Browsing Physics and Astronomy by Title
Now showing items 484-503 of 533
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A structure function analysis of vst-cosmos agn
(EDP Sciences, 2022)We present our sixth work in a series dedicated to variability studies of active galactic nuclei (AGN), based on the survey of the COSMOS field by the VLT Survey Telescope (VST). Its 54 r-band visits over 3.3 yr and ... -
Students' ontological security and agency in science education - an example from reasoning about the use of gene technology
(Taylor & Francis, 2013)This paper reports on a study of how students' reasoning about socioscientific issues is framed by three dynamics: societal structures, agency and how trust and security issues are handled. Examples from gene technology ... -
Superhorizon perturbations: A possible explanation of the hubble–lemaître tension and the large-scale anisotropy of the universe
(IOP Publishing, 2022)Current cosmological observations point to a serious discrepancy between the observed Hubble parameter obtained using direct versus cosmic microwave background radiation measurements. Besides this so-called Hubble– Lemaî tre ... -
Superhorizon Perturbations: A Possible Explanation of the Hubble–Lemaître Tension and the Large-scale Anisotropy of the Universe.
(The American Astronomical Society., 2022)Current cosmological observations point to a serious discrepancy between the observed Hubble parameter obtained using direct versus cosmic microwave background radiation measurements. Besides this so-called Hubble– Lemaître ... -
Surveys with small optical telescopes
(Oxford academic, 2019)odern astrophysics owes its existence to small-telescope surveys dating back to the 18th century, for example Flamsteed (1725). In the 19th century, Argelander’s survey based on visual observations with small telescopes and ... -
Synergies between intensity maps of hydrogen lines
(Oxford University Press, 2018)We study synergies between Hi 21cm and Hα intensity map observations, focusing on SKA1- like and SPHEREx-like surveys. We forecast how well such a combination can measure features in the angular power spectrum on the ... -
Synthesis and characterization of Sn‑doped TiO2 flm for antibacterial applications
(Springer, 2021)Simple sol–gel method has been exploited to deposit Sn-doped TiO2 thin flms on glass substrates. The resultant coatings were characterized by X-ray difraction (XRD), UV–visible techniques (UV–Vis), Fourier transform ... -
Synthesis and photovoltaics of novel 2,3,4,5-tetrathienylthiophene-co-poly(3-hexylthiophene-2,5-diyl) donor polymer for organic solar cell
(MPDI, 2021)This report focuses on the synthesis of novel 2,3,4,5-tetrathienylthiophene-co-poly(3-hexylthiophene-2,5-diyl) (TTT-co-P3HT) as a donor material for organic solar cells (OSCs). The properties of the synthesized TTT-co-P3HT ... -
Synthesis, characterization and ab initio study of WO3 nanocubes with peculiar electrochemical properties
(Springer, 2021)Simple sol–gel method has been exploited to deposit Sn-doped TiO2 thin flms on glass substrates. The resultant coatings were characterized by X-ray difraction (XRD), UV–visible techniques (UV–Vis), Fourier transform ... -
A systematic survey for z < 0.04 CLAGNs
(Royal Astronomical Society, 2021)We have conducted a systematic survey for z < 0.04 active Galactic nuclei (AGNs) that may have changed spectral class over the past decade. We use SkyMapper, Pan-STARRS and the V´eron-Cetty & V´eron catalogue to search ... -
Testing foundations of modern cosmology with SKA all-sky surveys
(Proceedings of Science, 2014)Continuum and HI surveys with the Square Kilometre Array (SKA) will allow us to probe some of the most fundamental assumptions of modern cosmology, including the Cosmological Principle. SKA all-sky surveys will map an ... -
Testing galaxy formation simulations with damped Lyman-α abundance and metallicity evolution
(Oxford University Press, 2020)We examine the properties of damped Lyman-α absorbers (DLAs) emerging from a single set of cosmological initial conditions in two state-of-the-art cosmological hydrodynamic simulations: SIMBA and TECHNICOLOR DAWN. The ... -
Testing gravity using large-scale redshift-space distortions
(Oxford University Press, 2013)We use luminous red galaxies from the Sloan Digital Sky Survey (SDSS) II to test the cosmological structure growth in two alternatives to the standard cold dark matter ( CDM)+general relativity (GR) cosmological model. ... -
Testing homegeneity with Galaxy Star formation histories
(IOP Publishing, 2013)Observationally confirming spatial homogeneity on sufficiently large cosmological scales is of importance to test one of the underpinning assumptions of cosmology, and is also imperative for correctly interpreting dark ... -
Testing the equivalence principle on cosmological scales using the odd multipoles of galaxy cross-power spectrum and bispectrum
(IOP, 2021)One of the cornerstones of general relativity is the equivalence principle. However, the validity of the equivalence principle has only been established on solar system scales for standard matter fields; this result ... -
Theoretical evolution of optical strong lines across cosmic time
(The American Astronomical Society, 2013)We use the chemical evolution predictions of cosmological hydrodynamic simulations with our latest theoretical stellar population synthesis, photoionization, and shock models to predict the strong line evolution of ... -
The thousand-pulsar-array programme on MeerKAT – I. Science objectives and first results
(Oxford University Press, 2020)We report here on initial results from the Thousand-Pulsar-Array (TPA) programme, part of the Large Survey Project ‘MeerTime’ on the MeerKAT telescope. The interferometer is used in the tied-array mode in the band from 856 ... -
The three hundred project: The stellar and gas profiles
(Oxford University Press, 2020)Using the catalogues of galaxy clusters from The Three Hundred project, modelled with both hydrodynamic simulations (GADGET-X and GADGET-MUSIC), and semi-analytical models (SAMs), we study the scatter and self-similarity ... -
Timing the earliest quenching events with a robust sample of massive quiescent galaxies at 2 < z < 5
(Oxford University Press, 2020-06-04)We present a sample of 151 massive (M∗ > 1010 M) quiescent galaxies at 2 <z< 5, based on a sophisticated Bayesian spectral energy distribution fitting analysis of the CANDELS UDS and GOODS-South fields. Our sample includes ... -
Torsion driven inflationary magnetogenesis
(American Physical Society, 2020)We show that the breaking of the conformal invariance of the electromagnetic Lagrangian, which is required for inflationary magnetogenesis, arises naturally in the Poincaré gauge theory. We use the minimal coupling ...