Context. The Crab pulsar is the only astronomical pulsed source detected at very high energy (VHE, E > 100 GeV) gamma rays. The emission mechanism of VHE pulsation is not yet fully understood, although several theoretical models have been proposed. Aims: In order to test new models, we measured the light curve and the spectra of the Crab pulsar

We present Galactic mean metallicity maps derived from the first year of the SDSS-III APOGEE experiment. Mean abundances in different zones of projected Galactocentric radius (0 R 15 kpc) at a range of heights above the plane (0 |z| 3 kpc), are derived from a sample of nearly 20,000 giant stars with unprecedented coverage, including stars in

Review of the book : Architecture, Astronomy and Sacred Landscape in Ancient Egypt. Giulio Magli (Cambridge University Press, Cambridge, 2013). Pp. xii + 272. £60. ISBN 978-1-10703-208-8.

Aims: We present a portrait of the active Centaur P/2010 C1 (Scotti), observed with a well developed comet-like activity (central diffuse coma condensation and an extended sharp tail-like structure) at the heliocentric distance of rh = 5.5 AU. Methods: We analyse multicolour (B, V, R, and I) images taken at the TNG telescope to characterise the

This thesis focuses on the quantitative spectroscopic study of the O dwarf population in 30 Doradus (Large Magellanic Cloud, LMC), aiming at clarifying some long-standing open questions about the formation, evolution and physical properties of O stars during their main-sequence phase, where they spend most of their lifetime. This work has been

The fraction of star-forming to quiescent dwarf galaxies varies from almost infinity in the field to zero in the centers of rich galaxy clusters. What is causing this pronounced morphology-density relation? What do quiescent dwarf galaxies look like when studied in detail, and what conclusions can be drawn about their formation mechanism? Here we