TY - JOUR

T1 - Galaxy power spectrum in general relativity

AU - Grimm, Nastassia

AU - Scaccabarozzi, Fulvio

AU - Yoo, Jaiyul

AU - Biern, Sang Gyu

AU - Gong, Jinn Ouk

N1 - Publisher Copyright:
© 2020 IOP Publishing Ltd and Sissa Medialab.

PY - 2020/11

Y1 - 2020/11

N2 - We present the galaxy power spectrum in general relativity. Using a novel approach, we derive the galaxy power spectrum taking into account all the relativistic effects in observations. In particular, we show independently of survey geometry that relativistic effects yield no divergent terms (proportional to k-4Pm(k) or k-2Pm(k) on all scales) that would mimic the signal of primordial non-Gaussianity. This cancellation of such divergent terms is indeed expected from the equivalence principle, meaning that any perturbation acting as a uniform gravity on the scale of the experiment cannot be measured. We find that the unphysical infrared divergence obtained in previous calculations occurred only due to not considering all general relativistic contributions consistently. Despite the absence of divergent terms, general relativistic effects represented by non-divergent terms alter the galaxy power spectrum at large scales (smaller than the horizon scale). In our numerical computation of the full galaxy power spectrum, we show the deviations from the standard redshift-space power spectrum due to these non-divergent corrections. We conclude that, as relativistic effects significantly alter the galaxy power spectrum at k≲ keq, they need to be taken into account in the analysis of large-scale data.

AB - We present the galaxy power spectrum in general relativity. Using a novel approach, we derive the galaxy power spectrum taking into account all the relativistic effects in observations. In particular, we show independently of survey geometry that relativistic effects yield no divergent terms (proportional to k-4Pm(k) or k-2Pm(k) on all scales) that would mimic the signal of primordial non-Gaussianity. This cancellation of such divergent terms is indeed expected from the equivalence principle, meaning that any perturbation acting as a uniform gravity on the scale of the experiment cannot be measured. We find that the unphysical infrared divergence obtained in previous calculations occurred only due to not considering all general relativistic contributions consistently. Despite the absence of divergent terms, general relativistic effects represented by non-divergent terms alter the galaxy power spectrum at large scales (smaller than the horizon scale). In our numerical computation of the full galaxy power spectrum, we show the deviations from the standard redshift-space power spectrum due to these non-divergent corrections. We conclude that, as relativistic effects significantly alter the galaxy power spectrum at k≲ keq, they need to be taken into account in the analysis of large-scale data.

UR - http://www.scopus.com/inward/record.url?scp=85097679667&partnerID=8YFLogxK

U2 - 10.1088/1475-7516/2020/11/064

DO - 10.1088/1475-7516/2020/11/064

M3 - Article

AN - SCOPUS:85097679667

SN - 1475-7516

VL - 2020

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

IS - 11

M1 - 064

ER -