadoan, PaoloPelkonen, Veli-MattiUniversitat de Barcelona. Departament de Física Quàntica i Astrofísica2022info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2445/186923http://hdl.handle.net/10803/674614Tesis Doctorals - Departament - Física Quàntica i Astrofísicareponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaIngléscc by (c) Lu, Zujia, 2022http://creativecommons.org/licenses/by/3.0/es/info:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/1869232026-05-27T06:46:51Z
score 15,300724

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