SPT-SLIM: A Line Intensity Mapping Pathfinder for the South Pole Telescope

TL;DR

SPT-SLIM is a pioneering experiment using on-chip spectrometers at the South Pole to map mm-wave line emissions, aiming to advance cosmological studies beyond current galaxy survey limits.

Contribution

This paper introduces the SPT-SLIM instrument, a novel on-chip filter-bank spectrometer array deployed on the South Pole Telescope for line intensity mapping.

Findings

Demonstration of on-chip filter-bank spectrometers in a field setting.

Expected sensitivity to CO line signals from redshift 0.5 to 2.

Operational deployment planned for 2023-24 summer at the South Pole.

Abstract

The South Pole Telescope Summertime Line Intensity Mapper (SPT-SLIM) is a pathfinder experiment that will demonstrate the use of on-chip filter-bank spectrometers for mm-wave line intensity mapping (LIM). The SPT-SLIM focal plane consists of 18 dual-polarization R=300 filter-bank spectrometers covering 120-180 GHz, coupled to aluminum kinetic inductance detectors. A compact cryostat holds the detectors at 100 mK and performs observations without removing the SPT-3G receiver. SPT-SLIM will be deployed to the 10-m South Pole Telescope for observations during the 2023-24 austral summer. We discuss the overall instrument design, expected detector performance and sensitivity to the LIM signal from CO at 0.5 < z < 2. The technology and observational techniques demonstrated by SPT-SLIM will enable next-generation LIM experiments that constrain cosmology beyond the redshift reach of galaxy surveys.