We study the influence of gravitational microlensing on the AGN Fe Kalpha line confirming that unexpected enhancements recently detected in the iron line of some AGNs can be produced by this effect. We use a ray tracing method to study the influence of microlensing in the emission coming from a compact accretion disc considering both geometries

A numerical method to compute cometary dust tail brightnesses has been developed. The method, analogous in many ways to the inverse Monte Carlo method proposed by Fulle (cite{Fulle89}), has been applied to red continuum images of comet C/1999 T1 McNaught-Hartley obtained by Lara et al. (cite{Lara}). The time and size dependence of the particle

In the present work, we elucidate the meaning of the custodial symmetry and its importance at the phenomenological level in the framework of the standard model of the electroweak interactions and its possible extensions.

We present high-resolution Hα rotation curves for a sample of 15 dwarf and low surface brightness galaxies. From these we derive limits on the slopes of the central mass distributions, using both a direct inversion of the rotation curves and detailed mass models. Assuming that the density distributions of dark matter halos follow a power law at

The color-magnitude diagrams (CMDs) of three intermediate-age Large Megallanic Cloud clusters, NGC 2173, SL 556, and NGC 2155, are analyzed to determine their age and metallicity based on Padova stellar models. Synthetic CMDs are compared with cluster data. The best match is obtained using two fitting functions based on star counts in the different

Using Yale stellar evolution models, we present an analysis of the color-magnitude diagrams (CMDs) of three intermediate-age LMC clusters, namely, NGC 2173, SL 556, and NGC 2155, obtained with the Very Large Telescope. The main goal of our project is to investigate the amount of convective core overshoot necessary to reproduce the CMDs of