We present the results of a deep wide-field near-infrared survey of the entire Pleiades cluster recently released as part of the UKIRT Infrared Deep Sky Survey (UKIDSS) Galactic Clusters Survey (GCS) Data Release 9 (DR9). We have identified a sample of ˜1000 Pleiades cluster member candidates combining photometry in five near-infrared passbands and

We present results from the analysis of Fe I 630 nm measurements of the quiet Sun taken with the spectropolarimeter of the Hinode satellite. Two data sets with noise levels of 1.2 × 10-3 and 3 × 10-4 are employed. We determine the distribution of field strengths and inclinations by inverting the two observations with a Milne-Eddington model

Large amplitude longitudinal (LAL) oscillations, consisting of periodic motions of prominence material along a filament axis, are rare but quite dramatic. The oscillations appear to be triggered by an energetic event, such as a microflare, subflare, or small C-class flare, close to a filament. Observations reveal speeds of several tens to 100 km/s

Context. The connection between active galactic nuclei (AGN) and their host galaxies has been widely studied and found to be of great importance for providing answers to some fundamental questions related to AGN fuelling mechanisms, and both their formation and evolution. Aims: Using X-ray data and one of the deepest broad-band optical data sets

The best spectrographs are limited in stability by their calibration light source. Laser frequency combs are the ideal calibrators for astronomical spectrographs. They emit a spectrum of lines that are equally spaced in frequency and that are as accurate and stable as the atomic clock relative to which the comb is stabilized. Absolute calibration

In order to obtain empirical information on the magnetism of the solar transition region we need to measure and interpret the linear polarization produced by scattering processes in FUV and EUV spectral lines. Via the Hanle effect such linear polarization signals are sensitive to the magnetic fields expected for the quiet and active regions of the