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First ground-based observations of sprites over southern Africa
(Academy of Science of South Africa, 2018)
Sprites are the optical signatures of electrical discharges in the mesosphere triggered by large lightning
strikes associated with thunderstorms. Since their discovery in the late 1980s, sprites have been
observed ...
Predicting the neutral hydrogen content of galaxies from optical data using machine learning
(Oxford University Press, 2018)
We develop a machine learning-based framework to predict the Hi content of galaxies using
more straightforwardly observable quantities such as optical photometry and environmental
parameters. We train the algorithm on z ...
The Galactic halo pulsar population
(Oxford University Press, 2018)
Most population studies of pulsars have hitherto focused on the disc of the Galaxy, the
Galactic centre, globular clusters, and nearby galaxies. It is expected that pulsars, by
virtue of their natal kicks, are also to ...
Synergies between intensity maps of hydrogen lines
(Oxford University Press, 2018)
We study synergies between Hi 21cm and Hα intensity map observations, focusing on SKA1-
like and SPHEREx-like surveys. We forecast how well such a combination can measure features
in the angular power spectrum on the ...
The observed galaxy bispectrum from single-field inflation in the squeezed limit
(IOP Publishing, 2018)
Using the consistency relation in Fourier space, we derive the observed galaxy bispectrum from
single- eld in
ation in the squeezed limit, in which one of the three modes has a wavelength much
longer than the other two. ...
A comparison of Einstein-Boltzmann solvers for testing General Relativity
(American Physical Society, 2018)
We compare Einstein-Boltzmann solvers that include modifications to General Relativity and find that, for a
wide range of models and parameters, they agree to a high level of precision. We look at three general purpose
codes ...
The kinematic dipole in galaxy redshift surveys
(IOP Publishing, 2018)
In the concordance model of the Universe, the matter distribution { as observed in galaxy number
counts or the intensity of line emission (such as the 21cm line of neutral hydrogen) - should have
a kinematic dipole due ...
Investigation of excited 0+ states in 160Er populated via the (p, t) two-neutron transfer reaction
(EDP Sciences, 2018)
Many efforts have been made in nuclear structure physics to interpret the nature of low-lying excited 0+ states in well-deformed rare-earth nuclei. However, one of the difficulties in resolving the nature of these states ...
Aligned metal absorbers and the ultraviolet background at the end of reionization
(Oxford University Press, 2018)
We use observations of spatially-aligned C ii, C iv, Si ii, Si iv, and O i absorbers to probe the
slope and intensity of the ultraviolet background (UVB) at z ∼ 6. We accom- plish this by comparing
observations with ...
Diurnal variations in global Joule heating morphology and magnitude due to neutral winds.
(Wiley, 2018)
In the polar ionosphere, variations in Joule heating are significantly controlled by changes in
plasma convection, such as that brought about by changes in the interplanetary magnetic field. However,
another important ...