High Frequency Peaker (HFP) radio sources are an extreme class of active galactic nuclei whose nature has not been fully understood yet. They are compact objects with a simple convex radio spectrum which turns over at frequencies well above a few GHz. In the context of evolutionary models such sources are likely to represent the earliest stage in

We present an analysis of the HD planetary system based on a photometric transit dataset and radial velocities obtained on 3 December 2007. We also present limits on the presence of close stellar companions based on high resolution images.

In this paper we present the first results of a study of BAL QSOs (at low and high redshift), based on very deep Gemini GMOS integral field spectroscopy. In particular, the results obtained for the nearest BAL IR-QSO Mrk 231 are presented. For the nuclear region of Mrk 231, the QSO and host galaxy components were modelled, using a new technique of

Nonionizing stellar continua are a potential source of photons for continuum pumping in the hydrogen Lyman transitions. In the environments where these transitions are optically thick, de-excitation occurs through higher series lines. As a result, the emitted flux in the affected lines has a fluorescent contribution in addition to the usual

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Context: Small-scale magnetic fields play an important role in the structure and the dynamics of the solar atmosphere. Aims: This study aims at revealing the evolution of magnetic fields, together with granular convection in the quiet Sun by means of observations with high spatial, spectral, and temporal resolution and of numerical MHD simulations