We study a complete, colour-selected sample of double-degenerate binary systems containing extremely low mass (ELM) ≤0.25 M&sun; white dwarfs (WDs). We show, for the first time, that Milky Way disc ELM WDs have a merger rate of approximately 4 × 10-5 yr-1 due to gravitational wave radiation. The merger end product depends on the mass ratio of the

According to our present understanding, long gamma-ray bursts (GRBs) originate from the collapse of massive stars, while short bursts are caused by to the coalescence of compact stellar objects. Because the afterglow evolution is determined by the circumburst density profile, n(r), traversed by the fireball, it can be used to distinguish between a

Aims: We re-examine the recombination/collisional emission line (RL/CEL) nebular abundance discrepancy problem in the light of recent high-quality abundance determinations in young stars in the Orion star-forming region. Methods: We re-evaluate the CEL and RL abundances of several elements in the Orion nebula and estimate the associated

The extragalactic background light at far-infrared wavelengths comes from optically faint, dusty, star-forming galaxies in the Universe with star formation rates of a few hundred solar masses per year. These faint, submillimetre galaxies are challenging to study individually because of the relatively poor spatial resolution of far-infrared

We use Very Large Telescope (VLT)/Fibre Large Array Multi Element Spectrograph (FLAMES) intermediate-resolution (R˜ 6500) spectra of individual red giant branch stars in the near-infrared Ca II triplet (CaT) region to investigate the wide-area metallicity properties and internal kinematics of the Sextans dwarf spheroidal galaxy (dSph). Our final

We present physical properties of two submillimeter selected gravitationally lensed sources, identified in the Herschel Astrophysical Terahertz Large Area Survey. These submillimeter galaxies (SMGs) have flux densities >100 mJy at 500 μm, but are not visible in existing optical imaging. We fit light profiles to each component of the lensing systems