Browsing Research Articles (Physics) by Issue Date

Now showing items 1-20 of 497

    • Promoting physics and development in Africa 

      Zingu, Edmund (American Institute of Physics, 2004)
      To excel in physics research in Africa is to conquer Mount Everest without the aid of additional oxygen. In a continent that lacks the infrastructure of research laboratories, technical support, and so forth, relatively ...

    • Figure rotation of dark haloes in cold dark matter simulations 

      Bryan, Scott E.; Cress, Christine M (Oxford University Press, 2007)
      We investigate the figure rotation of dark matter haloes identified in cold dark matter (CDM) simulations.We find that when strict criteria are used to select suitable haloes for study, five of the 222 haloes identified ...

    • A CHANDRA STUDY OF TEMPERATURE SUBSTRUCTURES IN INTERMEDIATE-REDSHIFT GALAXY CLUSTERS 

      Gu, Liyi; Wang, Yu; Zhang, Zhongli (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 ...

    • Relativistic mean field formulation of clustering in heavy nuclei 

      S.M. Wyngaardt; H. W. Groenewald; T.T Ibrahim; J. Ndayishimye; S.M. Perez (IOP, 2010)
      Very little is known about clustering in heavy nuclei and in particular the interaction between the correlated cluster nucleons and remaining core nucleons. Currently the phenomenological Saxon-Woods plus cubic Saxon-Woods ...

    • The orbital periods of aa dor and ny vir 

      Kilkenny, Dave (Oxford University Press, 2011)
      New timings of eclipses made between 2000 and 2010 are presented for two binary systems with hot subdwarf primary stars. In the case of AA Dor, an sdOB star with a very cool secondary, the period is found to be constant ...

    • Clustering of HI galaxies in the HI parkes all sky survey and arecibo legacy fast alfa survey 

      Passmoor, S. S.; Cress, Catherine; Faltenbacher, A (Oxford University Press, 2011)
      We investigate the clustering of H I-selected galaxies in the Arecibo Legacy Fast ALFA Survey (ALFALFA) and compare results with those obtained for the H I Parkes All Sky Survey (HIPASS). Measurements of the angular ...

    • Disentangling non-gaussianity, bias, and general relativistic effects in the galaxy distribution 

      Bruni, Marco; Crittenden, Robert; Maartens, Roy (American Physical Society, 2012)
      Local non-Gaussianity, parametrized by f NL , introduces a scale-dependent bias that is strongest at large scales, precisely where general relativistic (GR) effects also become significant. With future data, it should ...

    • Reconstruction of dark energy and expansion dynamics using Gaussian processes 

      Seikel, Marina; Clarkson, Chris (IOP Publishing, 2012)
      An important issue in cosmology is reconstructing the effective dark energy equation of state directly from observations. With few physically motivated models, future dark energy studies cannot only be based on constraining ...

    • The complex physics of dusty star-forming galaxies at high redshifts as revealed by Herschel and Spitzer 

      Lo Faro, Barbara; Franceschini, Alberto; Vaccari, M.; Silva, L.; Rodighiero, G.; Berta, S.; Bock, J.; Burgarella, D.; Buat, V.; Cava, A.; Clements, D.L.; Cooray, Asantha; Farrah, D.; Feltre, Anna; Gonzalez-Solares, Eduardo A.; Hurley, P.; Lutz, D.; Magdis, G.; Magnelli, B.; Marchetti, L.; Oliver, S.J.; Page, Matthew J.; Popesso, P.; Pozzi, F.; Rigopoulou, D.; Rowan-Robinson, M.; Roseboom, I.G.; Scott, Douglas; Smith, A.J.; Symeonidis, Myrto; Wang, L.; Wuyts, S. (IOP Publishing, 2013)
      We combine far-infrared photometry from Herschel (PEP/HerMES) with deep mid-infrared spectroscopy from Spitzer to investigate the nature and the mass assembly history of a sample of 31 luminous and ultraluminous infrared ...

