Finalized Master theses

Número de entradas: 53

Magnetic fields analysis in the LISA PathFinder mission

Estado: defended (03/09/2014)
Estudiante: López Zaragoza, J.P.
Supervisada por: Miquel Nofrarias Serra
Universidad: Universitat Autònoma de Barcelona

The main scientific goal of the LISA Pathfinder (LPF) mission is to put two test masses in an almost perfect free fall, and then measure the differential acceleration existing between them. To achieve this objective, new technologies will be tested, and a full characterization of all the sources…
Estado: defended (03/09/2014)
Estudiante: López Zaragoza, J.P.
Supervisada por: Miquel Nofrarias Serra
Universidad: Universitat Autònoma de Barcelona

The main scientific goal of the LISA Pathfinder (LPF) mission is to put two test masses in an almost perfect free fall, and then measure the differential acceleration existing between them. To achieve this objective, new technologies will be tested, and a full characterization of all the sources of noise that exert some kind of force over the test masses is needed. In this work we will present the characterization done for the magnetic noise. In this work, we characterise a set of real data taken from a month of real simulations performed on the LPF spacecraft, where the conditions that the satellit will face once in space were reproduced. We also show the results obtained for the runs performed using the RJMCMC (model selection) and MCMC (parameter estimation) methods. Using a RJMCMC algorithm we concluded that a model consisting in one source (model #1), the simplest one possible, seems to explain well the data, being closely followed by a model consisting in two sources (model #2). The results from the MCMC method allowed us to provide a first of estimate the magnetic moment of the selected sources with their corresponding error.     

Deep phase modulation for homodyne laser interferometry

Estado: defended (11/07/2014)
Estudiante: Terán, M
Supervisada por: Miquel Nofrarias Serra
Universidad: Universitat Politècnica de Catalunya

Gravitational waves were predicted by Albert Einstein as a direct implication of the theory of General Relativity (1915). Although there are compelling experimental evidences of its existence, its detection has not been possible to the date. LISA (Laser interferometer Space Antenna) mission and its precursor…
Estado: defended (11/07/2014)
Estudiante: Terán, M
Supervisada por: Miquel Nofrarias Serra
Universidad: Universitat Politècnica de Catalunya

Gravitational waves were predicted by Albert Einstein as a direct implication of the theory of General Relativity (1915). Although there are compelling experimental evidences of its existence, its detection has not been possible to the date. LISA (Laser interferometer Space Antenna) mission and its precursor mission LISA Pathfinder were designed as a complementary to terrestrial detectors, like LIGO and VIRGO, in order to obtain direct detection of gravitational waves at the frequency range of 100 μHz < f < 0.1 Hz. In this spectral range, the Universe is rich in gravitational waves sources and the sensitivity of terrestrial detectors is severely degraded. This project describes an implementation of homodyne deep phase modulation interferometer in the context of the space mission LISA, which aims to detect gravitational waves through laser interferometry. In order to do so, a laser diode control has been developed, besides an optical bench where the interferometer is implemented. This interferometric technique is based in a pathlength phase modulation of one interferometer arm with a sinusoidal modulation signal. When the interference is obtained, an algorithm, designed as an extension of the "J1 … J4" method is applied in order to extract the phase value from the interfered signal. This technique has been proposed like an alternative to heterodyne interferometry to be used in some subsystems of the LISA mission due to the ability to achieve similar performances transferring complexity from optics to electronics. The study represents a starting point for future implementation of a test bench with a stable environment to develop a deep phase modulation interferometer operative with picometer sensitivity at the desired frequency range. This sensitivity value is the minimum required by LISA mission to detect gravitational waves in the space.

Strong decay of the Psi(3770) in dense matter

Estado: defended (14/11/2013)
Estudiante: Victor Lopez de Rioja
Supervisada por: Laura Tolos ; Ramos, A.
Universidad: Universitat de Barcelona

The decay of Psi(3770) in D Dbar is analyzed in connection with the future FAIR project at GSI
Estado: defended (14/11/2013)
Estudiante: Victor Lopez de Rioja
Supervisada por: Laura Tolos ; Ramos, A.
Universidad: Universitat de Barcelona

The decay of Psi(3770) in D Dbar is analyzed in connection with the future FAIR project at GSI

Motion around Black Holes in a Pseudo-Newtonian Framework

Estado: defended (18/09/2013)
Estudiante: José Maraver Lerdo de Tejada
Supervisada por: Carlos Sopuerta
Universidad: Universitat Autònoma de Barcelona

La motivación de este trabajo surge de la necesidad de describir sistemas de muchas partículas alrededor de agujeros negros o de sistemas con distribuciones de materia complejos alrededor de agujeros negros. Un  ejemplo de mucha relevancia astrofísica son discos de acreción, los cuales aparecen…
Estado: defended (18/09/2013)
Estudiante: José Maraver Lerdo de Tejada
Supervisada por: Carlos Sopuerta
Universidad: Universitat Autònoma de Barcelona

