The near-infrared (NIR) observations were made on the 3.5m telescope at Calar Alto, Spain (with observation runs of several nights from February 2005 to January 2007). The optical observations were carried out with the Wide Field Imager (WFI) on the MPG/ESO 2.2m telescope at La Silla, Chile during 17-22 March 2007. (2 data files).

Spectro-polarimetry plays an important role in the study of solar magnetism and strongly influences the design of the new generation of solar telescopes. Calibration of the polarization properties of the telescope is a critical requirement needed to use these observations to infer solar magnetic fields. However, the large apertures of these new

We present broadband (gamma-ray, X-ray, near-infrared, optical, and radio) observations of the Swift gamma-ray burst (GRB) 090709A and its afterglow in an effort to ascertain the origin of this high-energy transient. Previous analyses suggested that GRB 090709A exhibited quasi-periodic oscillations with a period of 8.06 s, a trait unknown in long

High resolution spectroscopy demands detector operation in an extremely stable mechanical and thermal environment; any tiny perturbation may affect the location of the detected spectral lines, affecting the instrument global performance. The detector stability has been identified currently as one of the limiting factors to improve radial velocity

We present two conceptual optical designs for a new refractive corrector for the prime focus of the 4.2m William Herschel Telescope, optimised to allow wide-field multi-object spectroscopy. The proposed designs satisfy the demanding requirement that the PSF be smaller than 0.5 arcsec (80% encircled energy) over a two degree FOV and a wavelength

We investigate the role of stellar mass in shaping the intrinsic thickness of galaxy discs by determining the probability distribution of apparent axial ratios (b/a) for two different samples that probe the faint end of the galaxy luminosity function. We find that the b/a distribution has a characteristic `U-shape' and identify a limiting mass M* ~