Finalized PhD theses

Número de entradas: 80

Populating cosmological simulations with galaxy using the HOD model

Estado: defended (01/02/2013)
Estudiante: Jorge Carretero Palacios
Supervisada por: Francisco Javier Castander Serentill; Enrique Gaztañaga
Universidad: Universitat Autònoma de Barcelona

We want to produce galaxy catalogs from N-body dark matter simulations. Those catalogs should be compare to real data and in this way we will learn about the process of galaxy formation.
Populating cosmological simulations with galaxy using the HOD model
Estado: defended (01/02/2013)
Estudiante: Jorge Carretero Palacios
Supervisada por: Francisco Javier Castander Serentill; Enrique Gaztañaga
Universidad: Universitat Autònoma de Barcelona

Populating cosmological simulations with galaxy using the HOD model

The role of magnetic fields in the formation of low and high mass stars

Estado: defended (12/06/2012)
Estudiante: Frau, P.
Supervisada por: Josep Miquel Girart Medina; Beltrán, M. T.
Universidad: Universitat de Barcelona

The complex interplay among self-gravity, thermal support, turbulence, rotation, and magnetic fields, and ultimately the observable features that arise from them, are not well characterized observationally and, therefore, not well understood theoretically. The fact that the starless cores are diffuse and cold objects, makes them very difficult of observing because their emission is very faint. Our goal in this work is to deepen into the understanding of the formation, survival and evolution of low-mass dense cores. We doubly face this objective since we aim: Firstly, to characterize observationally the physical and chemical properties of magnetized starless dense cores in the earliest stages of evolution to derive the initial conditions for star-formation, and to check whether the magnetic field is playing a role in the evolution of the cores and; Secondly, to compare observations of more evolved Class 0 sources with models of collapse of magnetized clouds to find the most likely initial conditions and dominant physical processes. In order to achieve the first goal, we have selected a sample of starless cores of the Pipe Nebula. This nearby dark molecular cloud complex has a very low star formation efficiency, which makes it an ideal target to study the properties and evolution of pristine starless dense cores. For the second goal, we have selected NGC 1333 IRAS 4A. It is probably the best studied low-mass protostellar dense core, not only through molecular and dust emission, but also through high angular resolution polarimetric observations of the dust emission.
The complex interplay among self-gravity, thermal support, turbulence, rotation, and magnetic fields, and ultimately the observable features that arise from them, are not well characterized observationally and, therefore, not well understood theoretically. The fact that the starless cores are diffuse…
Estado: defended (12/06/2012)
Estudiante: Frau, P.
Supervisada por: Josep Miquel Girart Medina; Beltrán, M. T.
Universidad: Universitat de Barcelona

The complex interplay among self-gravity, thermal support, turbulence, rotation, and magnetic fields, and ultimately the observable features that arise from them, are not well characterized observationally and, therefore, not well understood theoretically. The fact that the starless cores are diffuse and cold objects, makes them very difficult of observing because their emission is very faint. Our goal in this work is to deepen into the understanding of the formation, survival and evolution of low-mass dense cores. We doubly face this objective since we aim: Firstly, to characterize observationally the physical and chemical properties of magnetized starless dense cores in the earliest stages of evolution to derive the initial conditions for star-formation, and to check whether the magnetic field is playing a role in the evolution of the cores and; Secondly, to compare observations of more evolved Class 0 sources with models of collapse of magnetized clouds to find the most likely initial conditions and dominant physical processes. In order to achieve the first goal, we have selected a sample of starless cores of the Pipe Nebula. This nearby dark molecular cloud complex has a very low star formation efficiency, which makes it an ideal target to study the properties and evolution of pristine starless dense cores. For the second goal, we have selected NGC 1333 IRAS 4A. It is probably the best studied low-mass protostellar dense core, not only through molecular and dust emission, but also through high angular resolution polarimetric observations of the dust emission.

Star formation ahead of the Herbig-Haro 80N

Estado: defended (23/03/2012)
Estudiante: Masqué, J. M.
Supervisada por: Josep Miquel Girart Medina; Estalella, R.
Universidad: Universitat de Barcelona

This thesis is focused in the detailed study of the star formation process found ahead of the Herbig-Haro 80N
This thesis aims at probing the influence of protostellar outflows to nearby star forming cores by studying the particular case of the HH 80N core. To do so, we first study the chemical properties of the core in the frame of HH photoillumination. The HH 80N core is larger and more massive than other HH…
Estado: defended (23/03/2012)
Estudiante: Masqué, J. M.
Supervisada por: Josep Miquel Girart Medina; Estalella, R.
Universidad: Universitat de Barcelona

This thesis aims at probing the influence of protostellar outflows to nearby star forming cores by studying the particular case of the HH 80N core. To do so, we first study the chemical properties of the core in the frame of HH photoillumination. The HH 80N core is larger and more massive than other HH irradiated clumps, and harbors an embedded object, suggesting a different nature for this core. Our first goal is to see if the HH 80N core has a chemistry similar to that observed in other clumps ahead of HH objects. In the following step, we study the physical properties of the HH 80N core in order to look for evidence of the influence of the HH 80/81/80N jet in the star formation process that is taking place in this core. While many studies on triggered star formation are based on the statistics of a large number of objects \citep[e.g.][]{chauhan2011}, in this thesis we focus our study on an isolated star-forming core to find direct evidence of interaction of the HH 80/81/80N outflow with the core.

