Universitat de Barcelona
Ara mostrant els elements 46-65 de 72
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 ...
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. ...
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 ...
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, ...
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 ...
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. ...
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 ...
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. ...
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 ...
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 ...
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 ...
[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 ...
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 ...
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 ...
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 ...
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 ...
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 ...
[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 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 ...
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 ...
