Search Publications
STRIDES: a 3.9 per cent measurement of the Hubble constant from the strong lens system DES J0408-5354
Bechtol, K.; Smith, M.; Finley, D. A. +88 more
We present a blind time-delay cosmographic analysis for the lens system DES J0408-5354. This system is extraordinary for the presence of two sets of multiple images at different redshifts, which provide the opportunity to obtain more information at the cost of increased modelling complexity with respect to previously analysed systems. We perform d…
A lack of evolution in the very bright end of the galaxy luminosity function from z ≃ 8 to 10
Bowler, R. A. A.; McLure, R. J.; Dunlop, J. S. +5 more
We utilize deep near-infrared survey data from the UltraVISTA fourth data release (DR4) and the VIDEO survey, in combination with overlapping optical and Spitzer data, to search for bright star-forming galaxies at z ≳ 7.5. Using a full photometric redshift fitting analysis applied to the ∼6 deg^2 of imaging searched, we find 27 Lyman break galaxie…
The MOSDEF survey: direct-method metallicities and ISM conditions at z ∼ 1.5-3.5
Barro, Guillermo; Siana, Brian; Shapley, Alice E. +14 more
We present detections of [O III] λ4363 and direct-method metallicities for star-forming galaxies at z = 1.7-3.6. We combine new measurements from the MOSFIRE Deep Evolution Field (MOSDEF) survey with literature sources to construct a sample of 18 galaxies with direct-method metallicities at z > 1, spanning 7.5 < 12+log(O/H) < 8.2 and log(…
A Volume-limited Sample of Cataclysmic Variables from Gaia DR2: Space Density and Population Properties
Knigge, C.; Hermes, J. J.; Gänsicke, B. T. +15 more
We present the first volume-limited sample of cataclysmic variables (CVs), selected using the accurate parallaxes provided by the second data release (DR2) of the European Space Agency Gaia space mission. The sample is composed of 42 CVs within 150 pc, including two new systems discovered using the Gaia data, and is $(77 \pm 10)$ per cent complete…
A new mass-loss rate prescription for red supergiants
Smith, Nathan; Gehrz, Robert D.; van Loon, Jacco Th +3 more
Evolutionary models have shown the substantial effect that strong mass-loss rates ( $\dot{M}$ s) can have on the fate of massive stars. Red supergiant (RSG) mass-loss is poorly understood theoretically, and so stellar models rely on purely empirical $\dot{M}$ -luminosity relations to calculate evolution. Empirical prescriptions usually scale with …
Reverse engineering the Milky Way
Forbes, Duncan A.
The ages, metallicities, alpha-elements, and integrals of motion of globular clusters (GCs) accreted by the Milky Way from disrupted satellites remain largely unchanged over time. Here we have used these conserved properties in combination to assign 76 GCs to five progenitor satellite galaxies - one of which we dub the Koala dwarf galaxy. We fit a…
Constraining the thermally pulsing asymptotic giant branch phase with resolved stellar populations in the Large Magellanic Cloud
Boyer, Martha L.; Girardi, Léo; de Grijs, Richard +18 more
Reliable models of the thermally pulsing asymptotic giant branch (TP-AGB) phase are of critical importance across astrophysics, including our interpretation of the spectral energy distribution of galaxies, cosmic dust production, and enrichment of the interstellar medium. With the aim of improving sets of stellar isochrones that include a detailed…
ALMA uncovers the [C II] emission and warm dust continuum in a z = 8.31 Lyman break galaxy
Shibuya, Takatoshi; Inoue, Akio K.; Hashimoto, Takuya +15 more
We report on the detection of the [C II] 157.7 µm emission from the Lyman break galaxy (LBG) MACS0416_Y1 at z = 8.3113, by using the Atacama Large Millimeter/submillimeter Array (ALMA). The luminosity ratio of [O III] 88 µm (from previous campaigns) to [C II] is 9.3 ± 2.6, indicative of hard interstellar radiation fields and/or a low c…
Ages and kinematics of chemically selected, accreted Milky Way halo stars
Hawkins, Keith; Jofré, Paula; Das, Payel
We exploit the [Mg/Mn]-[Al/Fe] chemical abundance plane to help identify nearby halo stars in the 14th data release from the APOGEE survey that have been accreted on to the Milky Way. Applying a Gaussian Mixture Model, we find a `blob' of 856 likely accreted stars, with a low disc contamination rate of ∼7 per cent. Cross-matching the sa…
Gravity-mode period spacings and near-core rotation rates of 611 γ Doradus stars with Kepler
Li, Gang; Bedding, Timothy R.; Antoci, Victoria +4 more
We report our survey of γ Dor stars from the 4-yr Kepler mission. These stars pulsate mainly in g modes and r modes, showing period-spacing patterns in the amplitude spectra. The period-spacing patterns are sensitive to the chemical composition gradients and the near-core rotation, hence they are essential for understanding the stellar interior. W…