Focal plane detectors of a Laue lens telescope for Nuclear Astrophysics

Estado: defended (31/01/2012)
Estudiante: José Manuel Álvarez Pastor
Supervisada por: Margarita Hernanz
Universidad: Universitat Autònoma de Barcelona

TBW
Estado: defended (31/01/2012)
Estudiante: José Manuel Álvarez Pastor
Supervisada por: Margarita Hernanz
Universidad: Universitat Autònoma de Barcelona

TBW

Parallel Post-Processing Solution for GNSS-R Instrument

Estado: defended (16/12/2011)
Estudiante: Guo Yi
Supervisada por: Antonio Rius Jordán; Ferrer Ramis, Carles
Universidad: Universitat Autònoma de Barcelona

Microelectronica i Sistemes Electrònics
Estado: defended (16/12/2011)
Estudiante: Guo Yi
Supervisada por: Antonio Rius Jordán; Ferrer Ramis, Carles
Universidad: Universitat Autònoma de Barcelona

Microelectronica i Sistemes Electrònics

The Joan Oró Telescope at the Montsec Astronomical Observatory Solutions for Unattended Operation

Estado: defended (10/11/2011)
Estudiante: Josep Colomé Ferrer
Supervisada por: Ignasi Ribas Canudas
Universidad: Universitat de Barcelona

El objetivo principal de esta Tesis ha sido la robotización del Telescopio Joan Oró del Observatorio Astronómico del Montsec (TJO-OAdM) para conseguir un sistema con un alto nivel de autonomía y eficiencia. El telescopio robótico TJO-OAdM fue propuesto a mediados de los años 90 y representaba en…
Estado: defended (10/11/2011)
Estudiante: Josep Colomé Ferrer
Supervisada por: Ignasi Ribas Canudas
Universidad: Universitat de Barcelona

El objetivo principal de esta Tesis ha sido la robotización del Telescopio Joan Oró del Observatorio Astronómico del Montsec (TJO-OAdM) para conseguir un sistema con un alto nivel de autonomía y eficiencia. El telescopio robótico TJO-OAdM fue propuesto a mediados de los años 90 y representaba en ese momento un reto tecnológico para el campo de la instrumentación astronómica. Se concibió como un telescopio multipropósito con una operación completamente desatendida. El desarrollo inicial no cumplió con las expectativas de funcionamiento. Tenía varias deficiencias causadas principalmente por un desarrollo basado en una instrumentación comercial que no era adecuada para un control desatendido y fiable. Y, además, presentaba una incompleta definición de la arquitectura del sistema para garantizar el control de toda la instalación y de todos los procesos incluidos en el flujo de datos. El trabajo de la Tesis se ha focalizado en aplicar los cambios necesarios en el diseño inicial para tener un sistema capaz de dar respuestas inteligentes a cualquier situación así como proporcionar un control desatendido del flujo completo de datos. Las especificaciones incluyen desde la preparación e introducción en el sistema de las propuestas de observación hasta el procesado de los datos y la posterior entrega a los usuarios. El aislamiento del lugar y las condiciones meteorológicas extremas añaden un requerimiento de robustez al desarrollo del sistema. Se considera fundamental, pues, lograr una alta fiabilidad, robustez y calidad de los datos recogidos para maximizar la eficiencia y el retorno científico. La Tesis se estructura en tres bloques principales: el análisis y diseño del sistema, en el que se definen las necesidades y la estructura de control; la fase de desarrollo, en la que se presentan el diseño y la implementación de los módulos hardware y software que forman parte de la arquitectura de control; y el control de calidad, donde se ha realizado un análisis de riesgo y se han aplicado metodologías de verificación y validación para garantizar que el sistema final cumplía con los requerimientos iniciales.

Simulations of extreme-mass-ratio inspirals in the LISA frequency band

Estado: defended (21/10/2011)
Estudiante: Priscilla Canizares Martinez
Supervisada por: Carlos Sopuerta ; José Alberto Lobo Gutiérrez
Universidad: Universitat Autònoma de Barcelona