La motivación de este trabajo surge de la necesidad de describir sistemas de muchas partículas alrededor de agujeros negros o de sistemas con distribuciones de materia complejos alrededor de agujeros negros. Un  ejemplo de mucha relevancia astrofísica son discos de acreción, los cuales aparecen en agujeros negros tanto estelares como supermasivos.  La integración de las ecuaciones del movimiento relativistas es computacionalmente muy intensiva y puede requerir recursos enormes de centros de supercomputacion.  Para aliviar estas necesidades de computación se han utilizado potenciales newtonianos modificados motivados por las ecuaciones relativistas (pseudo-potenciales newtonianos).

Reflectance properties of asteroids and meteorites: Testing Gaia’s spectral capabilities for asteroid taxonomic classification purposes

Estado: defended (15/09/2013)
Estudiante: Jordi Cortés Comellas
Supervisada por: Josep M. Trigo-Rodríguez ; Xavier Luri (UB)
Universidad: Universitat de Barcelona

The intrinsic difficulty of performing remote asteroid characterization has brought scientists to study the reflectance properties of meteorites. Thereby, join studies of meteorite composition and petrology, physical properties and dynamical evolution of asteroids, have been strengthened links between…
Estado: defended (15/09/2013)
Estudiante: Jordi Cortés Comellas
Supervisada por: Josep M. Trigo-Rodríguez ; Xavier Luri (UB)
Universidad: Universitat de Barcelona

The intrinsic difficulty of performing remote asteroid characterization has brought scientists to study the reflectance properties of meteorites. Thereby, join studies of meteorite composition and petrology, physical properties and dynamical evolution of asteroids, have been strengthened links between specific meteorite and asteroid taxonomic classes. Nowadays, the remote characterization of asteroids is made by using reflectance spectroscopy. Reflectance spectroscopy is able to identify a high variety of features associated with minerals that compose the surface of these bodies. In general, except for few undifferentiated bodies that escaped thermal and aqueous alteration processes, most of the rock-forming minerals of asteroids have suffered some degree of thermal and aqueous alteration associated with metamorphism. The most of altered bodies suffered important bulk chemistry changes along the Solar system formation that together with space gardening of divers materials, increased the diversity and complexity of the body surfaces. Aqueous alteration and thermal metamorphism are the mainly processes that promoted mineralogical changes. This work has compiled part of our current knowledge on the reflectance properties of S class asteroids and ordinary chondrites in order to infer GAIA capabilities to detect this asteroid class.

Critical phenomena in gravitational collapse. Study in asymptotically Minkowski and Anti-de Sitter space-times

Estado: defended (12/09/2013)
Estudiante: Daniel Santos Oliván
Supervisada por: Carlos Sopuerta
Universidad: Universitat de Barcelona

We are going to use numerical relativity to focus in the problem of gravitational collapse of a scalar field. The rest chapter of this thesis is dedicated to the classical Choptuik's problem of gravitational collapse in asymptotically flat spacetime. In the second chapter, we try to address a more…
Estado: defended (12/09/2013)
Estudiante: Daniel Santos Oliván
Supervisada por: Carlos Sopuerta
Universidad: Universitat de Barcelona

We are going to use numerical relativity to focus in the problem of gravitational collapse of a scalar field. The rest chapter of this thesis is dedicated to the classical Choptuik's problem of gravitational collapse in asymptotically flat spacetime. In the second chapter, we try to address a more contemporary problem as the gravitational collapse in asymptotically Anti-de Sitter spacetime.

Development of the Detector Tray for the Wide Field Monitor of the Large Observatory For x-ray Timing (LOFT), a medium-class candidate mission in ESA´s Cosmic Vision 2015-2025

Estado: defended (15/07/2013)
Estudiante: Dmitri Karelin
Supervisada por: Margarita Hernanz Carbó
Universidad: Universitat Politècnica de Catalunya

LOFT, the Large Observatory For X-ray Timing, has recently pass the ESA call as one of the four M3 mission candidates that will compete for a launch opportunity at the start of the 2020s. The primary goal of the mission is to study strong-field gravity, black hole masses and spins, and the…
Estado: defended (15/07/2013)
Estudiante: Dmitri Karelin
Supervisada por: Margarita Hernanz Carbó
Universidad: Universitat Politècnica de Catalunya

