A large set of high precision full-Stokes spectro-polarimetric observations of the He I D3 line in spicules has been recorded with the ZIMPOL polarimeter at the Gregory-Coudé Telescope in Locarno. The observational technique allows us to obtain measurements free from seeing-induced spurious effects. The instrumental polarization is well under

We present a theoretical investigation on the influence of the magnetic field on the linear and circular polarization of the Ba II D2 line at 4554 Å, through the Hanle and Zeeman effects. We show in particular the existence of a differential magnetic sensitivity of the three-peak structure of the Q/I profile observed for this line, which is of

We present some theoretical predictions concerning the amplitudes and magnetic sensitivities of the linear polarization signals produced by scattering processes in some UV and FUV spectral lines of the upper chromosphere and transition region, such as Ly-alpha and Mg II k. To this end, we have calculated the atomic level polarization (population

This paper reviews some of the most recent advances in the application of the Hanle effect to solar physics, and how these developments are allowing us to explore the magnetism of the photospheric regions that look ``empty'' in solar magnetograms--that is, the Sun's ``hidden'' magnetism. In particular, we show how a joint analysis of the Hanle

Not Available

We present deep optical images of the historical X-ray Transient KY TrA in quiescence from which we confirm the identification of the counterpart reported by Murdin et al. and derive an improved position of α = 15:28:16.97 and δ = -61:52:57.8. In 2007 June we obtained I, R and V images, where the counterpart seems to be double indicating the