Now showing items 46-65 of 72

    Near-relativistic electron events. Monte Carlo simulations of solar injection and interplanetary transport 

    Àgueda Costafreda, Neus (Date of defense: 2008-04-28)

    We have developed a Monte Carlo model to simulate the transport of solar near-relativistic (NR; 30-300 keV) electrons along the interplanetary magnetic field (IMF), including adiabatic focusing, pitch-angle dependent ...

    A new classification of gamma-ray bursts and its cosmological implications 

    Balastegui Manso, Andreu (Date of defense: 2006-04-20)

    Los estallidos de rayos gamma (del inglés gamma-ray bursts o GRBs para abreviar) se han clasificado tradicionalmente en GRBs cortos y duros, y GRBs largos y blandos, de acuerdo a la distribución biomodal de sus duraciones. ...

    New Observational Techniques and Analysis Tools for Wide Field CCD Surveys and High Resolution Astrometry 

    Fors Aldrich, Octavi (Date of defense: 2006-03-07)

    The aim of this thesis is two-fold. First it provides a general methodology for applying image deconvolution to wide-field CCD imagery. Second, two new CCD observational techniques and two data analysis tools are proposed ...

    Non-thermal emission from high-energy binaries through interferometric radio observations 

    Marcote Martin, Benito (Date of defense: 2015-10-27)

    High-mass binary systems involve extreme environments that produce non-thermal emission from radio to gamma rays. Only three types of these systems are known to emit persistent gamma-ray emission: colliding-wind binaries, ...

    Observació radiomètrica de radioestrelles 

    Paredes i Poy, Josep Maria (Date of defense: 1987-01-09)

    En aquest treball es presenta l'estudi realitzat, des de l'any 1982, d'un grup d'estrelles que tenen com a característica comuna l'emissió radio. Aquestes estrelles, que anomenarem radioestrelles, i entre les quals no ...

    Observational and theoretical study of the interaction of relativistic winds from young pulsars with inhomogeneous stellar winds 

    Paredes Fortuny, Xavier (Date of defense: 2016-10-17)

    Gamma-ray binaries are systems that comprise a compact object orbiting a companion star and display the maximum of the non-thermal Spectral Energy Distribution (SED) in gamma rays. Currently we know five gamma-ray binaries. ...

    On the characterisation of the Galactic warp in the Gaia era 

    Abedi, Hoda (Date of defense: 2015-02-27)

    We explore the possibility of detecting and characterising the warp of the stellar disc of our Galaxy using synthetic Gaia data and two available proper motion catalogues namely UCAC4 and PPMXL. We develop a new kinematic ...

    Physics of the Intergalactic Medium: a Study of the Power Spectrum ot the Lyman Alpha Forest and the Metal Content of Damped Lyman Alpha Systems 

    Ariño i Prats, Andreu (Date of defense: 2015-02-03)

    El Medi Intergalàctic permet una caracterització de propietats bàsiques de l'univers tals com paràmetres fonamentals del model cosmològic, el creixement de pertorbacions primordials de densitat i formació de galàxies. ...

    Predicció de la radiació solar espectral UV mitjançant models de dispersió múltiple. Aplicació a la predicció de l'índex UV a Catalunya 

    Campmany Pons, Elies (Date of defense: 2005-07-05)

    La predicció de l'índex UV consisteix a determinar la irradiància biològicament efectiva que incidirà en un temps posterior a partir del coneixement dels factors que hi intervenen: l'ozó, l'angle zenital, l'altitud del ...

    Simulació numèrica mesoscalar de l'ozó troposfèric a Catalunya 

    Ortega Jiménez, Sara (Date of defense: 2009-07-14)

    L'ozó és un contaminant secundari que es pot trobar a la troposfera en quantitats elevades en les èpoques amb major radiació solar. Té efectes nocius sobre els éssers vius i per això és necessari controlar les seves ...

    Solar Irradiance Variations Induced by Faculae and Small Magnetic Elements in the Photosphere 

    Ortiz Carbonell, Ada Natalia (Date of defense: 2003-10-10)

    The aim of this thesis is the study of the total and spectral solar irradiance variability induced by the presence of small magnetic elements that emerge into the solar photosphere. It is important to study changes in the ...

    Star formation in cluster environments at Mm and Submm wavelenghts 

    Palau Puigvert, Aina (Date of defense: 2006-07-20)

    [spa] En este trabajo se han observado 4 regiones de formación estelar en modo de cúmulo a longitudes de onda milimétricas y submilimétricas con alta resolución angular (2''-4'') y alta sensibilidad. Para llevar a cabo el ...

    Structure and Dynamics of Clusters and the HI Content of Spiral Galaxies, The 

    Sanchis Estruch, María Teresa (Date of defense: 2003-12-01)

    This thesis is focused on the implication of de dynamics of clusters on the HI content of galaxies. Target of this study has been the Virgo cluster region.<br/><br/>We have first inferred the three-dimensional galaxy ...

    Structure and nature of gamma-ray binaries by means of VLBI observations 

    Moldón Vara, Francisco Javier (Date of defense: 2012-07-05)

    Gamma-ray binaries are extreme systems that produce non-thermal emission from radio to very-high-energy (above TeV) gamma rays, with the energy output in the spectral energy distribution (SED) dominated by the MeV–GeV ...

    Study of Adaptive Optics Images by means of Multiscalar Transforms 

    Baena Gallé, Roberto (Date of defense: 2013-12-09)

    Adaptive optics (AO) systems are used to increase the spatial resolution achieved by ground-based telescopes, which are limited by the atmospheric motion of air layers above them. Therefore, the real cut-off frequency is ...

    Subsynoptic characterization of tropopause fold structure with glogal data anlyses and mesoscale WRF simulations 

    Mateu i Santaeulària, Mireia (Date of defense: 2016-02-05)

    In this work, a subsynoptic characterization of tropopause fold structures is derived from one-year of global, high resolution GFS (Global Forecasting System, 0.3 degrees) data analyses and 10 years of daily WRF (Weather ...

    Superposició de sistemes estel·lars a simetria cilíndrica 

    Cubarsi Morera, Rafael (Date of defense: 1988-11-15)

    S'estudia la superposició de dos sistemes estel·lars a partir de l'aproximació de Chandrasekhar sota la hipòtesi de simetria cilíndrica, en un cas general no estacionari. Les equacions diferencials de Chandrasekhar es ...

    Suspended particulate matter and wet deposition fluxes in regional background stations of the Iberian Peninsula : a detailed study of african dust outbreaks 

    Escudero Tellechea, Miguel (Date of defense: 2006-06-22)

    [spa] La presencia de partículas sólidas y/o líquidas en la atmósfera (aerosol atmosférico) tiene diversas implicaciones sobre el clima, la visibilidad, la salud de los humanos y diversos ciclos biogeoquímicos. Debido a ...

    The effect of activity on the fundamental properties of low-mass stars 

    Morales Peralta, Juan Carlos (Date of defense: 2010-06-14)

    The comparison between stellar structure models and observations of low-mass stars revealed that the stellar radii predicted by models for these stars are about 10% lower than observed, while effective temperatures are ...

    The evolution of the Brewer-Dobson circulation and the ozone layer during the last three decades 

    Ossó Castillón, Albert (Date of defense: 2014-07-10)

    In 1985 Joseph Farman and his colleagues of the British Antarctic Survey published a paper [Farman et al. 1985] showing that the total ozone content of the atmosphere during the Antarctic spring had decreased dramatically ...