The highly convergent iterative methods developed by Trujillo Bueno and Fabiani Bendicho (1995) for radiative transfer (RT) applications are generalized to spherical symmetry with velocity fields. These RT methods are based on Jacobi, Gauss-Seidel (GS), and SOR iteration and they form the basis of a new NLTE multilevel transfer code for atomic and

This paper presents a brief overview of some recent advances in numerical radiative transfer, which may help the molecular astrophysics community to achieve new breakthroughs in the interpretation of spectro-(polarimetric) observations.

We present broadband photometry and provide a quantitative analysis of the structure of galaxies in the inner region of the Abell Cluster 2443 (z~0.1). The galaxy parameters have been derived by fitting a two-component model (Sérsic r1/n bulge and exponential disk) to a magnitude-limited sample. Using a new method of analysis that takes into

We present the photometric history of some luminous blue variable candidate stars of M 33. The search was made with the plates collection of the Bulgarian National Astronomical Observatory. We found that 1, of 6 objects studied, showe d photometric variations consistent with the LBV phase. These new data, together with the LBV type spectrum of the

Oxygen abundances have been derived in a sample of very metal-poor stars from observations of the Oi triplet at /λλ 7771-5 Å and OH lines in the near UV. Iron abundances derived in LTE were corrected for NLTE effects following Thévenin and Idiart [ApJ 521 (1999) 753]. Furthermore, a detailed NLTE analysis of iron lines has been carried out for one

OSIRIS (Optical System for Imaging and low/intermediate-Resolution Integrated Spectroscopy) will be one of the Day One instruments for the Spanish 10.4m telescope GTC at La Palma. One of the scientific projects to be addressed with OSIRIS is the study of the galaxy population in clusters of galaxies at high redshift. Part of the cluster sample