A forecast of the sensitivity on the measurement of the optical depth to reionization with the GroundBIRD experiment

TL;DR

This paper predicts the GroundBIRD experiment's ability to measure the optical depth to reionization by simulating polarized sky maps and analyzing their sensitivity, showing potential improvements when combined with QUIJOTE data.

Contribution

It introduces a detailed simulation and analysis framework for estimating GroundBIRD's sensitivity to reionization optical depth, including multi-frequency data integration.

Findings

Sensitivity of σ_τ=0.030 for GroundBIRD alone

Improved sensitivity of σ_τ=0.012 when combined with QUIJOTE

Simulated polarization map noise levels at 145 and 220 GHz

Abstract

We compute the expected sensitivity on measurements of optical depth to reionization for a ground-based experiment at Teide Observatory. We simulate polarized partial sky maps for the GroundBIRD experiment at the frequencies 145 and 220 GHz. We perform fits for the simulated maps with our pixel-based likelihood to extract the optical depth to reionization. The noise levels of polarization maps are estimated as 110 $\mu\mathrm{K~arcmin}$ and 780 $ \mu\mathrm{K~arcmin}$ for 145 and 220 GHz, respectively, by assuming a three-year observing campaign and sky coverages of 0.537 for 145 GHz and 0.462 for 220 GHz. Our sensitivities for the optical depth to reionization are found to be $\sigma_\tau$=0.030 with the simulated GroundBIRD maps, and $\sigma_\tau$=0.012 by combining with the simulated QUIJOTE maps at 11, 13, 17, 19, 30, and 40 GHz.