codman

The Global Magneto-Ionic Medium Survey: A Faraday Depth Survey of the Northern Sky Covering 1280-1750 MHz

The Galactic interstellar medium hosts a significant magnetic field, which can be probed through the synchrotron emission produced from its interaction with relativistic electrons. Linearly polarized synchrotron emission is generated throughout the Galaxy, and at longer wavelengths, modified along nearly every path by Faraday rotation in the intervening magneto-ionic medium. Full characterization of the polarized …

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Quenching and the UVJ diagram in the SIMBA cosmological simulation

Over the past decade, rest-frame color-color diagrams have become popular tools for selecting quiescent galaxies at high redshift, breaking the color degeneracy between quiescent and dust-reddened star-forming galaxies. In this work, we study one such color-color selection tool — the rest-frame U−V vs. V−J diagram — by employing mock observations of cosmological galaxy formation simulations. In particular, we conduct …

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Gaussian Process Regression for foreground removal in HI intensity mapping experiments

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 …

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Young scientist has her eyes firmly fixed on the stars

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 …

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On the road to percent accuracy V: the non-linear power spectrum beyond ΛCDM with massive neutrinos and baryonic feedback

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 …

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First HETDEX Spectroscopic Determinations of Lyα and UV Luminosity Functions at z=2−3: Bridging a Gap Between Faint AGN and Bright Galaxies

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 …

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The environments of the radio galaxy population in SIMBA

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 …

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Postdoctoral Fellowships

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 …

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HELP: The Herschel Extragalactic Legacy Project

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 …

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Lenses In VoicE (LIVE): Searching for strong gravitational lenses in the VOICE@VST survey using Convolutional Neural Networks

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 …

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