Probing Cosmology beyond ΛCDM using the SKA
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Date
2023
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Indian Academy of Sciences
Abstract
The cosmological principle states that the Universe is statistically homogeneous and isotropic at
large distance scales. Currently, there exist many observations which indicate a departure from this principle.
It has been shown that many of these observations can be explained by invoking superhorizon cosmological
perturbations and may be consistent with the Big Bang paradigm. Remarkably, these modes simultaneously
explain the observed Hubble tension, i.e., the discrepancy between the direct and indirect measurements of
the Hubble parameter. We propose several tests of the cosmological principle using SKA. In particular, we
can reliably extract the signal of dipole anisotropy in the distribution of radio galaxies. The superhorizon
perturbations also predict a significant redshift dependence of the dipole signal, which can be well tested by
the study of signals of reionization and the dark ages using SKA. We also propose to study the alignment of
radio galaxy axes as well as their integrated polarization vectors over distance scales ranging from a few Mpc
to Gpc. We discuss data analysis techniques that can reliably extract these signals from data.
Description
Keywords
Cosmology, Astronomy, Physics, Galaxies
Citation
Ghosh, S. et al. (2023). Probing cosmology beyond ΛCDM using the SKA. 44, 22. https://doi.org/10.1007/s12036-023-09918-y