Context. Gamma-ray bursts are cosmological sources emitting radiation from the gamma-rays to the radio band. Substantial observational efforts have been devoted to the study of gamma-ray bursts during the prompt phase, i.e. the initial burst of high-energy radiation, and during the long-lasting afterglows. In spite of many successes in interpreting

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Traditionally thought as alternatives of each other, it has not been until very recently when Adaptive Optics (AO) and lucky imaging (LI) have been put to work together to achieve angular resolutions in the visible wavelengths comparable to those acquired with an ideal telescope. In this work the mutual benefits of combining fast frame selection (a

At Paranal Observatory in the YEPUN (UT4) telescope, two instruments are installed and equipped with adaptive optics systems: an infrared spectro imager (CONICA) below the adaptive optics module NAOS; and an integral field spectrograph (SINFONI). In the same telescope, the Laser Guide Star Facility (LGSF) is installed to provide a reference star to

Context. The mechanisms giving rise to diffuse radio emission in galaxy clusters, and in particular their connection with cluster mergers, are still debated. Aims: We seek to explore the internal dynamics of the cluster Abell 2294, which has been shown to host a radio halo. Methods: Our analysis is mainly based on redshift data for 88 galaxies

We present measurements of the atmospheric water vapour content above the Roque de los Muchachos Observatory (ORM) obtained using the Global Positioning System (GPS). The GPS measurements have been evaluated by comparison with 940-nm radiometer observations. A statistical analysis of the GPS measurements points to the ORM as an observing site with