Tightening geometric and dynamical constraints on dark energy and gravity: galaxy clustering, intrinsic alignment and kinetic Sunyaev-Zel'dovich effect

TL;DR

This paper demonstrates that combining galaxy clustering with velocity and intrinsic alignment measurements from kSZ and IA effects significantly enhances constraints on dark energy and gravity models, especially in non-flat cosmologies.

Contribution

It introduces a method to improve cosmological parameter constraints by integrating galaxy density, velocity, and tidal fields from multiple observational effects.

Findings

Adding kSZ and IA effects improves constraints on dark energy and gravity.

Non-flat models benefit most from combined analyses, with over 30% improvement.

Deep surveys outperform wide surveys when combined with these effects in certain models.

Abstract

Conventionally, in galaxy surveys, cosmological constraints on the growth and expansion history of the universe have been obtained from the measurements of redshift-space distortions and baryon acoustic oscillations embedded in the large-scale galaxy density field. In this paper, we study how well one can improve the cosmological constraints from the combination of the galaxy density field with velocity and tidal fields, which are observed via the kinetic Sunyaev-Zel'dovich (kSZ) and galaxy intrinsic alignment (IA) effects, respectively. For illustration, we consider the deep galaxy survey by Subaru Prime Focus Spectrograph, whose survey footprint perfectly overlaps with the imaging survey of the Hyper Suprime-Cam and the CMB-S4 experiment. We find that adding the kSZ and IA effects significantly improves cosmological constraints, particularly when we adopt the non-flat cold dark matter model which allows both time variation of the dark energy equation-of-state and deviation of the gravity law from general relativity. Under this model, we achieve $31\%$ improvement for the growth index $\gamma$ and $>35\%$ improvement for other parameters except for the curvature parameter, compared to the case of the conventional galaxy-clustering-only analysis. As another example, we also consider the wide galaxy survey by the {\it Euclid} satellite, in which shapes of galaxies are noisier but the survey volume is much larger. We demonstrate that when the above model is adopted, the clustering analysis combined with kSZ and IA from the deep survey can achieve tighter cosmological constraints than the clustering-only analysis from the wide survey.