Browsing Research Articles (Physics) by Title

Now showing items 1-20 of 56

  • Annealing effect of hybrid solar cells based on poly (3-hexylthiophene) and zinc-oxide nanostructures 

    Motaung, David; Malgas, Gerald; Ray, Suprakas S.; Arendse, Christopher (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/ ...

  • Black hole - galaxy correlations without self-regulation 

    Angles-Alcazar, Daniel; Ozel, Feryal; Dave, Romeel (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 ...

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

    Lo Faro, B.; Franceschini, A.; Vaccari, M.; Silva, L.; Rodighiero, G.; Berta, S.; Bock, J.; Burgarella, D.; Buat, V.; Cava, A.; Clements, D.L.; Cooray, Asantha; Farrah, D.; Feltre, A.; Gonzalez-Solares, Eduardo A.; Hurley, P.; Lutz, D.; Magdis, G.; Magnelli, B.; Marchetti, L.; Oliver, S. J.; Page, M. J.; Popesso, P.; Pozzi, F.; Rigopoulou, D.; Rowan-Robinson, M.; Roseboom, I. G.; Scott, Douglas; Smith, A. J.; Symeonidis, M.; 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 ...

  • The COS-Halos survey: Rationale, design and a census of circumgalactic neutral hydrogen 

    Tumlinson, Jason; Thom, Christopher; Dave, Romeel; Werk, Jessica K.; Prochaska, J. Xavier; Tripp, Todd M.; Katz, Neal; Oppenheimer, Benjamin D.; Meiring, Joseph D.; Ford, Amanda Brady; O'Meara, John M.; Peeples, Molly S.; Sembach, Kenneth R.; Weinberg, David H. (IOP Publishing, 2013)
    We present the design and methods of the COS-Halos survey, a systematic investigation of the gaseous halos of 44 z = 0.15–0.35 galaxies using background QSOs observed with the Cosmic Origins Spectrograph aboard the Hubble ...

  • The cosmic evolution of the IMF under the Jeans conjecture with implications for massive galaxies 

    Narayanan, Desika; Dave, Romeel (Oxford University Press, 2013)
    We examine the cosmic evolution of a stellar initial mass function (IMF) in galaxies that varies with the Jeans mass in the interstellar medium, paying particular attention to the K-band stellar mass-to-light ratio (M/LK) ...

  • A deep search for faint galaxies associated with very low-redshift C iv absorbers: A case with cold-accretion characteristics 

    Burchett, Joseph N.; Tripp, Todd M.; Werk, Jessica K.; Howk, J. Christopher; Dave, Romeel; Prochaska, J. Xavier; Ford, Amanda Brady (The American Astronomical Society, 2013)
    Studies of QSO absorber–galaxy connections are often hindered by inadequate information on whether faint/dwarf galaxies are located near the QSO sight lines. To investigate the contribution of faint galaxies to QSO ...

  • The Edinburgh-Cape Blue Object Survey - III. Zone 2; galactic latitudes -30? > b > -40? 

    Kilkenny, David; Koen, Chris; Hambly, N.; MacGillivray, H.; Stobie, R. S.; O’Donoghue, D. (Oxford University Press, 2013)
    The Edinburgh–Cape Blue Object Survey seeks to identify point sources with an ultraviolet excess. Results for zone 2 of the survey are presented here, covering that part of the South Galactic Cap between 30◦ and 40◦ from ...

  • Einstein's legacy in galaxy surveys 

    Camera, Stefano; Maartens, Roy; Santos, Mario G. (Oxford University Press, 2015)
    Non-Gaussianity in the primordial fluctuations that seeded structure formation produces a signal in the galaxy power spectrum on very large scales. This signal contains vital information about the primordial Universe, but ...

  • Evolution from 4f-electron antiferromagnetic to ferromagnetic order in the CeCu(Ge1-xSnx) alloy series (0≤x≤1) 

    Altayeb, Anas; Sondezi, B. M.; Tchoula Tchokonte, Moise; Strydom, A. M.; Doyle, T. B.; Kaczorowski, D. (American Institute of Physics Inc., 2017)
    We report the evolution from ferromagnetic (FM) to antiferromagnetic (AFM) state in CeCu(Ge1-xSnx) investigated by means of magnetic and heat capacity measurements. X-ray diffraction studies for all compositions indicate ...

  • 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 ...

