Search Publications
SkyMapper stellar parameters for Galactic Archaeology on a grand-scale
Wolf, C.; Yong, D.; Casagrande, L. +3 more
The SkyMapper photometric surveys provides uvgriz photometry for several millions sources in the Southern sky. We use DR1.1 to explore the quality of its photometry, and develop a formalism to homogenize zero-points across the sky using stellar effective temperatures. Physical flux transformations, and zero-points appropriate for this release are …
The wide binary fraction of solar-type stars: emergence of metallicity dependence at a < 200 au
Rix, Hans-Walter; El-Badry, Kareem
We combine a catalogue of wide binaries constructed from Gaia DR2 with [Fe/H] abundances from wide-field spectroscopic surveys to quantify how the binary fraction varies with metallicity over separations 50 ≲ s/au ≲ 50 000. At a given distance, the completeness of the catalogue is independent of metallicity, making it straightforward to constrain …
A hypervelocity star with a Magellanic origin
Boubert, Douglas; Erkal, Denis; Evans, N. Wyn +2 more
Using proper motion measurements from Gaia Data Release 2, we probe the origin of 26 previously known hypervelocity stars (HVSs) around the Milky Way. We find that a significant fraction of these stars have a high probability of originating in the Milky Way Galaxy, but there is one obvious outlier. HVS3 is highly likely to be coming almost from th…
The remarkable X-ray variability of IRAS 13224-3809 - I. The variability process
Young, A. J.; Fabian, A. C.; Reynolds, C. S. +17 more
We present a detailed X-ray timing analysis of the highly variable narrow-line Seyfert 1 (NLS1) galaxy IRAS 13224-3809. The source was recently monitored for 1.5 Ms with XMM-Newton, which, combined with 500 ks archival data, makes this the best-studied NLS1 galaxy in X-rays to date. We apply standard time- and Fourier-domain techniques in order to…
New evidence for the ubiquity of prominent polar dust emission in AGN on tens of parsec scales
Asmus, D.
The key ingredient of active galactic nuclei (AGN) unification, the dusty obscuring torus was so far held responsible for the observed mid-infrared (MIR) emission of AGN. However, the best studied objects with Very Large Telescope Interferometer (VLTI)/MID-infrared Interferometric instrument (MIDI) show that instead a polar dusty wind is dominatin…
Interpretation and diversity of exoplanetary material orbiting white dwarfs
Redfield, Seth; Hollands, Mark; Gänsicke, Boris T. +5 more
Nine metal-polluted white dwarfs are observed with medium-resolution optical spectroscopy, where photospheric abundances are determined and interpreted by comparison with Solar system objects. An improved method for making such comparisons is presented, which overcomes potential weaknesses of prior analyses, with numerous sources of error consider…
The K2-HERMES Survey: age and metallicity of the thick disc
Lewis, Geraint F.; Ting, Yuan-Sen; Huber, Daniel +34 more
Asteroseismology is a promising tool to study Galactic structure and evolution because it can probe the ages of stars. Earlier attempts comparing seismic data from the Kepler satellite with predictions from Galaxy models found that the models predicted more low-mass stars compared to the observed distribution of masses. It was unclear if the misma…
Spatial variations in the Milky Way disc metallicity-age relation
Feuillet, Diane K.; Lind, Karin; García-Hernández, D. A. +5 more
Stellar ages are a crucial component to studying the evolution of the Milky Way. Using Gaia DR2 distance estimates, it is now possible to estimate stellar ages for a larger volume of evolved stars through isochrone matching. This work presents [M/H]-age and [α/M]-age relations derived for different spatial locations in the Milky Way disc. These re…
Feedback from massive stars at low metallicities: MUSE observations of N44 and N180 in the Large Magellanic Cloud
Testi, L.; Evans, C. J.; Kruijssen, J. M. D. +5 more
We present MUSE integral field data of two H II region complexes in the Large Magellanic Cloud: N44 and N180. Both regions consist of a main superbubble and a number of smaller, more compact H II regions that formed on the edge of the superbubble. For a total of 11 H II regions, we systematically analyse the radiative and mechanical feedback from …
A new RASS galaxy cluster catalogue with low contamination extending to z ∼ 1 in the DES overlap region
Smith, M.; D'Andrea, C. B.; Abbott, T. M. C. +63 more
We present the MARD-Y3 catalogue of between 1086 and 2171 galaxy clusters (52 per cent and 65 per cent new) produced using multicomponent matched filter (MCMF) follow-up in 5000 deg2 of DES-Y3 optical data of the ∼20 000 overlapping ROSAT All-Sky Survey source catalogue (2RXS) X-ray sources. Optical counterparts are identified as peaks …