Browsing Faculty of Natural Sciences by Title

Now showing items 456-475 of 2571

    • 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 ...

    • Cosmic evolution of star-forming galaxies to z 1.8 in the faint low-frequency radio source population 

      Ocran, E. F.; Taylor, A. R.; Vaccari, M. (Oxford University Press, 2019)
      We study the properties of star-forming galaxies selected at 610 MHz with the GMRT in a survey covering ∼1.86 deg2 down to a noise of ∼7.1 μJy beam−1. These were identified by combining multiple classification diagnostics: ...

    • 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) ...

    • Cosmic microwave background constraints on a physical model of reionization 

      Paul, S; Choudhury, T.R; Mukherjee, S (Oxford University Press, 2021)
      We study constraints on allowed reionization histories by comparing predictions of a physical seminumerical model with secondary temperature and polarization anisotropies of the cosmic microwave background (CMB). Our model ...

    • Cosmic sands: the origin of dusty, star-forming galaxies in the epoch of reionization 

      Davé, Romeel; Lower, Sidney; Narayanan, Desika (The astrophysical journal, 2023)
      We present the Cosmic Sands suite of cosmological zoom-in simulations based on the simba galaxy formation model in order to study the buildup of the first massive and dusty galaxies in the early universe. Residing in the ...

    • Cosmological 3D Hi Gas Map with HETDEX Lyα Emitters and eBOSS QSOs at z = 2: IGM-Galaxy/QSO Connection and a ∼ 40-Mpc Scale Giant Hii Bubble Candidate 

      Jarvis, Matt J.; Mukae, Shiro; Ouchi, Masami (IOP Publishing, 2020)
      We present cosmological (30−400 Mpc) distributions of neutral hydrogen (H i) in the intergalactic medium (IGM) traced by Lyα emitters (LAEs) and QSOs at z = 2.1–2.5, selected with the data of the ongoing Hobby–Eberly ...

    • Cosmological baryon transfer in the SIMBA simulations 

      Dave, Romeel; Borrow, Josh; Angles-Alcazar, Daniel (Oxford University Press, 2019)
      We present a framework for characterizing the large-scale movement of baryons relative to dark matter in cosmological simulations, requiring only the initial conditions and final state of the simulation. This is performed ...

    • Cosmological constraints from the power spectrum and bispectrum of 21cm intensity maps 

      Karagiannis, Dionysios; Maartens, Roy; Randrianjanahary, Liantsoa F. (IOP Publishing, 2022)
      The 21cm emission of neutral hydrogen is a potential probe of the matter distribution in the Universe after reionisation. Cosmological surveys of this line intensity will be conducted in the coming years by the SKAO and ...

    • Cosmological constraints on post-Newtonian parameters in effectively massless scalar-tensor theories of gravity 

      Rossi, Massimo; Ballardini, Mario; Braglia, Matteo (2019)
      We study the cosmological constraints on the variation of Newton’s constant and on post-Newtonian parameters for simple models of the scalar-tensor theory of gravity beyond the extended Jordan-BransDicke theory. We restrict ...

    • Cosmology from HI galaxy surveys with the SKA 

      Maartens, Roy; Abdalla, Filipe B.; Bull, Philip; Camera, Stefano; Benoit-Levy, Aurelien; Joachimi, Benjamin; Kirk, Donnacha; Klöckner, Hans-Rainer; Raccanelli, Alvise; Santos, Mario G.; Zhao, Gong-Bo (Proceedings of Science, 2014)
      The Square Kilometer Array (SKA) has the potential to produce galaxy redshift surveys which will be competitive with other state of the art cosmological experiments in the next decade. In this chapter we summarise what ...

