Browsing by Author "Maartens, Roy"

Now showing items 21-30 of 30

    • Nonlinear modulation of the HI power spectrum on ultra-large scales. I 

      Umeh, Obinna; Maartens, Roy; Santos, Mario G. (IOP Science, 2015)
      Intensity mapping of the neutral hydrogen brightness temperature promises to provide a three-dimensional view of the universe on very large scales. Nonlinear effects are typically thought to alter only the small-scale ...

    • Null tests of the concordance model in the era of Euclid and the SKA 

      Bengaly, Carlos; Clarkson, Chris; Kunz, Martin; Maartens, Roy (Elsevier, 2021)
      We perform null tests of the concordance model, using H (z) measurements that mimic next-generation surveys such as Euclid and the SKA. To this end, we deploy a non-parametric method, so that we make minimal assumptions ...

    • Null tests of the cosmological constant using supernovae 

      Yahya, Sahba; Seikel, Marina; Clarkson, Chris; Maartens, Roy; Smith, Mathew (American Physical Society, 2014)
      The standard concordance model of the Universe is based on the cosmological constant as the driver of accelerating expansion. This concordance model is being subjected to a growing range of inter-locking observations. ...

    • The observed galaxy bispectrum from single-field inflation in the squeezed limit 

      Koyama, Kazuya; Umeh, Obinna; Maartens, Roy; Bertacca, Daniele (IOP Publishing, 2018)
      Using the consistency relation in Fourier space, we derive the observed galaxy bispectrum from single- eld in ation in the squeezed limit, in which one of the three modes has a wavelength much longer than the other two. ...

    • Overview of Cosmology with the SKA 

      Maartens, Roy; Abdalla, Filipe B.; Jarvis, Matt; Santos, Mario G. (Proceedings of Science, 2014)
      The new frontier of cosmology will be led by three-dimensional surveys of the large-scale structure of the Universe. Based on its all-sky surveys and redshift depth, the SKA is destined to revolutionize cosmology, in ...

    • Probing the imprint of interacting dark energy on very large scales 

      Duniya, Didam, G. A.; Bertacca, Daniele; Maartens, Roy (American Physical Society, 2015)
      The observed galaxy power spectrum acquires relativistic corrections from light-cone effects, and these corrections grow on very large scales. Future galaxy surveys in optical, infrared and radio bands will probe increasingly ...

    • Synergies between intensity maps of hydrogen lines 

      Fonseca, Jose; Maartens, Roy; Santos, Mario G. (Oxford University Press, 2018)
      We study synergies between Hi 21cm and Hα intensity map observations, focusing on SKA1- like and SPHEREx-like surveys. We forecast how well such a combination can measure features in the angular power spectrum on the ...

    • Testing foundations of modern cosmology with SKA all-sky surveys 

      Schwarz, Dominik J.; Bacon, David; Chen, Song; Clarkson, Chris; Huterer, Dragan; Kunz, Martin; Maartens, Roy; Raccanelli, Alvise; Rubart, Matthias; Starck, Jean-Luc (Proceedings of Science, 2014)
      Continuum and HI surveys with the Square Kilometre Array (SKA) will allow us to probe some of the most fundamental assumptions of modern cosmology, including the Cosmological Principle. SKA all-sky surveys will map an ...

    • 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 ...

    • Wide-angle effects in multi-tracer power spectra with Doppler corrections 

      Paul, Pritha; Clarkson, Chris; Maartens, Roy (IOP Publishing, 2023)
      . We examine the computation of wide-angle corrections to the galaxy power spectrum including redshift-space distortions and relativistic Doppler corrections, and also including multiple tracers with differing clustering, ...