ACTPol: A polarization-sensitive receiver for the Atacama Cosmology Telescope

TL;DR

ACTPol is a polarization-sensitive receiver designed for the Atacama Cosmology Telescope to measure the cosmic microwave background's polarization, aiming to improve constraints on neutrino masses, inflation, and cosmic structure growth.

Contribution

This paper introduces the design and science goals of ACTPol, a new instrument for the ACT that enhances CMB polarization measurements for cosmological research.

Findings

Designed ACTPol receiver for ACT

Projected constraints on neutrino masses (~0.05 eV)

Potential for cross-correlation with optical surveys

Abstract

The six-meter Atacama Cosmology Telescope (ACT) in Chile was built to measure the cosmic microwave background (CMB) at arcminute angular scales. We are building a new polarization sensitive receiver for ACT (ACTPol). ACTPol will characterize the gravitational lensing of the CMB and aims to constrain the sum of the neutrino masses with ~0.05 eV precision, the running of the spectral index of inflation-induced fluctuations, and the primordial helium abundance to better than 1%. Our observing fields will overlap with the SDSS BOSS survey at optical wavelengths, enabling a variety of cross-correlation science, including studies of the growth of cosmic structure from Sunyaev-Zel'dovich observations of clusters of galaxies as well as independent constraints on the sum of the neutrino masses. We describe the science objectives and the initial receiver design.