Universitat de Barcelona
Now showing items 50-69 of 72
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 ...
Gamma-ray binaries are systems that comprise a young, massive star and a compact object that can be either a young pulsar or a black hole. They emit radiation from radio up to tens of TeV and show flux variability along ...
The purpose of this work has been the study of Radio Emitting X-Ray Binaries (REXRBs) both from the observational and theoretical approaches. <br/><br/>We have mainly concentrated in the analysis of their properties inferred ...
The region GGD 27, located in Sagittarius at a distance of 1.7 kpc, is an active star forming region. The most well-known observational signature of this region, the HH 80/81/80N jet, is one of the largest collimated jet ...
Java is a very commonly used computer programming language, although its use amongst the scientific and High Performance Computing (HPC) communities remains relatively low. In this thesis, the option of using Java for ...
