Siyambonga Matshawule

HONOURS SCHOLARSHIPS FOR 2024 CENTRE FOR RADIO COSMOLOGY UNIVERSITY OF THE WESTERN CAPE DEADLINE: 16 October 2023

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The Centre for Radio Cosmology (CRC) in the Department of Physics & Astronomy at UWC isinternationally recognised for its research in cosmology and galaxy evolution with MeerKAT, theSquare Kilometre Array (SKA) and other telescopes (see astro.uwc.ac.za for further details). In 2023, the CRC research team includes 24 PhD/ MSc students and 11 postdoctoral fellows.Postgraduate students …

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Halo Scaling Relations and Hydrostatic Mass Bias in the Simba Simulation From Realistic Mock X-ray Catalogues

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We present a new end-to-end pipeline for Mock Observations of X-ray Halos and Analysis (MOXHA) for hydrodynamic simulations of massive halos, and use it to investigate X-ray scaling relations and hydrostatic mass bias in the Simba cosmological hydrodynamic simulation for halos with ?500 ∼ 1013−15 ?⊙ . MOXHA ties together existing yT-based software packages and …

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The HI intensity mapping power spectrum: insights from recent measurements

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The first direct measurements of the HI intensity mapping power spectrum were recently made using the MeerKAT telescope. These measurements are on nonlinear scales, at redshifts 0.32 and 0.44. We develop a formalism for modelling small-scale power in redshift space, within the context of the mass-weighted HI halo model framework. This model is consistent with …

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MeerKLASS simulations: Mitigating 1/f noise for auto-correlation intensity mapping measurements

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We present and compare several methods to mitigate time-correlated (1/f) noise within the HI intensity mapping component of the MeerKAT Large Area Synoptic Survey (MeerKLASS). By simulating scan strategies, the HI signal, white and correlated noise, we assess the ability of various data processing pipelines to recover the power spectrum of HI brightness temperature fluctuations. …

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MSc AND PhD SCHOLARSHIPS FOR 2024 CENTRE FOR RADIO COSMOLOGY UNIVERSITY OF THE WESTERN CAPE DEADLINE: 5 June 2023

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The Centre for Radio Cosmology (CRC) at UWC is internationally recognised for its research in cosmology and galaxy evolution with MeerKAT, the Square Kilometre Array (SKA) and other telescopes (see astro.uwc.ac.za for further details). In 2023, the CRC research team includes 24 PhD/ MSc students and 11 postdoctoral fellows. Postgraduate students at the CRC work …

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The bright end of the galaxy luminosity function at z≃7 from the VISTA VIDEO survey

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We have conducted a search for z≃7 Lyman break galaxies over 8.2 square degrees of near-infrared imaging from the VISTA Deep Extragalactic Observations (VIDEO) survey in the XMM-Newton – Large Scale Structure (XMM-LSS) and the Extended Chandra Deep Field South (ECDF-S) fields. Candidate galaxies were selected from a full photometric redshift analysis down to a Y+J depth of 25.3 …

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The HI in Ring Galaxies Survey (HI-RINGS) — Effects of the bar on the HI gas in ring galaxies

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We present a new high-resolution neutral atomic hydrogen (HI) survey of ring galaxies using the Australia Telescope Compact Array (ATCA). We target a sample of 24 ring galaxies from the Buta (1995) Southern Ring Galaxy Survey Catalogue in order to study the origin of resonance-, collisional- and interaction-driven ring galaxies. In this work, we present …

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Physics-informed neural networks in the recreation of hydrodynamic simulations from dark matter

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Physics-informed neural networks have emerged as a coherent framework for building predictive models that combine statistical patterns with domain knowledge. The underlying notion is to enrich the optimization loss function with known relationships to constrain the space of possible solutions. Hydrodynamic simulations are a core constituent of modern cosmology, while the required computations are both …

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CEERS Key Paper VI: JWST/MIRI Uncovers a Large Population of Obscured AGN at High Redshifts

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Mid-infrared observations are powerful in identifying heavily obscured Active Galactic Nuclei (AGN) which have weak emission in other wavelengths. The Mid-Infrared Instrument (MIRI) onboard JWST offers an excellent chance to perform such studies. We take advantage of the MIRI imaging data from the Cosmic Evolution Early Release Science Survey (CEERS) to investigate the AGN population …

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Emulating radiation transport on cosmological scale using a denoising Unet

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Semi-numerical simulations are the leading candidates for evolving reionization on cosmological scales. These semi-numerical models are efficient in generating large-scale maps of the 21cm signal, but they are too slow to enable inference at the field level. We present different strategies to train a U-Net to accelerate these simulations. We derive the ionization field directly …

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