We present an analysis of Chandra High Energy Transmission Grating (HETG) spectra of the corona of the critical intermediate-activity, quadruple stellar system ξ UMa. Using the maximum A/B subsystem separation in 2001, we attempted to resolve for the first time in X-rays the two components using the HETG Medium Energy Grating (MEG). We found the Aa

A full understanding of the properties of substellar objects is one of the major challenges facing astrophysics. Since their discovery in 1995, we have discovered hundreds of brown dwarfs and extrasolar planets. While these discoveries have enabled important comparisons with theory, observational progress has been much more rapid than the

ELMER is an instrument for the GTC designed to observe between 365 and 1000 nm. The observing modes for the instrument at Day One shall be: Imaging, Long Slit and Mask-Multi-object Spectroscopy, Slit-less multi-object spectroscopy, Fast Photometry and Fast short-slit spectroscopy, over a FOV of 4.2 arcmin diameter. Spectral resolutions of 250, 1000

SWIRE's wide-area multi-band coverage offers unprecedented opportunities for constructing large, unbiased AGN samples and for studying their cosmological evolution and physical properties. Here we present a collection of SWIRE results, namely on the infrared (IR) luminosity functions and on the tori characteristics of type-1 AGN. Type-1 AGN show

Planetary nebula NGC6543 has a complex structure with a central hot bubble showing both point- and plane symmetry, and a large outer halo that is likely interacting with the local ISM. Between these two structures the HST has revealed a series of a least nine regularly spaced concentric circular rings that are faint and have low contrast. The

Vulcanism was first detected on Io in 1978 by Voyager 1. Since then it has been recognised that Io is the most volcanically active body in the Solar System. Although the initial volcanic activity observed was in the form of SO[2] geysers and sulphur lakes, the Galileo mission has detected temperatures as high as 1800K on the surface, far in excess