Oral Presentation

The South Pole Telescope: Latest and upcoming results from the SPT-3G experiment and future plans

Author(s): Brad Benson (Chicago)

Presenter: Bradford Benson (University of Chicago, Fermilab)

The SPT-3G experiment on the South Pole Telescope (SPT) has been used to survey 10,000 sq deg of sky with an unprecedented combination of depth and angular resolution at 95, 150, and 220 GHz. Since 2019, SPT-3G has primarily observed a 1500 sq deg “Main” survey, however in 2024, SPT-3G completed a 10,000 sq deg “Wide” survey. The “Main” and “Wide” surveys have a coadded sensitivity of ~2 and 9 uK-arcmin, respectively, in CMB temperature units, and are expected to detect nearly 20,000 clusters of galaxies via the SZ effect. The first results from the “Main” survey have found ~6 clusters per sq deg, the highest density even measured in a SZ cluster survey, with ~23% and ~6% of the cluster sample confirmed at z > 1 and z > 1.6, respectively. I will describe the properties of this cluster sample, new larger samples soon to be released from the SPT-3G surveys, and the resultant future cosmological constraints from the cluster abundance and clustering. I will also describe upcoming CMB power spectrum measurements from SPT-3G, which will reduce the allowed volume of likelihood space in a LCDM cosmology by over a factor of 100 relative to Planck. I will also preview results from the combined SPT-3G and BICEP of the CMB B-mode polarization on degree-angular scales, which will improve constraints on Inflation via the tensor-to-scalar ratio by a factor of several in the next couple years. Finally, I will describe plans to increase the CMB sensitivity of SPT by nearly an order of magnitude with the new SPT-3G+ camera, planned to deploy at the end of 2028.