Studies of Galactic chemical, and dynamical evolution in the solar neighborhood depend on the availability of precise atmospheric parameters (effective temperature T eff, metallicity [Fe/H], and surface gravity log g) for solar-type stars. Many large-scale spectroscopic surveys operate at low to moderate spectral resolution for efficiency in

Reliable extraction of cosmological information from clustering measurements of galaxy surveys requires estimation of the error covariance matrices of observables. The accuracy of covariance matrices is limited by our ability to generate sufficiently large number of independent mock catalogues that can describe the physics of galaxy clustering

We have obtained adaptive optics images and accurate radial velocities for 7 very low mass objects, In the course of a long term effort to determine accurate masses for very low mass stars (M

We present improved visual and near-infrared empirical mass-luminosity relations for very low mass stars (M

We present updated parameters for the star HD 209458 and its transiting giant planet. The stellar angular diameter θ = 0.2254 ± 0.0017 mas is obtained from the average ratio between the absolute flux observed with the Hubble Space Telescope and that of the best-fitting Kurucz model atmosphere. This angular diameter represents an improvement in

First results from the AGN-Heidelberg program aimed at resolving the central pc region of the closest Active Galactic Nuclei in the IR are presented. The core region of prototype active nuclei are clearly unveiled at IR waves and at distances from the nucleus - few pc- where circumnuclear starforming regions appear not to be present. Within that