Research and software
A hot subdwarf in a 7.7 hour orbit with an unseen companion of 1.30 solar masses, close enough to the Chandrasekhar limit that it is unclear whether it is a massive white dwarf or a neutron star.
Orbits for 34 newly found close binaries in the 500 pc sample, giving a short-period binary fraction of 34.7% across 301 hot subdwarfs and a volume-complete estimate of their contribution to the Galactic Type Ia rate.
Atmospheric parameters, masses and Galactic orbits for 253 hot subdwarfs in the 500 pc sample, revealing a population below the extreme horizontal branch that points to intermediate-mass progenitors in the thin disk.
Atmospheric and fundamental parameters for 122 non-composite hot subdwarfs from the Hamburg Quasar Survey. The extremely helium-rich sdOs come out markedly more massive than their hydrogen-rich counterparts, which points at a white dwarf merger origin.
A search across radial velocities, astrometry, common proper motion pairs and light curves finds a binary fraction below 2.2% for blue horizontal-branch stars, against 30 to 50% for their main-sequence and red giant progenitors.
J1903−0023 looked like a hypervelocity star. X-shooter spectroscopy makes it a very metal-poor halo binary instead, tidally synchronised and eclipsing, and a plausible progenitor of a blue lurker.
Multi-Instrument Data Input Reduce-inator. A data reduction toolkit for long slit spectrographs, built so that adding a new instrument is a small job rather than a rewrite.
A complete publication list is onADS.
Slides from talks and lectures are on myuniversity web space.