SPT-3G: A Next-Generation Cosmic Microwave Background Polarization Experiment on the South Pole Telescope

TL;DR

The SPT-3G experiment on the South Pole Telescope aims to significantly improve measurements of CMB polarization, enabling precise neutrino mass constraints and insights into the early universe, with enhanced sensitivity and synergy with other surveys.

Contribution

This paper introduces the design of the SPT-3G receiver, achieving a 20-fold increase in mapping speed and enabling high signal-to-noise polarization measurements for cosmological insights.

Findings

Enhanced sensitivity allows precise neutrino mass constraints (~0.06 eV).

Separation of lensing and inflationary B-mode signals improves primordial gravitational wave detection.

Synergy with optical surveys enhances large-scale structure and dark energy studies.

Abstract

We describe the design of a new polarization sensitive receiver, SPT-3G, for the 10-meter South Pole Telescope (SPT). The SPT-3G receiver will deliver a factor of ~20 improvement in mapping speed over the current receiver, SPTpol. The sensitivity of the SPT-3G receiver will enable the advance from statistical detection of B-mode polarization anisotropy power to high signal-to-noise measurements of the individual modes, i.e., maps. This will lead to precise (~0.06 eV) constraints on the sum of neutrino masses with the potential to directly address the neutrino mass hierarchy. It will allow a separation of the lensing and inflationary B-mode power spectra, improving constraints on the amplitude and shape of the primordial signal, either through SPT-3G data alone or in combination with BICEP-2/KECK, which is observing the same area of sky. The measurement of small-scale temperature anisotropy will provide new constraints on the epoch of reionization. Additional science from the SPT-3G survey will be significantly enhanced by the synergy with the ongoing optical Dark Energy Survey (DES), including: a 1% constraint on the bias of optical tracers of large-scale structure, a measurement of the differential Doppler signal from pairs of galaxy clusters that will test General Relativity on ~200 Mpc scales, and improved cosmological constraints from the abundance of clusters of galaxies.