Physics and Astronomy: Recent submissions
Now showing items 441-460 of 520
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Extending BEAMS to incorporate correlated systematic uncertainties
(IOP Science, 2013)New supernova surveys such as the Dark Energy Survey, Pan-STARRS and the LSST will produce an unprecedented number of photometric supernova candidates, most with no spectroscopic data. Avoiding biases in cosmological ... -
Evolution of faint radio sources in the VIDEO-XMM3 field
(OUP, 2013)It has been speculated that low luminosity radio-loud AGN have the potential to serve as an important source of AGN feedback, and may be responsible for suppressing star-formation activity in massive elliptical galaxies ... -
Cosmology with photometrically classified type IA supernovae from the SDSS-II supernova survey
(The American Astronomical Society, 2013)We present the cosmological analysis of 752 photometrically–classified Type Ia Supernovae (SNe Ia) obtained from the full Sloan Digital Sky Survey II (SDSS-II) Supernova (SN) Survey, supplemented with host–galaxy ... -
EC 10246-2707: a new eclipsing sdB + M dwarf binary⋆
(OUP, 2013)We announce the discovery of a new eclipsing hot subdwarf B + M dwarf binary, EC 10246-2707, and present multi-colour photometric and spectroscopic observations of this system. Similar to other HW Vir-type binaries, the ... -
Evolution of star formation in the UKIDSS ultra deep survey field - I. Luminosity functions and cosmic star formation rate out of z = 1.6
(OUP, 2013)We present new results on the cosmic star formation history in the SXDS-UDS field out to z = 1.6. We compile narrow-band data from the Subaru Telescope and the Visible and Infrared Survey Telescope for Astronomy (VISTA) ... -
Constraining the bright-end of the UV luminosity function for z ~ 7-9 galaxies: results from CANDELS/GOODS-South
(OUP, 2013)The recent Hubble Space Telescope near-infrared imaging with the Wide-Field Camera #3 (WFC3) of the GOODS-South field in the CANDELS program covering nearly 100 arcmin2, along with already existing Advanced Camera for ... -
Cosmology on ultralarge scales with intensity mapping of the neutral hydrogen 21 cm emission: limits on primodial non-gaussianity
(American Physical Society, 2013)The large-scale structure of the Universe supplies crucial information about the physical processes at play at early times. Unresolved maps of the intensity of 21 cm emission from neutral hydrogen HI at redshifts z ~ 1 − ... -
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 ...