The Mg ii h & k lines are powerful diagnostics for studying the solar chromosphere. They have become particularly popular with the launch of the Interface Region Imaging Spectrograph (IRIS) satellite, and a number of studies that include these lines have lead to great progress in understanding chromospheric heating, in many cases thanks to the

Context. The ever-growing number of large spectroscopic survey programs has increased the importance of fast and reliable methods with which to determine precise stellar parameters. Some of these methods are highly dependent on correct spectroscopic calibrations. Aims: The goal of this work is to obtain a new spectroscopic calibration for a fast

MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is the new optical spectrograph for the 10.4 m Gran Telescopio CANARIAS (GTC). Once installed at GTC by the end of 2016, MEGARA will provide both Integral Field Unit and Multi-Object Spectroscopy capabilities covering a field-of-view of 12.5×11.3 arcsec2 and 3.5×3.5 arcmin2

The cross section for pair production of top quarks (t t ¯ ) with high transverse momenta is measured in p p collisions, collected with the CMS detector at the LHC with √{s }=8 TeV in data corresponding to an integrated luminosity of 19.7 fb-1 . The measurement is performed using lepton +jets events, where one top quark decays semileptonically

Massive stars are key ingredients in the evolution of the Universe. Yet, important uncertainties and limits persist in our understanding of these objects, even in their early phases, limiting their application as tools to interpret the Universe. Here we review some of these open questions and argue that large samples are needed to answer them, both

Aims: We investigate the photometric modulation induced by magnetic activity cycles and study the relationship between rotation period and activity cycle(s) in late-type (FGKM) stars. Methods: We analysed light curves, spanning up to nine years, of 125 nearby stars provided by the All Sky Automated Survey (ASAS). The sample is mainly composed of