The Cosmology Large Angular Scale Surveyor

Abstract

The Cosmology Large Angular Scale Surveyor (CLASS) is a four telescope array designed to characterize relic primordial gravitational waves from inflation and the optical depth to reionization through a measurement of the polarized cosmic microwave background (CMB) on the largest angular scales. The frequencies of the four CLASS telescopes, one at 38 GHz, two at 93 GHz, and one dichroic system at 145/217 GHz, are chosen to avoid spectral regions of high atmospheric emission and span the minimum of the polarized Galactic foregrounds: synchrotron emission at lower frequencies and dust emission at higher frequencies. Low-noise transition edge sensor detectors and a rapid front-end polarization modulator provide a unique combination of high sensitivity, stability, and control of systematics. The CLASS site, at 5200 m in the Chilean Atacama desert, allows for daily mapping of up to 70\% of the sky and enables the characterization of CMB polarization at the largest angular scales. Using this combination of a broad frequency range, large sky coverage, control over systematics, and high sensitivity, CLASS will observe the reionization and recombination peaks of the CMB E- and B-mode power spectra. CLASS will make a cosmic variance limited measurement of the optical depth to reionization and will measure or place upper limits on the tensor-to-scalar ratio, $r$, down to a level of 0.01 (95\% C.L.).

References in corpus (11)

• SPT-3G: A Next-Generation Cosmic Microwave Background Polarization Experiment on the South Pole Telescope
• CLASS: The Cosmology Large Angular Scale Surveyor
• Measurements of Sub-degree B-mode Polarization in the Cosmic Microwave Background from 100 Square Degrees of SPTpol Data
• BICEP3: a 95 GHz refracting telescope for degree-scale CMB polarization
• The Cosmology Large Angular Scale Surveyor
• The Cosmology Large Angular Scale Surveyor (CLASS): 40 GHz optical design
• Background reionization history from omniscopes
• The Cosmology Large Angular Scale Surveyor (CLASS): 38 GHz detector array of bolometric polarimeters
• The Primordial Inflation Polarization Explorer (PIPER)
• Silicon-Based Antenna-Coupled Polarization-Sensitive Millimeter-Wave Bolometer Arrays for Cosmic Microwave Background Instruments
• Scalable background-limited polarization-sensitive detectors for mm-wave applications

Cited by in corpus (5)

• CMB-S4 Science Case, Reference Design, and Project Plan
• The Cosmology Large Angular Scale Surveyor
• The Cosmology Large Angular Scale Surveyor (CLASS): 38 GHz detector array of bolometric polarimeters
• Readout of two-kilopixel transition-edge sensor arrays for Advanced ACTPol
• The Large Number Limit of Multifield Inflation