  • The faint radio source population at 15.7 GHz - II. Multi-wavelength properties 

    Whittam, I.H.; Riley, J.M.; Green, D.A.; Jarvis, Matt; Vaccari, M. (Oxford University Press, 2015)
    A complete, flux density limited sample of 96 faint (> 0:5 mJy) radio sources is selected from the 10C survey at 15.7 GHz in the Lockman Hole. We have matched this sample to a range of multi-wavelength catalogues, including ...

  • The faint source population at 15.7 GHz - I. The radio properties 

    Whittam, I.; Riley, J.; Jarvis, Matt; Green, D.A.; Prandoni, I.; Guglielmino, G.; Morganti, R.; Röttgering, H. J. A.; Garrett, M. A. (Oxford University Press, 2013)
    We have studied a sample of 296 faint (>0.5 mJy) radio sources selected from an area of the Tenth Cambridge (10C) survey at 15.7 GHz in the Lockman Hole. By matching this catalogue to several lower frequency surveys (e.g. ...

  • A framework for assessing the performance of pulsar search pipelines 

    van Heerden, E.; Karastergiou, A.; Roberts, J. (Oxford Unviersity Press, 2016)
    In this paper, we present a framework for assessing the effect of non-stationary Gaussian noise and radio frequency interference (RFI) on the signal to noise ratio, the number of false positives detected per true positive ...

  • Gaia Data Release 1. Open cluster astrometry: performance, limitations, and future prospects 

    van Leeuwen, F.; Vallenari, A.; Vaccari, M. (EDP Sciences, 2017)
    CONTEXT: The first Gaia Data Release contains the Tycho-Gaia Astrometric Solution (TGAS). This is a subset of about 2 million stars for which, besides the position and photometry, the proper motion and parallax are ...

  • 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. ...

  • 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 ...

  • The high-ion content and kinematics of low-redshift lyman limit systems 

    Fox, Andrew J.; Lehner, Nicholas; Dave, Romeel; Tumlinson, Jason; Howk, J. Christopher; Tripp, Todd M.; Prochaska, J. Xavier; O'Meara, John M.; Werk, Jessica K.; Bordoloi, Rongmon; Katz, Neal; Oppenheimer, Benjamin D. (The American Astronomical Society, 2013)
    We study the high-ion content and kinematics of the circumgalactic medium around low-redshift galaxies using a sample of 23 Lyman limit systems (LLSs) at 0.08 < z < 0.93 observed with the Cosmic Origins Spectrograph on ...

  • High-Precision Branching Ratio Measurement for the Superallowed + Emitter 74Rb 

    Dunlop, R.; Ball, G.C.; Leslie, J.R.; Svensson, C.E.; Towner, I.S.; Andreoiu, C.; Chagnon-Lessard, S.; Chester, A.; Cross, D.S.; Finlay, P.; Garnsworthy, A.B.; Garrett, P.E.; Glister, J.; Hackman, G.; Hadinia, B.; Leach, K. G.; Rand, E.T.; Starosta, K.; Tardiff, E.R.; Triambak, S.; Williams, S. J.; Wong, J.; Yates, S.W.; Zganjar, E.F. (American Physical Society, 2013)
    A high-precision branching-ratio measurement for the superallowed β + decay of 74Rb was performed at the TRIUMF Isotope Separator and Accelerator (ISAC) radioactive ion-beam facility. The scintillating electronpositron tagging ...

  • The host haloes of O I absorbers in the reionization epoch 

    Finlator, Kristian; Muñoz, Joseph A.; Dave, Romeel; Oppenheimer, B. D.; Peng Oh, S.; Özel, Feryal (Oxford University Press, 2013)
    We use a radiation hydrodynamic simulation of the hydrogen reionization epoch to study OI absorbers at z ∼ 6. The intergalactic medium (IGM) is reionized before it is enriched; hence, OI absorption originates within dark ...

  • Hot subdwarf stars in close-up view IV. Helium abundances and the 3He isotopic anomaly of subdwarf B stars 

    Geier, S.; Edelmann, H.; Kilkenny, David; O'Donoghue, D.; Marsh, T.R.; Copperwheat, C. (EDP Sciences, 2013)
    Atmospheric parameters and helium abundances of 44 bright subdwarf B stars have been determined. More than half of our sample consists of newly discovered stars from the Edinburgh Cape survey. We showed that effective ...