Physics and Astronomy: Recent submissions
Now showing items 461-480 of 533
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Comparison of Hi and optical redshifts of galaxies - The impact of redshift uncertainties on spectral line stacking
(Oxford University Press, 2013)Accurate optical redshifts will be critical for spectral co-adding techniques used to extract detections from below the noise level in ongoing and upcoming surveys for Hi, which will extend our current understanding of ... -
Constraints on anisotropic cosmic expansion from supernovae
(Edp Sciences, 2013)AIMS. We test the isotropy of the expansion of the Universe by estimating the hemispherical anisotropy of supernova type Ia (SN Ia) Hubble diagrams at low redshifts (z < 0.2). METHODS. We compare the best fit Hubble ... -
Clustering of quintessence on horizon scales and its imprint on HI intensity mapping
(IOP Science, 2013)Quintessence can cluster only on horizon scales. What is the effect on the observed matter distribution? To answer this, we need a relativistic approach that goes beyond the standard Newtonian calculation and deals properly ... -
Anti-lensing: the bright side of voids
(American Physical Society, 2013)More than half of the volume of our Universe is occupied by cosmic voids. The lensing magni ca- tion e ect from those under-dense regions is generally thought to give a small dimming contribution: objects on the far side ... -
Mining the Herschel-Astrophysical Terahertz Large Area Survey: submillimetre-selected blazars in equatorial fields
(Oxford University Press, 2013)The Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) provides an unprecedented opportunity to search for blazars at sub-mm wavelengths. We cross-matched the Faint Images of the Radio Sky at Twenty-cm (FIRST) ... -
Physical properties of spectroscopically confirmed galaxies at Z ≥ 6. I. Basic characteristics of the rest-frame UV continuum and lyman-alpha emission
(American Astronomical Society, 2013)We present deep HST near-IR and Spitzer mid-IR observations of a large sample of spectroscopically- confirmed galaxies at z ≥ 6. The sample consists of 51 Ly-alpha emitters (LAEs) at z ≃ 5.7, 6.5, and 7.0, and 16 Lyman-break ... -
An overview of the Dwarf Galaxy Survey
(The Astronomical Society of the Pacific, 2013)The Dwarf Galaxy Survey (DGS) program is studying low-metallicity galax- ies using 230h of far-infrared (FIR) and submillimetre (submm) photometric and spectroscopic observations of the Herschel Space Observatory and ... -
Comparative study: the effect of annealing conditions on the properties of P3HT:PCBM blends
(Springer Verlag, 2013)This paper presents a detailed study on the role of various annealing treatments on organic poly(3-hexylthiophene) and [6]-phenyl-C61-butyric acid methyl ester blends under different experimental conditions. A combination ... -
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 ... -
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 ... -
Annealing effect of hybrid solar cells based on poly (3-hexylthiophene) and zinc-oxide nanostructures
(Elsevier, 2013)The structural growth and optical and photovoltaic properties of the organic–inorganic hybrid structures of zinc oxide (ZnO)-nanorods/poly-3-hexylthiophene (P3HT) and two variations of organic polymer blends of ZnO/ ... -
Inelastic scattering of 9Li and excitation mechanism of its first excited state
(Elsevier, 2013)The first measurement of inelastic scattering of 9Li from deuterons at the ISAC facility is reported. The measured angular distribution for the first excited state confirms the nature of excitation to be an E2 transition. ... -
Investigations on the characterization of ion implanted hexagonal boran nitride
(Elsevier, 2013)The effect of ion implantation on hexagonal boron nitride (h-BN) is studied herein. We use boron as an ion of choice to introduce radiation damage into h-BN, at fluences ranging from 1 x 10 14–1 x 10 16 ions/cm2 and ... -
Periodic variations in the O-C diagrams of five pulsation frequencies of the DB white dwarf EC 20058-5234
(American Physical Society, 2013)Variations in the pulsation arrival time of five independent pulsation frequencies of the DB white dwarf EC 20058−5234 individually imitate the effects of reflex motion induced by a planet or companion but are inconsistent ... -
Probing reionization with LOFAR (Low Frequency Array) using 21-cm redshift space distortions
(Oxford University Press, 2013)One of the most promising ways to study the epoch of reionization (EoR) is through radio observations of the redshifted 21-cm line emission from neutral hydrogen. These observations are complicated by the fact that the ... -
Probing the bias of radio sources at high redshift
(Oxford University Press, 2013)The relationship between the clustering of dark matter and that of luminous matter is often described using the bias parameter. Here, we provide a new method to probe the bias of intermediate-to-high-redshift radio ... -
Properties of Type Ia supernovae inside rich galaxy clusters
(Oxford University Press, 2013)We used the Gaussian Mixture Brightest Cluster Galaxy catalogue and Sloan Digital Sky Survey-II supernovae data with redshifts measured by the Baryon Oscillation Spectroscopic Survey to identify 48 Type Ia supernovae ... -
Radio-loud active calactic nucleus: is there a link between luminosity and cluster environment?
(American Physical Society, 2013)We present here the first results from the Chandra ERA (Environments of Radio-loud AGN) Large Project, characterizing the cluster environments of a sample of 26 radio-loud active galactic nuclei (AGNs) at z ∼ 0.5 that ... -
Revised SWIRE photometric redshifts
(Oxford University Press, 2013)We have revised the Spitzer Wide-Area Infrared Extragalactic survey (SWIRE) Photometric Redshift Catalogue to take account of new optical photometry in several of the SWIRE areas, and incorporating Two Micron All Sky ... -
Sample variance, source clustering and their influence on the counts of faint radio sources
(Oxford University Press, 2013)The shape of the curves defined by the counts of radio sources per unit area as a function of their flux density was one of the earliest cosmological probes. Radio source counts continue to be an area of astrophysical ...
