Measuring redshift-space distortions with future SKA surveys

Alvise Raccanelli, Philip Bull, Stefano Camera, David Bacon, Chris Blake, Olivier Doré, Pedro Ferreira, Roy Maartens, Mario Santos, Matteo Viel, Gong Bo Zhao

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The peculiar motion of galaxies can be a particularly sensitive probe of gravitational collapse. As such, it can be used to measure the dynamics of dark matter and dark energy as well the nature of the gravitational laws at play on cosmological scales. Peculiar motions manifest themselves as an overall anisotropy in the measured clustering signal as a function of the angle to the line-ofsight, known as redshift-space distortion (RSD). Limiting factors in this measurement include our ability to model non-linear galaxy motions on small scales and the complexities of galaxy bias. The anisotropy in the measured clustering pattern in redshift-space is also driven by the unknown distance factors at the redshift in question, the Alcock-Paczynski distortion. This weakens growth rate measurements, but permits an extra geometric probe of the Hubble expansion rate. In this short chapter we will briefly describe the scientific background to the RSD technique, and forecast the potential of the SKA phase 1 and the SKA2 to measure the growth rate using both galaxy catalogues and intensity mapping, assessing their competitiveness with current and future optical galaxy surveys.

Original languageEnglish
Article number031
JournalProceedings of Science
Publication statusPublished - 30 Jun 2014
EventAdvancing Astrophysics with the Square Kilometre Array - Giardini Naxos, Italy
Duration: 9 Jun 201413 Jun 2014


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