Physics and Astronomy: Recent submissions
Now showing items 201-220 of 533
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Can Galaxy Evolution Mimic Cosmic Reionization?
(IOP Publishing, 2021)Lyα emitting galaxies are powerful tools to probe the late stages of cosmic reionization. The observed sudden drop in Lyα fraction at z > 6 is often interpreted as a sign of reionization, since the intergalactic medium ... -
Multi-scale perturbation theory II: Solutions and leading-order bispectrum in the ΛcDM universe
(IOP Publishing, 2021)Two-parameter perturbation theory (2PPT) is a framework designed to include the relativistic gravitational effects of small-scale nonlinear structures on the large-scale properties of the Universe. In this paper we use ... -
The redshift evolution of the baryonic Tully-Fisher relation in SIMBA
(Oxford university press, 2021)The baryonic Tully–Fisher relation (BTFR) is an important tool for constraining galaxy evolution models. As 21-cm HI emission studies have been largely restricted to low redshifts, the redshift evolution of the BTFR is ... -
Corrosion improvement of 304l stainless steel by zrsin and zrsi(N,o) mono-and double-layers prepared by reactive cathodic arc evaporation
(MDPI, 2021)Zr-based nitrides and oxynitrides were deposited by reactive cathodic arc evaporation in monolayer and double-layer structures with the aim of increasing the corrosion protection of 304L stainless steel (SS) in a biomedical ... -
High-precision half-life determination of 14O via direct β counting
(Springer, 2022)The half-life of the superallowed Fermi β+ emitter 14O was determined to high precision via a direct β counting experiment performed at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF. The result, T1/2( 14O) ... -
Simulations of primary beam effects on the cosmic bispectrum phase observed with the Hydrogen Epoch of Reionization Array
(Royal Astronomical Society, 2022)The 21 cm transition from neutral hydrogen promises to be the best observational probe of the epoch of reionization (EoR). The main difficulty in measuring the 21 cm signal is the presence of bright foregrounds that require ... -
Practical galaxy morphology tools from deep supervised representation learning
(Oxford University Press, 2022)Astronomers have typically set out to solve supervised machine learning problems by creating their own representations from scratch. We show that deep learning models trained to answer every Galaxy Zoo DECaLS question ... -
MIGHTEE-Hi: The relation between the Hi gas in galaxies and the cosmic web
(Oxford University Press, 2022)We study the 3D axis of rotation (3D spin) of 77 Hi galaxies from the MIGHTEE-Hi Early Science observations, and its relation to the filaments of the cosmic web. For this Hi-selected sample, the alignment between the spin ... -
Estimating the electron energy and the strength of the electric field within sprites using ground-based optical data observed over South African storms
(Elsevier, 2021)We present a new simplified method to estimate the characteristic electron energy and electric field within a mesospheric transient luminous event using ground-based calibrated and filtered optical data. We assume ... -
Pks 1830-211: oh and hi at z = 0.89 and the first meerkat uhf spectrum
(EDP Sciences, 2021)The Large Survey Project (LSP) "MeerKAT Absorption Line Survey"(MALS) is a blind H I 21 cm and OH 18 cm absorption line survey in the L- and UHF-bands, primarily designed to better determine the occurrence of atomic and ... -
Measuring the HI mass function below the detection threshold
(Royal Astronomical Society, 2020)We present a Bayesian stacking technique to directly measure the H I mass function (HIMF) and its evolution with redshift using galaxies formally below the nominal detection threshold. We generate galaxy samples over several ... -
Hi global scaling relations in the wise-whisp survey
(Oxford University Press, 2021)We present the global scaling relations between the neutral atomic hydrogen gas, the stellar disk and the star forming disk in a sample of 228 nearby galaxies that are both spatially and spectrally resolved in HI line ... -
Big data research infrastructure collaboration toward the SKA (BRICSKA)
(Academia Brasileira de Ciencias, 2021)Astronomy is entering an era of mega-data that will render conventional research methods as well as data and visual analytics tools ineffective. The Square Kilometre Array (SKA) drives one of the most significant big ... -
Quantifying and incentivizing exploration of reputable sources for argument formation in an online discussion forum
(Academic Conferences and Publishing International Limited, 2021)Nuclearpowerformspartofthefirst-yearphysicsundergraduatecourseworkinthe extended curriculum program at the University of the Western Cape. This investigation intendstoassiststudentsinmasteringtheirunderstandingof ... -
First Observations of E-Region Near Range Echoes Partially Modulated by F-Region Traveling Ionospheric Disturbances Observed by the Same SuperDARN HF Radar
(Journal of Geophysical Research: Space Physics, 2022)We present the first observations from SuperDARN HF radar data of E-region Near Range Echoes (NREs) whose amplitudes are partially modulated by Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) propagating in the ... -
Assessing accessibility and availability of portable water supply in selected communities of Lepelle-Nkumpi local municipality, Limpopo province of South Africa
(elsevier, 2022)In this study, we assessed the accessibility and availability of portable water supply in selected communities of the Lepelle-Nkumpi Local Municipality. A systematic random sampling method was used to select 49 households ... -
Deep extragalactic visible legacy survey (DEVILS):Evolution of the σsFR-M relation and implications for self-regulated star formation
(University of the Western Cape, 2022)We present the evolution of the star formation dispersion–stellar mass relation ( σSFR –M ) in the DEVILS D10 region using new measurements derived using the PROSPECT spectral energy distribution fitting code. We find ... -
COSMOS2020: A panchromatic view of the universe to z ∼ 10 from two complementary catalogs
(University of the Western Cape, 2022)The Cosmic Evolution Survey (COSMOS) has become a cornerstone of extragalactic astronomy. Since the last public catalog in 2015, a wealth of new imaging and spectroscopic data have been collected in the COSMOS field. This ... -
Probing the nature of the conjectured low-spin wobbling bands in atomic nuclei
(Elsevier, 2022)The precession of an atomic nucleus can be approximately described as wobbling motion, arising from the coupling of a rotation and a harmonic vibration. Recently, a number of wobbling bands were reported at low spin, which ... -
Multimodality and new materialism in science learning: Exploring insights from an introductory physics lesson
(Unisa Press, 2021)Science disciplines are inherently multimodal, involving written and spoken language, bodily gestures, symbols, diagrams, sketches, simulation and mathematical formalism. Studies have shown that ...