Browsing Research Articles (Physics) by Title
Now showing items 21-40 of 497
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Asteroseismology of Massive Stars with the TESS Mission: The Runaway β Cep Pulsator PHL 346 = HN Aqr
(The Astrophysical journal letter, 2019)We report an analysis of the first known β Cep pulsator observed by the Transiting Exoplanet Survey Satellite (TESS) mission, the runaway star PHL 346 = HN Aqr. The star, previously known as a singly periodic pulsator, has ... -
Astronomy for Development – A story from South Africa
(UWC, 2021)In this article we describe the recent history of astronomy in South Africa from the perspective of development. We describe how all major astronomy initiatives have carried a component of development with them, be it ... -
Augmenting machine learning photometric redshifts with Gaussian mixture models
(Oxford University Press, 2020-09-11)Wide-area imaging surveys are one of the key ways of advancing our understanding of cosmology, galaxy formation physics, and the large-scale structure of the Universe in the coming years. These surveys typically require ... -
Automated detection of antenna malfunctions in large-n interferometers: A case study with the hydrogen epoch of reionization array
(2022)We present a framework for identifying and flagging malfunctioning antennas in large radio interferometers. We outline two distinct categories of metrics designed to detect outliers along known failure modes of large ... -
The baryonic Tully–Fisher relation in the SIMBA simulation
(Oxford University Press, 2020)We investigate the Baryonic Tully–Fisher relation (BTFR) in the (100h−1Mpc)3SIMBA hydrodynamical galaxy formation simulation together with a higher resolution (25h−1Mpc)3SIMBA run, for over 10 000 disc-dominated, H I-rich ... -
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 ... -
Bio-synthesised black α-Cr2O3 nanoparticles; experimental analysis and density function theory calculations
(Elsevier, 2021)A selective single phase black α-Cr2O3 nanoparticles was bio-synthesised via simple straight-forward green synthesis approach. The process involves extraction of phytochemicals contained in peels of sweet potatoes. Extraction ... -
Black hole - galaxy correlations without self-regulation
(American Astronomical Society, 2013)Recent models of black hole growth in a cosmological context have forwarded a paradigm in which the growth is self-regulated by feedback from the black hole itself. Here we use cosmological zoom simulations of galaxy formation ... -
Breaking baryon-cosmology degeneracy with the electron density power spectrum
(IOP Publishing, 2022)Uncertain feedback processes in galaxies affect the distribution of matter, currently limiting the power of weak lensing surveys. If we can identify cosmological statistics that are robust against these uncertainties, or ... -
The bright extragalactic ALMA redshift survey (BEARS) – II. Millimetre photometry of gravitational lens candidates
(Oxford University Press, 2023)We present 101- and 151-GHz ALMA continuum images for 85 fields selected from Herschel observations that have 500-μm flux densities >80 mJy and 250–500-μm colours consistent with z > 2, most of which are expected to be ... -
Bringing together knowledge and capabilities: a case study of engineering graduates
(Springer Verlag, 2016)In contemporary times there is a renewed focus on the purposes of university education in science or engineering, especially inemerging economycontexts like South Africa where the massification of higher education is in ... -
Broad-band radio polarimetry of disc galaxies and AGN with KAT-7
(Oxford University Press, 2020-10-24)We report broad-band (1.2–1.9 GHz) radio continuum observations at arcminute resolutions of two nearby disc galaxies, NGC 1808 and NGC 1097, and four active galactic nuclei (AGN)-powered radio sources: PKS B1934−638, PKS ... -
Calibrating photometric redshifts with intensity mapping observations
(American Physical Society, 2017)Imaging surveys of galaxies will have a high number density and angular resolution yet a poor redshift precision. Intensity maps of neutral hydrogen (HI) will have accurate redshift resolution yet will not resolve ... -
Calibrating the James Webb Space telescope filters as star formation rate indicators
(American Astronomical Society, 2018)We have calibrated the 6.5m James Webb Space Telescope (JWST) mid-infrared (MIR) filters as star formation rate (SFR) indicators, using JWST photometry synthesized from Spitzer spectra of 49 low-redshift galaxies, which ... -
The CAMELS multifield data set: Learning the universe’s fundamental parameters with artificial intelligence
(IOP, 2022)We present the Cosmology and Astrophysics with Machine Learning Simulations (CAMELS) Multifield Data set (CMD), a collection of hundreds of thousands of 2D maps and 3D grids containing many different properties of cosmic ... -
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 ... -
Ceers key paper. I. An early look into the first 500myr of galaxy formation with jwst
(American Astronomical Society, 2023)We present an investigation into the first 500 Myr of galaxy evolution from the Cosmic Evolution Early Release Science (CEERS) survey. CEERS, one of 13 JWST ERS programs, targets galaxy formation from z ∼ 0.5 to >10 using ... -
A census of the pulsar population observed with the international LOFAR station FR606 at low frequencies (25–80 MHz)
(EDP Sciences, 2020)ontext. To date, only 69 pulsars have been identified with a detected pulsed radio emission below 100 MHz. A LOFAR-core LBA census and a dedicated campaign with the Nançay LOFAR station in stand-alone mode were carried out ... -
Ceria-Spiderweb Nanosheets Unlock the Energy-Storage Properties in the “Sleeping” Triplite (Mn2(PO4)F)
(American Chemical Society, 2021)Rechargeable aqueous mobile-ion batteries (RAMIBs) are attractive next-generation battery technologies. Manganese fluorophosphate (triplite), Mn2(PO4)F (MFP), and its ceria- and carbon-coated composites (i.e., MFP-CeO2 and ... -
A CHANDRA STUDY OF TEMPERATURE SUBSTRUCTURES IN INTERMEDIATE-REDSHIFT GALAXY CLUSTERS
(2009)By analyzing the gas temperature maps created from the Chandra archive data, we reveal the prevailing existence of temperature substructures on ∼ 100 h −1 70 kpc scales in the central regions of nine intermediate-redshift ...
