Recent focus on the importance of cold, unshocked gas accretion in galaxy formation - not explicitly included in semi-analytic studies - motivates the following detailed comparison between two inherently different modelling techniques: direct hydrodynamical simulation and semi-analytic modelling. By analysing the physical assumptions built into the

The highest resolution images ever taken in the visible were obtained by combining Lucky Imaging and low order adaptive optics. This paper describes a new instrument to be deployed on the WHT 4.2m and GTC 10.4 m telescopes on La Palma, with particular emphasis on the optical design and the expected system performance. A new design of low order

The data and analysis methodology used for the SDSS/APOGEE Data Releases 13 and 14 are described, highlighting differences from the DR12 analysis presented in Holtzman et al. Some improvement in the handling of telluric absorption and persistence is demonstrated. The derivation and calibration of stellar parameters, chemical abundances, and

Data from the SDSS-IV/Apache Point Observatory Galactic Evolution Experiment (APOGEE-2) have been released as part of SDSS Data Releases 13 (DR13) and 14 (DR14). These include high-resolution H-band spectra, radial velocities, and derived stellar parameters and abundances. DR13, released in 2016 August, contained APOGEE data for roughly 150,000

Context. Ground-based imaging and imaging spectropolarimetric data are often subjected to post-facto reconstruction techniques to improve the spatial resolution. Aims: We test the effects of reconstruction techniques on two-dimensional data to determine the best approach to improve our data. Methods: We obtained an 1-h time-series of

In July, the transient neutron star low-mass X-ray binary Aql X-1 was detected in outburst at X-ray, UV, optical and near-infrared wavelengths (ATel #2742, #2744, #2748). On 1st September the X-rays re-brightened (ATel #2850). Here we report on our ongoing optical monitoring campaign (ATel #1218, #1970, #2288) with the Faulkes Telescopes North and