LISA, the Laser Interferometer Space Antenna, is a joint mission between the European Space Agency and the National Aeronautics and Space Administration (USA) scheduled to fly in about 10 years. Its primary scientific goal is to carry out low-frequency gravitational wave astronomy, opening in this way a completely new window to the exploration of the universe that is expected to lead to dramatic discoveries in astrophysics and cosmology, as well as tests of the validity of general relativity. The inspiral, driven by gravitational radiation emission, of compact objects into (super)massive black holes sitting at the galactic centers [known as extreme-mass-ratio inspirals (EMRIs)] is one of the main LISA targets. The main goal of this research is to design and produce simulations of EMRIs and obtain precise theoretical gravitational waveforms of the inspiral. These waveforms are crucial in order to extract the signals produced by EMRIs, which will be buried in instrumental noise and the gravitational wave foreground, and later extract relevant physical information from them. To carry these simulations one needs to use perturbative general relativity and the modern techniques for the estimation of the gravitational backreaction.
Extreme-Mass-Ration Inspirals (EMRIs) are astrophysical systems made up of a Stellar-mass Compact Object (SCO) and a Massive Black Hole (MBH). When the SCO is captured by the MBH, it performs highly eccentric and relativistic orbits, which gradually shrink and circularise due to the emission of gravitational…
Estado: defended (21/10/2011)
Estudiante: Priscilla Canizares Martinez
Supervisada por: Carlos Sopuerta ; José Alberto Lobo Gutiérrez
Universidad: Universitat Autònoma de Barcelona

Extreme-Mass-Ration Inspirals (EMRIs) are astrophysical systems made up of a Stellar-mass Compact Object (SCO) and a Massive Black Hole (MBH). When the SCO is captured by the MBH, it performs highly eccentric and relativistic orbits, which gradually shrink and circularise due to the emission of gravitational waves (GW). In order to obtain all the physical information carried by the GWs, we will need to know how to model these kinds of systems. That in practice means to compute the gravitational self-force that drives the inspiral of the SCO. On the other hand, since the SCO orbit depends upon the MBH geometry, EMRIs are an invaluable tool to test alternative theories of gravity. In this talk, we are going to review the gravitational self-force problem and we will see the main points of the new numerical technique that we propose to compute it. Moreover, we are going to see how LISA may test alternative theories of gravity from EMRI detections, mainly the role that self-force will play in the distinction between General Relativity and an alternative theory of gravity like Chern-Simons.

X-rays emission from accreting white dwarfs in post-outburst novae

Estado: defended (27/07/2011)
Estudiante: Carlo Ferri
Supervisada por: Margarita Hernanz
Universidad: Universitat de Barcelona

To be included shortly
Thanks to launch of XMM-Newton and Chandra, and more recently Swift satellite, the number of post-outburst novae detected in X-rays has increased considerably in the last years. Some puzzling results concerning the SSS phase duration, the reestablishment of accretion process and the temporal behavior…
Estado: defended (27/07/2011)
Estudiante: Carlo Ferri
Supervisada por: Margarita Hernanz
Universidad: Universitat de Barcelona

Thanks to launch of XMM-Newton and Chandra, and more recently Swift satellite, the number of post-outburst novae detected in X-rays has increased considerably in the last years. Some puzzling results concerning the SSS phase duration, the reestablishment of accretion process and the temporal behavior have been discovered, providing new insights into the diversity and the evolution of such systems. The present thesis work has been aimed to perform a comprehensive study both in X-ray and optical bands of post-outburst classical novae, particularly Nova Oph 1998 (V2487 Oph) and Nova Cyg 2006 (V2362 Cyg). High resolution spectra and timing information of XMM-Newton and optical ground-based observations have been analized to estimate the basic parameters of the emitting region from these classical novae. This has made it possible to improve the determination of the thermal plasma component parameters (temperature, density) responsible for the Xray emission, to disentangle if there are additional contributions to this emission (e.g. reflection), and to determine the physical properties of the plasma (accreting flow and/or ejecta). In addition timing analysis provided information about periodicities (orbital and rotational) of the binary systems and, therefore, about the nature of the underlying cataclysmic variable (non-magnetic or magnetic, with synchronous or non-synchronous rotation).

Some theoretical and observational aspects on cosmic-ray diffusion

Estado: defended (22/07/2011)
Estudiante: de Cea del Pozo, E.
Supervisada por: Diego F. Torres
Universidad: Universitat Autònoma de Barcelona

TBD
Estado: defended (22/07/2011)
Estudiante: de Cea del Pozo, E.
Supervisada por: Diego F. Torres
Universidad: Universitat Autònoma de Barcelona

TBD

On Friedmann-Lemaître-Robertson-Walker cosmologies in non-standard gravity

Estado: defended (31/03/2011)
Estudiante: Diego Sáez-Chillón Gómez
Supervisada por: Emilio Elizalde ; Sergei D Odintsov
Universidad: Universitat de Barcelona

The main aim of this work is to show how different approaches could resolve the problem of dark energy and model the entire evolution of Universe history, from inflation to the current epoch. The different answers and intrinsic questions related to each model have been analyzed, as none of them is free…
Estado: defended (31/03/2011)
Estudiante: Diego Sáez-Chillón Gómez
Supervisada por: Emilio Elizalde ; Sergei D Odintsov
Universidad: Universitat de Barcelona

The main aim of this work is to show how different approaches could resolve the problem of dark energy and model the entire evolution of Universe history, from inflation to the current epoch. The different answers and intrinsic questions related to each model have been analyzed, as none of them is free of its proper unresolved questions. The possibility to distinguish between different theories is discussed, where the observations as well as possible predictions have to play a fundamental role.
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An institute of the Consejo Superior de Investigaciones Científicas

An institute of the Consejo Superior de Investigaciones Científicas
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