We report on the installation of a laser frequency comb (LFC) at the HARPS spectrograph, which we characterize relative to a second LFC that we had brought to HARPS for testing. This allowed us for the first time to probe the relative stability of two independent astronomical LFCs over an extended wavelength range. Both LFCs covered the spectral

Abstract Available from http://www.agu.org

In 2010, we organised a workshop in Tenerife with the aim of bringing together scientists concerned with the completeness and accuracy of atomic data for astrophysical applications. Participants included atomic physicists, theoretical astrophysicists and astronomers, and the workshop covered topics such as the evaluation of uncertainties in atomic

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The conditions of the exosphere of Mercury constitute a prime example of a magnetosphere subject to space weather. We aim at improving the diagnostic of the physical conditions of Na atoms in the exosphere of Mercury, with particular emphasis in the possibility of inferring the magnetic field through polarimetry of the Na D emission lines. We

We present spectra obtained with the 10.4 m Gran Telescopio Canarias telescope of 13 Galactic H II regions, most of them of very low ionization degree. The objects are located along the Galactic disc, with RG from 5.7 to 16.1 kpc. We determine Te([N II]) for all of them. We obtain - for the first time - a radial abundance gradient of N that is