Browsing Research Articles (Physics) by Issue Date

Now showing items 41-60 of 510

    • Forming the Moon from terrestrial silicate-rich material 

      de Meijer, R.J.; Anisichkin, V.F.; van Westrenen, W. (Elsevier, 2013)
      Recent high-precision measurements of the isotopic composition of lunar rocks demonstrate that the bulk silicate Earth and the Moon show an unexpectedly high degree of similarity. This is inconsistent with one of the ...

    • Isothermal dust models of Herschel-ATLAS galaxies 

      Smith, Daniel J.B.; Hardcastle, M.J.; Jarvis, Matt (Oxford University Press, 2013)
      We use galaxies from the Herschel-ATLAS survey, and a suite of ancillary simulations based on an isothermal dust model, to study our ability to determine the effective dust temperature, luminosity and emissivity index of ...

    • 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 ...

    • 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 ...

    • 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 ...

    • 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) ...

    • The slow flow model of dust eflux in local star-forming galaxies 

      Zahid, H.; Torrey, Paul; Dave, Romeel; Geller, Margaret; Kudritzki, Rolf; Kewley, Lisa J. (Oxford University Press, 2013)
      We develop a dust efflux model of radiation pressure acting on dust grains which successfully reproduces the relation between stellar mass, dust opacity and star forma- tion rate observed in local star-forming galaxies. ...

    • 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 ...

    • Testing gravity using large-scale redshift-space distortions 

      Raccanelli, Alvise; Bertacca, Daniele; Pietrobon, Davide; Schmidt, Fabian; Samushia, Lado; Bartolo, Nicola; Doré, Olivier; Matarrese, Sabino; Percival, Will J. (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. ...

    • Radio-loud active calactic nucleus: is there a link between luminosity and cluster environment? 

      Ineson, J.; Croston, J. H.; Jarvis, Matt; Hardcastle, M.J.; Evans, D. A.; Kraft, R. P. (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 ...

    • Sample variance, source clustering and their influence on the counts of faint radio sources 

      Heywood, Ian; Jarvis, Matt; Condon, James J. (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 ...

    • Testing homegeneity with Galaxy Star formation histories 

      Hoyle, Ben; Jimenez, Raul; Maartens, Roy; Heavens, Alan; Clarkson, Chris; Tojeiro, Rita (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 ...

    • Students' ontological security and agency in science education - an example from reasoning about the use of gene technology 

      Lindahl, Mats Gunnar; Linder, Cedric (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 ...

    • The ongoing pursuit of R Coronae Borealis stars: the ASAS-3 survey strikes again 

      Tisserand, P.; Clayton, G.; Kilkenny, David; Welch, D. L.; Wyrzykowsk, L.; Pilecki, B. (EDP Sciences, 2013)
      CONTEXT: R Coronae Borealis stars( RCBs) are rare, hydrogen-deficient, carbon rich super giant variable stars that are likely the evolved merger products of pairs of CO and He white dwarfs. Only 55 RCB stars have been found ...

    • Properties of Type Ia supernovae inside rich galaxy clusters 

      Xavier, Henrique S.; Gupta, Ravi R.; Smith, Mathew; Sako, Masao; D’Andrea, Chris B.; Frieman, Joshua A.; Galbany, Lluis; Garnavich, Peter M.; Marriner, John; Nichol, Robert C.; Olmstead, Matthew D.; Schneider, Donald P. (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 ...

    • Matter bispectrum in cubic Galileon cosmologies 

      Bartolo, Nicola; Bellini, Emilio; Bertacca, Daniele; Matarrese, Sabino (IOP Science, 2013)
      In this paper we obtain the bispectrum of dark matter density perturbations in the frame of covariant cubic Galileon theories. This result is obtained by means of a semi- analytic approach to second-order perturbations ...

    • Physical properties of spectroscopically-confirmed galaxies at z >= 6. II. Morphology of the rest-frame UV continuum and Lyman-alpha emission 

      Jiang, Linhua; Egami, Eiichi; Fan, Xiaohui; Dave, Romeel (IOP Science, 2013)
      We present a detailed structural and morphological study of a large sample of spectroscopicallyconfirmed galaxies at z ≥ 6, using deep HST near-IR broad-band images and Subaru optical narrowband images. The galaxy sample ...

    • VLT/XSHOOTER & Subaru/MOIRCS spectroscopy of HUDF-YD3: No evidence for Lyman-alpha emission at z=8.55 

      Bunker, Andrew J.; Caruana, Joseph; Wilkins, Stephen M.; Jarvis, Matt (Oxford University Press, 2013)
      We present spectroscopic observations with VLT/XSHOOTER and Subaru/MOIRCS of a relatively bright Y -band drop-out galaxy in the Hubble Ultra Deep Field, first selected by Bunker et al. (2010), McLure et al. (2010) and ...

    • Theoretical evolution of optical strong lines across cosmic time 

      Kewley, Lisa J.; Dopita, Michael A.; Dave, Romeel; Leitherer, Claus; Yuan, Tiantian; Allen, Mark; Groves, Brent; Sutherland, Ralph (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 ...