Cosmological parameter forecasts by a joint 2D tomographic approach to CMB and galaxy clustering

Abstract

The cross-correlation between the cosmic microwave background (CMB) fields and matter tracers carries important cosmological information. In this paper, we forecast by a signal-to-noise ratio analysis the information contained in the cross-correlation of the CMB anisotropy fields with source counts for future cosmological observations and its impact on cosmological parameters uncertainties, using a joint tomographic analysis. We include temperature, polarization and lensing for the CMB fields and galaxy number counts for the matter tracers. We consider P lanck-like, the Simons Observatory, LiteBIRD and CMB-S4 specifications for CMB, and Euclid-like, Vera C. Rubin Observatory, SPHEREx, EMU and SKA1 for future galaxy surveys. We restrict ourselves to quasi-linear scales in order to deliver results which are free as much as possible from the uncertainties in modelling nonlinearities. We forecast by a Fisher matrix formalism the relative importance of the cross-correlation of source counts with the CMB in the constraints on the parameters for several cosmological models. We obtain that the CMB-number counts cross-correlation can improve the dark energy Figure of Merit (FoM) at most up to a factor ∼ 2 for LiteBIRD+CMB-S4 × SKA1 compared to the uncorrelated combination of both probes and will enable the Euclid-like photometric survey to reach the highest FoM among those considered here. We also forecast how CMB-galaxy clustering crosscorrelation could increase the FoM of the neutrino sector, also enabling a statistically significant ( 3σ for LiteBIRD+CMB-S4 × SPHEREx) detection of the minimal neutrino mass allowed in a normal hierarchy by using quasi-linear scales only. Analogously, we find that the uncertainty in the local primordial non-Gaussianity could be as low as σ(fNL) ∼ 1.5 − 2 by using two-point statistics only with the combination of CMB and radio surveys such as EMU and SKA1. Further, we quantify how cross-correlation will help characterizing the galaxy bias. Our results highlight the additional constraining power of the cross-correlation between CMB and galaxy clustering from future surveys which is mainly based on quasi-linear scales and therefore sufficiently robust to non-linear effects.

Constraining primordial non-Gaussianity by combining next-generation galaxy and 21 cm intensity mapping surveys

“…1 [47][48][49][50][51][52][53][54][55][56][57][58][59][60]. The performance of the multi-tracer improves when the difference in tracer properties, especially the Gaussian clustering biases, is significant.…”

Tachyonic cosmology with cubic contractions of the Riemann tensor

“…The consistent description and analysis of this phenomena is expected to offer new insights and revolutions in the modern cosmology, having specific effects in the development of various physical theories and technologies. Since the discovery, the accelerated expansion have been probed through various astrophysical studies [15][16][17][18][19].…”