The light curve of the outburst of Comet P/Metcalf-Brewington (1991 I) is investigated. The parameters of the light curve are quite uncertain as it may be fitted both in terms of variation with heliocentric distance and exponential decay with time however, after maximum a empirical fit of m1 = 4.1 + 5 log Delta + 14.8 log r gives a good fit to the

Not Available

We propose a new approach to minimize the instrumental polarization (IP) of current polarimetric observations. It is shown how the instrumental polarization can be deduced and removed, by using lines with no intrinsic linear polarization. Notably, no specific understanding of the polarizing properties of our optical setup is required. For the

ESTE TRABAJO ESTA DEDICADO AL ESTUDIO TEORICO DE LA RESPUESTA INDUCIDA POR LA VARIABILIDAD DE LA FUENTE ENERGETICA DE UN NUCLEO ACTIVO EN LA REGION DONDE SE GENERAN LAS LINEAS DE EMISION ANCHAS. CON ESTE OBJETIVO SE HAN CONSIDERADO DOS APROXIMACIONES. EN UNA DE ELLAS SE SUPONE QUE LA RESPUESTA EN LAS LINEAS DE EMISION ES PROPORCIONAL A LA

A sample of HII galaxies has been observed in several radio and optical bands. These galaxies are undergoing very active star formation; they have been selected on the basis of strong radio continuum emission. Radio continuum observations were obtained to determine their radio spectra. Several of the spectra were found to flatten towards lower

Not Available