    • Comparative study: the effect of annealing conditions on the properties of P3HT:PCBM blends 

      Motaung, David E.; Malgas, Gerald; Nkosi, Steven S.; Mhlongo, Gugu H.; Mwakikunga, Bonex W.; Malwela, Thomas; Arendse, Christopher; Muller, Theophillus F. G.; Cummings, Franscious R. (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 ...

    • Mining the Herschel-Astrophysical Terahertz Large Area Survey: submillimetre-selected blazars in equatorial fields 

      Lopez-Caniego, M.; Gonzalez-Nuevo, J.; Massardi, M.; Jarvis, Matt (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) ...

    • Self-catalytic growth of tin oxide nanowires by chemical vapor deposition process 

      Thabethe, Bongani; Malgas, Gerald; Motaung, David; Malwela, Thomas; Arendse, Christopher (Hindawi, 2013)
      We report on the synthesis of tin oxide (SnO2) nanowires by a chemical vapor deposition (CVD) process. Commercially bought SnO nanopowders were vaporized at 1050∘C for 30 minutes with argon gas continuously passing through ...

    • Herschel-ATLAS/GAMA: What determines the far-infrared properties of radio galaxies? 

      Virdee, J.S.; Hardcastle, M.J.; Jarvis, Matt (OUP, 2013)
      We perform a stacking analysis of Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) data in order to obtain isothermal dust temperatures and rest-frame luminosities at 250 µm (L250), for a well-defined sample ...

    • Herschel-atlas/Gama: a difference between star formation rates in strong-line and weak-line radio galaxies 

      Hardcastle, M.J.; Ching, J.H.Y.; Jarvis, Matt (OUP, 2013)
      We have constructed a sample of radio-loud objects with optical spectroscopy from the Galaxy and Mass Assembly (GAMA) project over the Herschel Astrophysical Terahertz Large Area Survey (Herschel-ATLAS) Phase 1 fields. ...

    • Existence domains of dust-acoustic solitons and supersolitons 

      Maharaj, S.K.; Bharuthram, Ramashwar; Singh, S. V.; Lakhina, G. S. (AIP PublishingAIP Publishing, 2013)
      Using the Sagdeev potential method, the existence of large amplitude dust-acoustic solitons and supersolitons is investigated in a plasma comprising cold negative dust, adiabatic positive dust, Boltzmann electrons, and ...

    • An overview of the Dwarf Galaxy Survey 

      Remy-Ruyer, A.; Galametz, M.; Vaccari, Mattia; Madden, S.C. (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 ...

    • Galaxy and mass assembly: evolution of the Hα luminosity function and star formation rate density up to z < 0.35 

      Gunawardhana, M.L.P.; Hopkins, A.M.; Bland–Hawthorn, J.; Prescott, M. (OUP, 2013)
      Measurements of the low-z Hα luminosity function, Φ, have a large dispersion in the local number density of sources (∼0.5–1 Mpc−3 dex−1), and correspondingly in the star formation rate density (SFRD). The possible causes ...

    • Gama/H-Atlas: The dust opacity-stellar mass surface density relation for spiral galaxies 

      Grootes, M.W.; Tuffs, R.J.; Jarvis, Matt (IOP Science, 2013)
      We report the discovery of a well-defined correlation between B-band face-on central optical depth due to dust and the stellar mass surface density of nearby spiral galaxies. This relation was derived from a sample of ...

    • H-Atlas: The cosmic abundance of dust from the far-infrared background power spectrum 

      Thacker, Cameron; Cooray, Asantha; Jarvis, Matt (IOP Science, 2013)
      We present a measurement of the angular power spectrum of the cosmic far-infrared background (CFIRB) anisotropies in one of the extragalactic fields of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) at ...

    • Comparison of Hi and optical redshifts of galaxies - The impact of redshift uncertainties on spectral line stacking 

      Maddox, Natasha; Hess, Kelley M.; Blyth, S.-L.; Jarvis, Matt (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 ...