Browsing by Author "Skordis, C."

Now showing items 1-15 of 15

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      Ambiguous tests of general relativity on cosmological scales 

      Zuntz, J.; Baker, T.; Ferreira, P. G.; Skordis, C. (2012)
      There are a number of approaches to testing General Relativity (GR) on linear scales using parameterized frameworks for modifying cosmological perturbation theory. It is sometimes assumed that the details of any given ...
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      CONSTRAINING the PROPERTIES of DARK MATTER with OBSERVATIONS of the COSMIC MICROWAVE BACKGROUND 

      Thomas, D. B.; Kopp, M.; Skordis, C. (2016)
      We examine how the properties of dark matter, parameterized by an equation-of-state parameter w and two perturbative generalized dark matter (GDM) parameters, c 2 s (the sound speed) and (the viscosity), are constrained ...
    • Article  

      Cosmological constraints on Brans-Dicke theory 

      Avilez, A.; Skordis, C. (2014)
      We report strong cosmological constraints on the Brans-Dicke (BD) theory of gravity using cosmic microwave background data from Planck. We consider two types of models. First, the initial condition of the scalar field is ...
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      Cosmology and fundamental physics with the Euclid satellite 

      Amendola, L.; Appleby, S.; Bacon, D.; Baker, T.; Baldi, M.; Bartolo, N.; Blanchard, A.; Bonvin, C.; Borgani, S.; Branchini, E.; Burrage, C.; Camera, S.; Carbone, C.; Casarini, L.; Cropper, M.; de Rham, C.; Di Porto, C.; Ealet, A.; Ferreira, P. G.; Finelli, F.; García-Bellido, J.; Giannantonio, T.; Guzzo, L.; Heavens, A.; Heisenberg, L.; Heymans, C.; Hoekstra, H.; Hollenstein, L.; Holmes, R.; Horst, O.; Jahnke, K.; Kitching, T. D.; Koivisto, T.; Kunz, M.; La Vacca, G.; March, M.; Majerotto, E.; Markovic, K.; Marsh, D.; Marulli, F.; Massey, R.; Mellier, Y.; Mota, D. F.; Nunes, N. J.; Percival, W.; Pettorino, V.; Porciani, C.; Quercellini, C.; Read, J.; Rinaldi, M.; Sapone, D.; Scaramella, R.; Skordis, C.; Simpson, F.; Taylor, A.; Thomas, S.; Trotta, R.; Verde, L.; Vernizzi, F.; Vollmer, A.; Wang, Y.; Weller, J.; Zlosnik, T. (2013)
      Euclid is a European Space Agency medium-class mission selected for launch in 2019 within the Cosmic Vision 2015 - 2025 program. The main goal of Euclid is to understand the origin of the accelerated expansion of the ...
    • Article  

      Cosmology of the Galileon extension of Bekenstein's theory of relativistic modified Newtonian dynamics 

      Złośnik, T. G.; Skordis, C. (2017)
      A generalization of Bekenstein's Tensor-Vector-Scalar (TeVeS) model of modified gravity has recently been proposed as an alternative to dark matter. This model - which we will refer to as g-TeVeS - utilizes a Galileon-induced ...
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      The dark energy cosmic clock: A new way to parametrise the equation of state 

      Tarrant, E. R. M.; Copeland, E. J.; Padilla, A.; Skordis, C. (2013)
      We propose a new parametrisation of the dark energy equation of state, which uses the dark energy density, Ωe as a cosmic clock. We expand the equation of state in a series of orthogonal polynomials, with Ωe as the expansion ...
    • Article  

      Extensive investigation of the generalized dark matter model 

      Kopp, M.; Skordis, C.; Thomas, D. B. (2016)
      The cold dark matter (CDM) model, wherein the dark matter is treated as a pressureless perfect fluid, provides a good fit to galactic and cosmological data. With the advent of precision cosmology, it should be asked whether ...
    • Article  

      A fast route to modified gravitational growth 

      Baker, T.; Ferreira, P.; Skordis, C. (2014)
      The growth rate of the large-scale structure of the Universe has been advocated as the observable par excellence for testing gravity on cosmological scales. By considering linear-order deviations from general relativity, ...
    • Article  

      Linking tests of gravity on all scales: From the strong-field regime to cosmology 

      Baker, T.; Psaltis, D.; Skordis, C. (2015)
      The current effort to test general relativity (GR) employs multiple disparate formalisms for different observables, obscuring the relations between laboratory, astrophysical, and cosmological constraints. To remedy this ...
    • Article  

      Models of dark matter coupled to dark energy 

      Pourtsidou, A.; Skordis, C.; Copeland, E. J. (2013)
      We present three distinct types of models of dark energy in the form of a scalar field which is explicitly coupled to dark matter. Our construction draws from the pull-back formalism for fluids and generalizes the fluid ...
    • Article  

      Modified gravity and cosmology 

      Clifton, T.; Ferreira, P. G.; Padilla, A.; Skordis, C. (2012)
      In this review we present a thoroughly comprehensive survey of recent work on modified theories of gravity and their cosmological consequences. Amongst other things, we cover General Relativity, scalar-tensor, Einstein-æther, ...
    • Article  

      The parameterized post-Friedmann framework for theories of modified gravity: Concepts, formalism, and examples 

      Baker, T.; Ferreira, P. G.; Skordis, C. (2013)
      A unified framework for theories of modified gravity will be an essential tool for interpreting the forthcoming deluge of cosmological data. We present such a formalism, the parameterized post-Friedmann framework (PPF), ...
    • Article  

      Parametrized post-Friedmannian framework for interacting dark energy theories 

      Skordis, C.; Pourtsidou, A.; Copeland, E. J. (2015)
      We present the most general parametrization of models of dark energy in the form of a scalar field which is explicitly coupled to dark matter. We follow and extend the parametrized post-Friedmannian approach, previously ...
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      The Parametrized Post-Newtonian-Vainshteinian formalism 

      Avilez-Lopez, A.; Padilla, A.; Saffin, P. M.; Skordis, C. (2015)
      Light degrees of freedom that modify gravity on cosmological scales must be ''screened on solar system scales in order to be compatible with data. The Vainshtein mechanism achieves this through a breakdown of classical ...
    • Article  

      Testing general relativity with cosmology: a synopsis of the parametrized post-Friedmann approach 

      Ferreira, P. G.; Baker, T.; Skordis, C. (2014)
      More than half a century after the Chapel Hill meeting of 1957, the landscape of general relativity has been transformed. In relativistic cosmology we are entering an era in which we can seriously consider testing some of ...