Search Publications
Equatorial retrograde flow in WASP-43b elicited by deep wind jets?
Henning, Thomas; Mollière, Paul; Carone, Ludmila +6 more
We present WASP-43b climate simulations with deep wind jets (down to 700 bar) that are linked to retrograde (westward) flow at the equatorial day side for p < 0.1 bar. Retrograde flow inhibits efficient eastward heat transport and naturally explains the small hotspot shift and large day-night-side gradient of WASP-43b (Porb = Pr…
The Pristine Inner Galaxy Survey (PIGS) I: tracing the kinematics of metal-poor stars in the Galactic bulge
Schultheis, M.; Lardo, C.; Sestito, F. +20 more
Our Galaxy is known to contain a central boxy/peanut-shaped bulge, yet the importance of a classical, pressure-supported component within the central part of the Milky Way is still being debated. It should be most visible at low metallicity, a regime that has not yet been studied in detail. Using metallicity-sensitive narrow-band photometry, the P…
Identical or fraternal twins? The chemical homogeneity of wide binaries from Gaia DR2
Ting, Yuan-Sen; Hawkins, Keith; Lucey, Madeline +7 more
One of the high-level goals of Galactic archaeology is chemical tagging of stars across the Milky Way to piece together its assembly history. For this to work, stars born together must be uniquely chemically homogeneous. Wide binary systems are an important laboratory to test this underlying assumption. Here, we present the detailed chemical abund…
Not all stars form in clusters - Gaia-DR2 uncovers the origin of OB associations
Kruijssen, J. M. Diederik; Rix, Hans-Walter; Ward, Jacob L.
Historically, it has often been asserted that most stars form in compact clusters. In this scenario, present-day gravitationally unbound OB associations are the result of the expansion of initially gravitationally bound star clusters. However, this paradigm is inconsistent with recent results, both theoretical and observational, that instead favou…
Reflex motion in the Milky Way stellar halo resulting from the Large Magellanic Cloud infall
Peñarrubia, Jorge; Petersen, Michael S.
We present the results of N-body models of the Milky Way and Large Magellanic Cloud system and study the kinematic reflex motion in the stellar halo owing to the barycentre displacement of the disc. In agreement with previous studies, we find that the Milky Way disc may be moving at 40 km~s^{-1} relative to the barycentre prior to the Large Magell…
Globular clusters in Coma cluster ultra-diffuse galaxies (UDGs): evidence for two types of UDG?
Forbes, Duncan A.; Romanowsky, Aaron J.; Brodie, Jean P. +2 more
Ultra-diffuse galaxies (UDGs) reveal extreme properties. Here, we compile the largest study to date of 85 globular cluster (GC) systems around UDGs in the Coma cluster, using new deep ground-based imaging of the known UDGs and existing imaging from the Hubble Space Telescope of their GC systems. We find that the richness of GC systems in UDGs gene…
2.5D retrieval of atmospheric properties from exoplanet phase curves: application to WASP-43b observations
Irwin, Patrick G. J.; Aigrain, Suzanne; Parmentier, Vivien +4 more
We present a novel retrieval technique that attempts to model phase curve observations of exoplanets more realistically and reliably, which we call the 2.5-dimensional (2.5D) approach. In our 2.5D approach we retrieve the vertical temperature profile and mean gaseous abundance of a planet at all longitudes and latitudes simultaneously, assuming th…
Galaxy And Mass Assembly (GAMA): assimilation of KiDS into the GAMA database
Driver, Simon P.; Robotham, Aaron S. G.; Bellstedt, Sabine +9 more
The Galaxy And Mass Assembly Survey (GAMA) covers five fields with highly complete spectroscopic coverage (>95 per cent) to intermediate depths (r < 19.8 or i < 19.0 mag), and collectively spans 250 deg2 of equatorial or southern sky. Four of the GAMA fields (G09, G12, G15, and G23) reside in the European Southern Observatory (…
Fluctuations in galactic bar parameters due to bar-spiral interaction
Steinmetz, M.; Monari, G.; Famaey, B. +10 more
We study the late-time evolution of the central regions of two Milky Way (MW)-like simulations of galaxies formed in a cosmological context, one hosting a fast bar and the other a slow one. We find that bar length, Rb, measurements fluctuate on a dynamical time-scale by up to 100 per cent, depending on the spiral structure strength and …
Gaia white dwarfs within 40 pc - I. Spectroscopic observations of new candidates
Kepler, S. O.; Hermes, J. J.; Gänsicke, B. T. +30 more
We present a spectroscopic survey of 230 white dwarf candidates within 40 pc of the Sun from the William Herschel Telescope and Gran Telescopio Canarias. All candidates were selected from Gaia Data Release 2 (DR2) and in almost all cases, had no prior spectroscopic classifications. We find a total of 191 confirmed white dwarfs and 39 main-sequence…