Search Publications
H0LiCOW - XIII. A 2.4 per cent measurement of H0 from lensed quasars: 5.3σ tension between early- and late-Universe probes
Treu, Tommaso; Marshall, Philip J.; Sonnenfeld, Alessandro +23 more
We present a measurement of the Hubble constant (H0) and other cosmological parameters from a joint analysis of six gravitationally lensed quasars with measured time delays. All lenses except the first are analysed blindly with respect to the cosmological parameters. In a flat Λ cold dark matter (ΛCDM) cosmology, we find $H_{0} = 73.3_{…
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(…
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…
H0LiCOW XII. Lens mass model of WFI2033-4723 and blind measurement of its time-delay distance and H0
Treu, Tommaso; Marshall, Philip J.; Sonnenfeld, Alessandro +15 more
We present the lens mass model of the quadruply-imaged gravitationally lensed quasar WFI2033 - 4723, and perform a blind cosmographical analysis based on this system. Our analysis combines (1) time-delay measurements from 14 yr of data obtained by the COSmological MOnitoring of GRAvItational Lenses (COSMOGRAIL) collaboration, (2) high-resolution H…
Observing the tail of reionization: neutral islands in the z = 5.5 Lyman-α forest
Nasir, Fahad; D'Aloisio, Anson
Previous studies have noted difficulties in modelling the highest opacities of the z > 5.5 Ly α forest, epitomized by the extreme Lyα trough observed towards quasar ULAS J0148 + 0600. One possibility is that the most opaque regions at these redshifts contain significant amounts of neutral hydrogen. This explanation, which abandons the common as…
Ionizing the intergalactic medium by star clusters: the first empirical evidence
Giavalisco, M.; Castellano, M.; Gilli, R. +14 more
We present a VLT/X-Shooter spectroscopy of the Lyman continuum (LyC) emitting galaxy Ion2 at z = 3.2121 and compare it to that of the recently discovered strongly lensed LyC emitter at z = 2.37, known as the Sunburst arc. Three main results emerge from the X-Shooter spectrum: (a) the Ly α has three distinct peaks with the central one at the system…
The Milky Way's disc of classical satellite galaxies in light of Gaia DR2
Kroupa, Pavel; Pawlowski, Marcel S.
We study the correlation of orbital poles of the 11 classical satellite galaxies of the Milky Way, comparing results from previous proper motions with the independent data by Gaia DR2. Previous results on the degree of correlation and its significance are confirmed by the new data. A majority of the satellites co-orbit along the Vast Polar Structu…
Weighing the stellar constituents of the galactic halo with APOGEE red giant stars
Bovy, Jo; Mackereth, J. Ted
The stellar mass in the halo of the Milky Way is notoriously difficult to determine, owing to the paucity of its stars in the solar neighbourhood. With tentative evidence from Gaia that the nearby stellar halo is dominated by a massive accretion event - referred to as Gaia-Enceladus or Sausage - these constraints are now increasingly urgent. We me…