Year two instrument status of the SPT-3G cosmic microwave background receiver

Abstract

The South Pole Telescope (SPT) is a millimeter-wavelength telescope designed for high-precision measurements of the cosmic microwave background (CMB). The SPT measures both the temperature and polarization of the CMB with a large aperture, resulting in high resolution maps sensitive to signals across a wide range of angular scales on the sky. With these data, the SPT has the potential to make a broad range of cosmological measurements. These include constraining the effect of massive neutrinos on large-scale structure formation as well as cleaning galactic and cosmological foregrounds from CMB polarization data in future searches for inflationary gravitational waves. The SPT began observing in January 2017 with a new receiver (SPT-3G) containing ∼16,000 polarizationsensitive transition-edge sensor bolometers. Several key technology developments have enabled this large-format focal plane, including advances in detectors, readout electronics, and large millimeter-wavelength optics. We discuss the implementation of these technologies in the SPT-3G receiver as well as the challenges they presented. In late 2017 the implementations of all three of these technologies were modified to optimize total performance. Here, we present the current instrument status of the SPT-3G receiver.

The baryon content of groups and clusters of galaxies in the FABLE simulations

“…Upcoming SZ cluster surveys are expected to identify an unprecedented number of low-mass clusters and galaxy groups out to high redshift (e.g. Benson et al 2014;Henderson et al 2016;Abazajian et al 2016;Bender et al 2018). For example, ongoing and future SZ-selected surveys such as SPT-3G (Benson et al 2014) and CMB-S4 (Abazajian et al 2016) are expected to be mass-limited at a level of M500 10 14 M .…”

Consistency of Planck, ACT and SPT constraints on magnetically assisted recombination and forecasts for future experiments

“…For the forecast presented in this section, we consider five observation seasons (2019-2023 included), which will use all ∼16,000 detectors on the main survey field (∼1500 deg 2 , f sky ∼ 0.03). We include three frequency bands, 95, 150, and 220 GHz, in both intensity and polarization, with beam full-width half-maximum (FWHM) of 1.7, 1.2, and 1.1 arcminutes (arcmin), respectively, and projected white noise levels in temperature of 3.0, 2.2, and 8.8 µK-arcmin (a factor of √ 2 higher in polarization) [87,116]. The noise curves also include the atmospheric 1/ f noise and account for foreground residuals.…”

Breaking the degeneracy between polarization efficiency and cosmological parameters in CMB experiments

“…In this section, we forecast how well P cal could be measured with our method and the impact on cosmological parameter uncertainties when marginalizing over P cal for ongoing and future experiments. We consider two experiment configurations: SPT-3G, the third-generation camera currently installed on the South Pole Telescope [13,30], and CMB-S4, a nextgeneration ground-based CMB experiment [17].…”

“…Therefore, for this forecast, we use noise level projections starting from 2019 when the active detector count nearly doubled. With five seasons of observations on the main survey field (2019-2023 inclusive), the noise levels in the final coadded temperature maps are projected to be 3.0, 2.2, and 8.8 µK arcmin in the three frequency bands, and those in the polarization maps are a factor of √ 2 higher [13,30].…”

“…For this reason, the ability to self-calibrate P cal with only TE and EE as demonstrated by this work is of particular interest to current and upcoming ground-based experiments [e.g. [13][14][15][16][17].…”