Finalized PhD theses

Number of entries: 86

Parallel Post-Processing Solution for GNSS-R Instrument

Status: defended (16/12/2011)
Student: Guo Yi
Supervised by: Antonio Rius Jordán; Ferrer Ramis, Carles
University: Universitat Autònoma de Barcelona

Microelectronica i Sistemes Electrònics
Status: defended (16/12/2011)
Student: Guo Yi
Supervised by: Antonio Rius Jordán; Ferrer Ramis, Carles
University: Universitat Autònoma de Barcelona

Microelectronica i Sistemes Electrònics

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

Status: defended (10/11/2011)
Student: Josep Colomé Ferrer
Supervised by: Ignasi Ribas Canudas
University: 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…
Status: defended (10/11/2011)
Student: Josep Colomé Ferrer
Supervised by: Ignasi Ribas Canudas
University: 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

Status: defended (21/10/2011)
Student: Priscilla Canizares Martinez
Supervised by: Carlos Sopuerta ; José Alberto Lobo Gutiérrez
University: 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…
Status: defended (21/10/2011)
Student: Priscilla Canizares Martinez
Supervised by: Carlos Sopuerta ; José Alberto Lobo Gutiérrez
University: 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

Status: defended (27/07/2011)
Student: Carlo Ferri
Supervised by: Margarita Hernanz Carbó
University: 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…
Status: defended (27/07/2011)
Student: Carlo Ferri
Supervised by: Margarita Hernanz Carbó
University: 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

Status: defended (22/07/2011)
Student: de Cea del Pozo, E.
Supervised by: Diego F. Torres
University: Universitat Autònoma de Barcelona

TBD
Status: defended (22/07/2011)
Student: de Cea del Pozo, E.
Supervised by: Diego F. Torres
University: Universitat Autònoma de Barcelona

TBD

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

Status: defended (31/03/2011)
Student: Diego Sáez-Chillón Gómez
Supervised by: Emilio Elizalde ; Sergei D Odintsov
University: 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…
Status: defended (31/03/2011)
Student: Diego Sáez-Chillón Gómez
Supervised by: Emilio Elizalde ; Sergei D Odintsov
University: 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.

Magnetic fields in star-forming regions: a multi-wavelength approach

Status: defended (03/03/2011)
Student: Felipe Alves
Supervised by: Josep Miquel Girart Medina
University: Universitat de Barcelona

The goal of my thesis is centered in using polarimetry as main tool to study star forming regions. Data obtained in a wide range of wavelengths provide information about the physical processes involved in the formation of star at different scales. In particular, I'm interested in the morphology of the magnetic field and how it varies from molecular clouds (physical scales of a few parsecs) down to protostellar cores (several AU's). I use optical and near-infrared data to derive the field at larger scales, and millimeter/sub-millimeter wavelengths for core scales. It's observed that the field morphology can be significantly distinct in different cases, having a very uniform component for some magnetized clouds (like the Pipe Nebula) or a less ordered field under effects of turbulence. In the mm/submm range, the case of NGC 2024 FIR 5 is being used to test observationally star-forming models. The magnetic field in this core has a partial hourglass geometry, which is proposed by models of ambipolar diffusion or can be disturbed by an ionization front which is expanding close to it. In a general aspect, I'm performing a comparative investigation of the magnetic field morphology for different scales.
The science case of this thesis is focused in the study of the role of the interstellar magnetic field in the star formation process at different physical scales. This study is connected with the gas dynamics at distinct density components. For this purpose, an extensive observational work using distinct…
Status: defended (03/03/2011)
Student: Felipe Alves
Supervised by: Josep Miquel Girart Medina
University: Universitat de Barcelona

The science case of this thesis is focused in the study of the role of the interstellar magnetic field in the star formation process at different physical scales. This study is connected with the gas dynamics at distinct density components. For this purpose, an extensive observational work using distinct astronomical facilities was performed. A multi-scale picture is achieved when distinct magnetic field tracers are used. With this technique, the research described in this thesis aims to study the evolution of astrophysical objects based on their magnetic field morphology. Star-forming theories predict that both quantities are closely related, so the thesis goal is to search for observational evidences for those models. In a more general aspect, this investigation aims to provide an heterogeneous polarization database for molecular clouds at distinct evolutionary stages.

Massive Star Formation: ionized and molecular gas emission in the first evolutionary stages

Status: defended (25/02/2011)
Student: Sánchez-Monge, Álvaro
Supervised by: Dr. Robert Estalella; Dr. Stan Kurtz; Dr. Aina Palau
University: Universitat de Barcelona

First stages of massive star formation not well understood yet. With the goal of studying the relation between the ionized and molecular gas components we have observed with high angular resolution the ionized gas and molecular emission, together with dust continuum emission, of 6 massive star-forming…
Status: defended (25/02/2011)
Student: Sánchez-Monge, Álvaro
Supervised by: Dr. Robert Estalella; Dr. Stan Kurtz; Dr. Aina Palau
University: Universitat de Barcelona

First stages of massive star formation not well understood yet. With the goal of studying the relation between the ionized and molecular gas components we have observed with high angular resolution the ionized gas and molecular emission, together with dust continuum emission, of 6 massive star-forming regions. These data, together with similar data from the literature for 4 additional sources, allow us to search for correlations between the ioniozed and molecular gas components. We find that the sample can be divided into two groups. The most evolved sources, typically showing flat spectral indices in the centimeter range and not well associated with molecular gas, and the youngest sources, showing steep spectral indices in the centimeter range and being well associated with molecular gas, tracing hot core emission, and driving outflows. Some hints of a possible relation between the rotational temperature derived from NH3 and the bolometric luminosity, as well as the collimation factor and the momentum flux and the bolometric luminosity are presented.

Chemical and Dynamical Galaxy Evolution

Status: defended (16/11/2010)
Student: Artigas A.
Supervised by: Isern J.; Bravo E.

Using Smoothed Particle Hydrodynamics simulations (Gadget-2 code) we explore the evolution of an individual galaxy. In the code we have included gas cooling, star formation, gas and metal restitution from dying stars plus supernovae energy and chemical feedback (SNII and SNIa). All the ingredients have been treated statistically thus a high resolution is needed in order to achieve good results. We follow the formation and evolution of a disk-like galaxy, predict the final structure and metallicity evolution.
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Status: defended (16/11/2010)
Student: Artigas A.
Supervised by: Isern J.; Bravo E.

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Evolució quimiodinàmica de la Galàxia

Status: defended (16/11/2010)
Student: Anna Artigas
Supervised by: Jordi Isern Vilaboy
University: Universitat de Barcelona

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Status: defended (16/11/2010)
Student: Anna Artigas
Supervised by: Jordi Isern Vilaboy
University: Universitat de Barcelona

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Institute of Space Sciences (IEEC-CSIC)

Campus UAB, Carrer de Can Magrans, s/n
08193 Barcelona.
Phone: +34 93 737 9788
Email: ice@ice.csic.es
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An institute of the Consejo Superior de Investigaciones Científicas
Affiliated with the Institut d'Estudis Espacials de Catalunya

Affiliated with the Institut d'Estudis Espacials de Catalunya