Constraining the growth rate of structure with phase correlations
Abstract
We show that correlations between the phases of the galaxy density field in redshift space provide additional information about the growth rate of largescale structure that is complementary to the powerspectrum multipoles. In particular, we consider the multipoles of the line correlation function (LCF), which correlates phases between three collinear points, and use the Fisher forecasting method to show that the LCF multipoles can break the degeneracy between the measurement of the growth rate of structure f and the amplitude of perturbations σ_{8} that is present in the powerspectrum multipoles at large scales. This leads to an improvement in the measurement of f and σ_{8} by up to 220 per cent for $k_{\rm max} = 0.15 \, h\, \mathrm{Mpc}^{1}$ and up to 50 per cent for $k_{\rm max} = 0.30 \, h\, \mathrm{Mpc}^{1}$ at redshift z = 0.25, with respect to powerspectrum measurements alone for the upcoming generation of galaxy surveys like DESI and Euclid. The average improvements in the constraints on f and σ_{8} for $k_{\rm max} = 0.15 \, h\, \mathrm{Mpc}^{1}$ are ∼90 per cent for the DESI BGS sample with mean redshift $\overline{z}=0.25$ , ∼40 per cent for the DESI ELG sample with $\overline{z}=1.25$ , and ∼40 per cent for the Euclid Hα galaxies with $\overline{z}=1.3$ . For $k_{\rm max} = 0.30 \, h\, \mathrm{Mpc}^{1}$ , the average improvements are ∼40 per cent for the DESI BGS sample and ∼20 per cent for both the DESI ELG and Euclid Hα galaxies.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 July 2020
 DOI:
 10.1093/mnras/staa2020
 arXiv:
 arXiv:2005.06325
 Bibcode:
 2020MNRAS.497.1765B
 Keywords:

 Cosmology: theory;
 largescale structure of the Universe;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 28 pages, 13 figures, 2 tables. v2 has additional discussion on modelindependence of the forecasts. v3 matches the MNRAS accepted version