KiDS-1000 Cosmology: machine learning -accelerated constraints on Interacting Dark Energy with CosmoPower

We derive constraints on a coupled quintessence model with pure momentum exchange from the public ∼1000 deg2 cosmic shear measurements from the Kilo-Degree Survey and the Planck 2018 Cosmic Microwave Background data. We compare this model with ΛCDM and find similar χ2 and log-evidence values. We accelerate parameter estimation by sourcing cosmological power spectra from the neural network emulator CosmoPower. We highlight the …

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Writing Scientific Papers in Astronomy

A paper has been written, about writing papers in Astronomy! It may sound ironic, but there is a lot of specialised skills going into writing in an academic style optimised to transmit scientific savoir-faire, methods, algorithms, assumptions, context of research and more. Writing papers is often one of those skills that is acquired by exposure, …

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HIFlow: Generating Diverse HI Maps Conditioned on Cosmology using Normalizing Flow

A wealth of cosmological and astrophysical information is expected from many ongoing and upcoming large-scale surveys. It is crucial to prepare for these surveys now and develop tools that can efficiently extract the maximum amount of information. We present HIFlow: a fast emulator that is able to generate neutral hydrogen (HI) maps conditioned only on …

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Exploring and interrogating astrophysical data in virtual reality

Scientists across all disciplines increasingly rely on machine learning algorithms to analyse and sort datasets of ever increasing volume and complexity. Although trends and outliers are easily extracted, careful and close inspection will still be necessary to explore and disentangle detailed behaviour, as well as identify systematics and false positives. We must therefore incorporate new …

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Rapidly quenched galaxies in the Simba cosmological simulation and observations

A wide range of mechanisms have been put forward to explain the quenching of star formation in galaxies with cosmic time, however, the true balance of responsible mechanisms remains unknown. The identification and study of galaxies that have shut down their star formation on different timescales might elucidate which mechanisms dominate at different epochs and …

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The First Large Absorption Survey in HI (FLASH): I. Science Goals and Survey Design

We describe the scientific goals and survey design of the First Large Absorption Survey in HI (FLASH), a wide field survey for 21-cm line absorption in neutral atomic hydrogen (HI) at intermediate cosmological redshifts. FLASH will be carried out with the Australian Square Kilometre Array Pathfinder (ASKAP) radio telescope and is planned to cover the …

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MIGHTEE: total intensity radio continuum imaging and the COSMOS / XMM-LSS Early Science fields

MIGHTEE is a galaxy evolution survey using simultaneous radio continuum, spectro-polarimetry, and spectral line observations from the South African MeerKAT telescope. When complete, the survey will image ∼20 deg2 over the COSMOS, E-CDFS, ELAIS-S1, and XMM-LSS extragalactic deep fields with a central frequency of 1284 MHz. These were selected based on the extensive multiwavelength datasets from numerous …

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Science Belongs To All Of Us – NSTF “Science Oscar” For Science Communicator Prof Carolina Ödman

By Nicklaus Kruger, UWC Institutional Advancement. South Africa is a country of many languages – but for many of us, “science” isn’t one of them. Astrophysicist and Associate Professor Carolina Ödman has made it her mission to translate and share the joys of science with everyone – and her efforts have earned her the coveted Communication & …

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Semi-analytic forecasts for JWST — V. AGN luminosity functions and helium reionization at z = 2-7

Active galactic nuclei (AGN) forming in the early universe are thought to be the primary source of hard ionizing photons contributing to the reionization of intergalactic helium. However, the number density and spectral properties of high-redshift AGN remain largely unconstrained. In this work, we make use of physically-informed models calibrated with a wide variety of …

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Simultaneous X-ray and radio observations of the transitional millisecond pulsar candidate CXOU J110926.4-650224. The discovery of a variable radio counterpart

We present the results of simultaneous observations of the transitional millisecond pulsar (tMSP) candidate CXOU J110926.4-650224 with the XMM-Newton satellite and the MeerKAT telescope. The source was found at an average X-ray luminosity of LX≃7×1033 erg s−1 over the 0.3-10 keV band (assuming a distance of 4 kpc) and displayed a peculiar variability pattern in the X-ray emission, …

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