LOFT, the Large Observatory For X-ray Timing, has recently pass the ESA call as one of the four M3 mission candidates that will compete for a launch opportunity at the start of the 2020s. The primary goal of the mission is to study strong-field gravity, black hole masses and spins, and the equation of state of ultra-dense matter via high-time-resolution Xray observations of compact objects. Two instruments will be comprised in the scientific payload of LOFT: the Large Area Detector (LAD) a 12 m2 collimated X-ray detector in the 2-80 keV range, with unprecedented timing capabilities, and the Wide Field Monitor (WFM), a coded-mask wide field X-ray monitor. Both instruments are based on silicon drift detectors. The main scope of WFM is catch good triggering sources to be pointed with LAD. LOFT’s Wide Field Monitor (WFM) will discover and localize X-ray transients and impulsive events and monitor spectral state changes with unprecedented sensitivity, providing interesting targets for LAD's pointed observations. The working principle of the WFM is the classical sky encoding by coded masks and is widely used in space borne instruments (e.g. INTEGRAL, RXTE/ASM, Swift/BAT). The mask shadow recorded by the position-sensitive detector can be de-convolved by using the proper procedures to recover the image of the sky, with an angular resolution given by the ratio between the mask element size and the mask-detector distance. By using Silicon Drift Detectors (SDDs), with a position resolution

The dynamic behavior and modeling of meteors using the Runge-Kutta algorithm

Estado: defended (11/07/2013)
Estudiante: Joan Dergham
Supervisada por: Josep M. Trigo-Rodríguez
Universidad: Universitat Autònoma de Barcelona

The goal of this master thesis is developing a model to describe the behavior of the meteors during atmospheric deceleration. The process is studied in the framework of the mass drag-loss equations or so-called single body theory which was first described by Brohnsten (1983). The drag-loss equations…
Estado: defended (11/07/2013)
Estudiante: Joan Dergham
Supervisada por: Josep M. Trigo-Rodríguez
Universidad: Universitat Autònoma de Barcelona

The goal of this master thesis is developing a model to describe the behavior of the meteors during atmospheric deceleration. The process is studied in the framework of the mass drag-loss equations or so-called single body theory which was first described by Brohnsten (1983). The drag-loss equations are introduced in a differential form, and depend on parameters like the shape, the density, the initial mass, the ablation coefficient and others. By fitting the curve created by the differential equations to the observational data obtained from multiple-station camera recordings, all these parameters can be obtained. Then, we expect to achieve a better understanding of the meteoroid interaction and the formation of meteors. Basically we will study how the meteoroid decelerates and penetrates into the atmosphere. In particular we will study the entry and ablation model of Chelyabinsk  asteroid.

Cluster Abundance constraints on cosmological parameters using the Fisher matrix formalism

Estado: defended (12/09/2012)
Estudiante: Albert Izard Alberich
Supervisada por: Pablo Fosalba Vela
Universidad: Universitat Autònoma de Barcelona

We present in this master thesis the process of testing and validating a code previously written by the author that implements the Fisher matrix formalism into the abundance of galaxy clusters. During an earlier period of time this code was initially developed, but it missed suitable tests and cross-checks…
Estado: defended (12/09/2012)
Estudiante: Albert Izard Alberich
Supervisada por: Pablo Fosalba Vela
Universidad: Universitat Autònoma de Barcelona

We present in this master thesis the process of testing and validating a code previously written by the author that implements the Fisher matrix formalism into the abundance of galaxy clusters. During an earlier period of time this code was initially developed, but it missed suitable tests and cross-checks to validate it, and this hole is what the present master thesis aims to solve. The environment chosen is Matlab and it is used an already existing code (Fisher4Cast) that implements Fisher matrices in this language.

Implications for compact stars of a nuclear equation-of-state constrained from heavy ion collisions

Estado: defended (02/07/2012)
Estudiante: Eduard Bosch Coch
Supervisada por: Laura Tolos
Universidad: Universitat de Barcelona

Measurements of kaon production at subthreshold energies in heavy-ion collisions point to a soft nuclear equation of state for densities up to two to three times nuclear matter saturation density. We apply these results to study the implications on compact star properties, especially in the context…
Estado: defended (02/07/2012)
Estudiante: Eduard Bosch Coch
Supervisada por: Laura Tolos
Universidad: Universitat de Barcelona

Measurements of kaon production at subthreshold energies in heavy-ion collisions point to a soft nuclear
equation of state for densities up to two to three times nuclear matter saturation density. We apply these results
to study the implications on compact star properties, especially in the context of the recent measurement of
the two solar mass pulsar PSR J1614-2230. The implications are twofold: First, the heavy-ion results constrain
nuclear matter at densities relevant to light neutron stars. Hence, a radius measurement could provide information
about the density dependence of the symmetry energy which is a crucial quantity in nuclear physics. Second,
the information on the nucleon potential obtained from the analysis of the heavy-ion data can be combined with
restrictions from causality on the nuclear equation of state. From this we can derive a limit for the highest allowed
compact star mass of three solar masses.
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An institute of the Consejo Superior de Investigaciones Científicas

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