Echo Tomography is a powerful technique which enables us to probe the accretion geometry in active LMXBs by studying reprocessing of X-rays into UV/optical radiation. If reprocessing takes place in the companion star, time delay as a function of the orbital phase can yield accurate dynamical masses. Previous attempts, using broad band photometry

We present our results of the dynamical analysis of the rich, hot and very X-ray luminous galaxy cluster A2219, containing a powerful diffuse radio-halo.Our conclusions support the view of the connection between extended radio emission and merging phenomena in galaxy clusters.

The chemical composition of the Universe has evolved over billions of years. A host of astrophysical processes and observations must be understood in order to explain why celestial objects have the chemical compositions observed. This book contains the lectures delivered at the XIII Canary Islands Winter School of Astrophysics, which was dedicated

The construction of the GTC (Gran Telescopio Canarias) on La Palma, Canary Islands, is well under way with first light planned for October 2003. All subsystems are developed and are now in the fabrication or commissioning phase. Apart from the suite of instruments, this paper discusses the design and procurement of the CCD camera systems, which are

We discuss the use of the spectral range near 7570 Å to determine the Mg isotopic ratios in carbon stars using the B'2 Sigma +-X 2 Sigma + system of the MgH molecule. We also compare with the spectral range near 5140 Å that has been commonly used in normal stars (oxygen-rich stars). The region near 5140 Å is not the better choice for carbon stars

We discuss abundances of alpha -elements in the ultra-metal-poor giants CS29498-043 and CS22949-037. The abundance of oxygen has been derived from measurements of the oxygen triplet at 7771-5 Å in high resolution and high S/N ratio near-IR spectra obtained with KeckI/HIRES. A detailed non-LTE analysis of Fe lines has been carried to provide more