Designs for next generation CMB survey strategies from Chile

Abstract

New telescopes are being built to measure the Cosmic Microwave Background (CMB) with unprecedented sensitivity, including Simons Observatory (SO), CCAT-prime, the BICEP Array, SPT-3G, and CMB Stage-4. We present observing strategies for telescopes located in Chile that are informed by the tools used to develop recent Atacama Cosmology Telescope (ACT) and Polarbear surveys. As with ACT and Polarbear, these strategies are composed of scans that sweep in azimuth at constant elevation. We explore observing strategies for both small (0.42 m) aperture telescopes (SAT) and a large (6 m) aperture telescope (LAT). We study strategies focused on small sky areas to search for inflationary gravitational waves as well as strategies spanning roughly half the low-foreground sky to constrain the effective number of relativistic species and measure the sum of neutrino masses via the gravitational lensing signal due to large scale structure. We present these strategies specifically considering the telescope hardware and science goals of the SO, located at 23 degrees South latitude, 67.8 degrees West longitude. Observations close to the Sun and the Moon can introduce additional systematics by applying additional power to the instrument through telescope sidelobes. Significant side lobe contamination in the data can occur even at tens of degrees or more from bright sources. Therefore, we present several strategies that implement Sun and Moon avoidance constraints into the telescope scheduling. Strategies for resolving conflicts between simultaneously visible fields are discussed. We focus on maximizing telescope time spent on science observations. It will also be necessary to schedule calibration measurements, however that is beyond the scope of this work. The outputs of this study are algorithms that can generate specific schedule commands for the Simons Observatory instruments.

arXiv comment15 pages, 9 figures, 3 tables, SPIE Astronomical Telescopes + Instrumentation 2018

References in corpus (12)

• A Joint Analysis of BICEP2/Keck Array and Planck Data
• Mission design of LiteBIRD
• Second and third season QUaD CMB temperature and polarization power spectra
• Delensing the CMB with the Cosmic Infrared Background
• A general solution to the E-B mixing problem
• Making Maps Of The Cosmic Microwave Background: The MAXIMA Example
• The QUIET Instrument
• Survey strategy optimization for the Atacama Cosmology Telescope
• SPIDER: a balloon-borne CMB polarimeter for large angular scales
• Optimal scan strategies for future CMB satellite experiments
• Fast and precise map-making for massively multi-detector CMB experiments
• Making maps of Cosmic Microwave Background polarization for B-mode studies: the POLARBEAR example

Cited by in corpus (16)

• The Simons Observatory: Science goals and forecasts
• CMB lensing from Planck PR4 maps
• CCAT-prime Collaboration: Science Goals and Forecasts with Prime-Cam on the Fred Young Submillimeter Telescope
• The Simons Observatory: Instrument Overview
• The Atacama Cosmology Telescope: Microwave Intensity and Polarization Maps of the Galactic Center
• The Simons Observatory: Modeling Optical Systematics in the Large Aperture Telescope
• The Simons Observatory: Galactic Science Goals and Forecasts
• Optimal filtering for CMB lensing reconstruction
• BoloCalc: a sensitivity calculator for the design of Simons Observatory
• Instrumental systematics biases in CMB lensing reconstruction: a simulation-based assessment
• Spin characterisation of systematics in CMB surveys -- a comprehensive formalism
• Studies of Systematic Uncertainties for Simons Observatory: Optical Effects and Sensitivity Considerations
• Far Sidelobes from Baffles and Telescope Support Structures in the Atacama Cosmology Telescope
• Controlling systematics in ground-based CMB surveys with partial boresight rotation
• Galactic foreground constraints on primordial $B$-mode detection for ground-based experiments
• Fast map-based simulations of systematics in CMB surveys including effects of the scanning strategy