The focus of the present paper is on the detailed description of the internal structures of low mass, population II stars, to clarify some issues about these stellar models and, mainly, their present reliability for observational comparisons. We then explore 1) the role of the local convective model; 2) the differences between "grey" and "non grey"

The Gran Telescopio Canarias (GTC) is a Spanish initiative, open to international partnership, to construct a 10-m segmented mirror telescope at the Roque de Los Muchachos Observatory, on the Island of La Palma. The GTC first light will be at the end of 2002, while it will be fully operational at the end of 2003. The GTC Global Model (GTCGM), using

The Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) will be a Day-One instrument of the Spanish 10.4 m telescope Gran Telescopio Canarias, whose first light is planned for 2002. GTC will be installed at the Observatorio del Roque de los Muchachos in La Palma, Spain. OSIRIS three primary modes are imaging and low

The Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) is being designed as a Day-One optical instrument for the 10.4 mts Gran Telescopio CANARIAS (GTC). It will be the first instrument, on such a large telescope, belonging to a new class of tunable spectrographs, implementing last advances in Volume Phase Holographic

Here we present the size and luminosity versus velocity dispersion empirical correlations for the giant H II regions in the large irregular galaxy NGC 4449. We show that correlations only hold for nebulae with a surface brightness higher than 2×1035 ergs s-1 pc-2 in Hα and with a supersonic single-line Gaussian profile. The exponents of the fits

We report the case of the early-type disk galaxy NGC 4672 as a new example of a galaxy characterized by the orthogonal geometrical decoupling between bulge and disk. The morphological features of this galaxy are discussed as well as the velocity curves and velocity dispersion profiles of stars and ionized gas along both its major and minor axis. We