We apply for the first time Gaussian Process Regression (GPR) as a foreground removal technique in the context of single-dish, low redshift HI intensity mapping, and present an open-source python toolkit for doing so. We use MeerKAT and SKA1-MID-like simulations of 21cm foregrounds (including polarisation leakage), HI cosmological signal and instrumental noise. We find that …
Astrophysics student Nicole Thomas, who is completing her PhD at the University of the Western Cape’s Department of Physics and Astronomy, was selected to attend the 69th Nobel Laureate Meeting in Lindau, Germany, in 2019. Nicole, one of our students, is interviewed in UWC’s latest 360º Perspectives Magazine (p.24-25) – a big issue packed with retrospectives and …
In the context of forthcoming galaxy surveys, to ensure unbiased constraints on cosmology and gravity when using non-linear structure information, percent-level accuracy is required when modelling the power spectrum. This calls for frameworks that can accurately capture the relevant physical effects, while allowing for deviations from ΛCDM. Massive neutrino and baryonic physics are two of the …
We present Lyα and ultraviolet-continuum (UV) luminosity functions (LFs) of galaxies and active galactic nuclei (AGN) at z=2.0−3.5 determined by the un-targetted optical spectroscopic survey of the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). We combine deep Subaru imaging with HETDEX spectra resulting in 11.4 deg2 of fiber-spectra sky coverage, obtaining 18320 galaxies spectroscopically identified with Lyα emission, 2126 of which host type 1 AGN showing broad …
We investigate the environmental properties of the radio galaxy population using the Simba cosmological hydrodynamic simulation. We identify centrals and satellites from a population of high and low excitation radio galaxies (HERGs and LERGs) in Simba, and study their global properties. We find that ∼20% of radio galaxies are satellites and that there are insignificant differences in …
The Centre for Radio Cosmology (CRC) at UWC is internationally recognised for its research in cosmology using MeerKAT, the Square Kilometre Array (SKA) and other radio and optical/IR telescopes. CRC faculty are involved in MeerKAT and SKA key science, as well as in HERA, HIRAX and the Rubin Observatory (LSST). In 2021, the UWC Astro …
We present the Herschel Extragalactic Legacy Project (HELP). This project collates, curates, homogenises, and creates derived data products for most of the premium multi-wavelength extragalactic data sets. The sky boundaries for the first data release cover 1270 deg2 defined by the Herschel SPIRE extragalactic survey fields; notably the Herschel Multi-tiered Extragalactic Survey (HerMES) and the …
We present a sample of 16 likely strong gravitational lenses identified in the VST Optical Imaging of the CDFS and ES1 fields (VOICE survey) using Convolutional Neural Networks (CNNs). We train two different CNNs on composite images produced by superimposing simulated gravitational arcs on real Luminous Red Galaxies observed in VOICE. Specifically, the first CNN …
The National Science and Technology Forum awards were established decades ago to recognise outstanding contributions to science. The University of the Western Cape (UWC) is once again playing its part, with three top UWC scientists being nominated for the 2020/2021 NSTF-South32 Awards. “We are living in interesting and unprecedented times,” said Professor Michael-Davies-Coleman, Dean of UWC’s Faculty …
A new preprint by Louis Perenon, Matteo Martinelli, Stéphane Ilić, Roy Maartens, Michelle Lochner and Chris Clarkson has been posted on the arXiv. Read the abstract below. Next-generation large-scale structure surveys will deliver a significant increase in the precision of growth data, allowing us to use `agnostic’ methods to study the evolution of perturbations without …
