Physics and Astronomy: Recent submissions
Now showing items 181-200 of 520
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A comprehensive study of modulation effects on CMB polarization
(Springer, 2022)The Cosmic Microwave Background is characterized by temperature and linear polar ization fields. Dipole modulation in the temperature field has been extensively studied in the context of hemispherical power asymmetry. In ... -
Solar-Cycle Variability Results fromthe Solar Radiation and Climate Experiment (SORCE) Mission
(Springer, 2022)The Solar Radiation and Climate Experiment (SORCE) was a NASA mission that operated from 2003 to 2020 to provide key climate-monitoring measurements of total solar irradiance (TSI) and solar spectral irradiance (SSI). ... -
Coulomb excitation of and a change in structure approaching N = Z = 40
(American Physical Society, 2021)Background: Nuclei approaching are known to exhibit strongly deformed structures and are thought to be candidates for shape coexistence. In the krypton isotopes, are poorly characterized, preventing an understanding of ... -
The altitude of sprites observed over South Africa
(Academy of Science of South Africa, 2021)Sprites are mesospheric optical emissions that are mostly produced by large, positive cloud-to-ground lightning discharges. Sprites appear in different morphologies such as carrot, jellyfish and column, and are typically ... -
Interacting dark energy from redshift-space galaxy clustering
(IOP Publishing, 2021)Interacting dark energy models have been proposed as attractive alternatives to CDM. Forthcoming Stage-IV galaxy clustering surveys will constrain these models, but they require accurate modelling of the galaxy power ... -
The physical properties of star-forming galaxies with strong [oiii]lines at z=3.25
(IOP Publishing, 2022)We present an analysis of physical properties of 34 [O III] emission-line galaxies (ELGs) at z = 3.254 ± 0.029 in the Extended Chandra Deep Field South (ECDFS). These ELGs are selected from deep narrow H2S(1) and broad Ks ... -
The star formation rates of QSOs
(Royal Astronomical Society, 2022)We examine the far-IR properties of a sample of 5391 optically selected QSOs in the 0.5 < z < 2.65 redshift range down to log [νLν,2500(erg/s)] > 44.7, using SPIRE data from Herschel-ATLAS. We split the sample in a grid ... -
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 ...