    • Cosmology on the largest scales with the SKA 

      Camera, Stefano; Raccanelli, Alvise; Bull, Philip; Bertacca, Daniele; Chen, Xuelei; Ferreira, Pedro G.; Kunz, Martin; Maartens, Roy; Mao, Yi; Santos, Mario G.; Shapiro, Paul R.; Viel, Matteo; Xug, Yidong (Proceedings of Science, 2014)
      The study of the Universe on ultra-large scales is one of the major science cases for the Square Kilometre Array (SKA). The SKA will be able to probe a vast volume of the cosmos, thus representing a unique instrument, ...

    • Cosmology on ultralarge scales with intensity mapping of the neutral hydrogen 21 cm emission: limits on primodial non-gaussianity 

      Camera, Stefano; Santos, Mario G.; Ferreira, Pedro G.; Ferramacho, Luis (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 − ...

    • Cosmology with a SKA HI intensity mapping survey 

      Santos, Mario G.; Bull, Philip; Alonso, David; Camera, Stefano; Ferreira, Pedro G.; Bernardi, Gianni; Maartens, Roy; Viel, Matteo; Villaescusa-Navarro, Francisco; Abdalla, Filipe B.; Jarvis, Matt; Metcalf, R. Benton; Pourtsidou, A.; Wolz, Laura (Proceedings of Science, 2014)
      HI intensity mapping (IM) is a novel technique capable of mapping the large-scale structure of the Universe in three dimensions and delivering exquisite constraints on cosmology, by using HI as a biased tracer of the ...

    • Cosmology with Phase 1 of the Square Kilometre Array Red Book 2018: Technical specifications and performance forecasts 

      Bacon, David J; Battye, Richard A.; Bull, Philip (Cambridge University Press, 2020)
      We present a detailed overview of the cosmological surveys that we aim to carry out with Phase 1 of the Square Kilometre Array (SKA1) and the science that they will enable. We highlight three main surveys: a medium-deep ...

    • Cosmology with photometrically classified type IA supernovae from the SDSS-II supernova survey 

      Campbell, Heather; D’Andrea, Chris B.; Nichol, Robert C.; Sako, Masao; Smith, Mathew (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 ...

    • COSMOS2020: A panchromatic view of the universe to z ∼ 10 from two complementary catalogs 

      Weaver, J.R; Vaccari, M.; Kauffmann, O.B. (University of the Western Cape, 2022)
      The Cosmic Evolution Survey (COSMOS) has become a cornerstone of extragalactic astronomy. Since the last public catalog in 2015, a wealth of new imaging and spectroscopic data have been collected in the COSMOS field. This ...

    • Cosmos2020: A panchromatic view of the universe to z∼10 from two complementary catalogs 

      Weaver, John R.; Kauffmann, Olivier; Vaccari, Mattia (IOP Publishing, 2022)
      The Cosmic Evolution Survey (COSMOS) has become a cornerstone of extragalactic astronomy. Since the last public catalog in 2015, a wealth of new imaging and spectroscopic data have been collected in the COSMOS field. This ...

    • Cost of Traditional Herbal Medicines for Noncommunicable Diseases in Rural and Urban Communities in South Africa 

      Gail Denise, Hughes; Oluwaseyi Mayode, Aboyade (Elsevier Inc., 2022)
      Objectives: This study assessed traditional herbal medicine (THM) and conventional medicine (CM) utilization among par- participants with a noncommunicable diseases in South Africa. Methods: A cross-sectional study of the ...

    • Coulomb excitation of 102 Ru with 12 C and 16 O 

      Garrett, Paul Edward; Zielińska, M.; Bergmaier, Andreas (American Physical Society, 2022)
      The Coulomb excitation of 102Ru was performed with beams of 12C and 16O ions. The beam particles scattered at forward angles were momentum analyzed with a magnetic spectrograph. The resolution achieved enabled the ...

    • Coulomb excitation of and a change in structure approaching N = Z = 40 

      Gillespie, S; Henderson, J; Abrahams, K; Ali, F (American Physical Society, 2021)
      Background: Nuclei approaching are known to exhibit strongly deformed structures and are thought to be candidates for shape coexistence. In the krypton isotopes, are poorly characterized, preventing an understanding of ...