Simultaneous UV and X-ray observations of the blazar PKS 0521-365 are combined with radio, IR, optical and gamma-ray data taken at different epochs to study the overall emission from 109 to 1023 Hz. The energy distribution declines from the IR to the UV range (alpha sub(opt-UV)=1.4 +/- 0.1), but hardens at higher frequencies. The remarkably flat X

Two-dimensional high spatial resoultion Fabry-Perot observations with TAURUS 2 at the William Herschel Telescope in La Palma, over the inner central regions of NGC 604 in M33, have been obtained. The data show a large variety of line profile shapes produced over the region. Some display clear splitting, or strong asymmetries, most likely caused by

EL OBJETO DE ESTA MEMORIA ES EL ESTUDIO DE LA RELACION ENTRE LOS PROCESOS DE FORMACION ESTELAR Y LA ACTIVIDAD EN EL NUCLEO DE LAS GALAXIAS. CON ESTE FIN SE ESTUDIA, EN PRIMER LUGAR, LA FORMACION ESTELAR EN LAS GALAXIAS ANALIZANDO ESTADISTICAMENTE MAS DE 500 REGIONES HII EN 55 GALAXIAS. A PARTIR DE ESTOS DATOS SE DETERMINAN FUNCIONES DE LUMINOSIDAD

We present I-band photometry of the soft X-ray transient (SXT) J0422+32 taken during a low-brightness state over two weeks in 1993 October. The object had a mean V magnitude of 19.9, approximately 2mag above its subsequent, presumably quiescent, level of V~22.4. These data revealed a periodicity at 16.18h (significance level>99 per cent), but we

ESTA TESIS DOCTORAL CONTIENE LOS RESULTADOS DE UN PROGRAMA DE INVESTIGACION EN EL QUE SE HAN DETERMINADO EMPIRICAMENTE LAS RELACIONES TEMPERATURA EFECTIVA-COLOR-METALICIDAD PARA ESTRELLAS DE SECUENCIA PRINCIPAL CON TIPOS ESPECTRALES COMPRENDIDOS EN EL RANGO F0-K5. PARA LLEVAR A CABO ESTA CALIBRACION HA SIDO NECESARIO DESARROLLAR UNA SERIE DE

The amplitude of the gravitational waves emitted by a binary system of arbitrary eccentricity and orientation is developed in Fourier-Bessel series. Periastron advance is also considered. We discuss the influence of the orbital parameters in the spectrum of the wave amplitude. The dominant harmonic in the spectra gives a good estimation of the