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Proceedings Paper

Designs for next generation CMB survey strategies from Chile
Author(s): Jason R. Stevens; Neil Goeckner-Wald; Reijo Keskitalo; Nialh McCallum; Aamir Ali; Julian Borrill; Michael L. Brown; Yuji Chinone; Patricio A. Gallardo; Akito Kusaka; Adrian T. Lee; Jeff McMahon; Michael D. Niemack; Lyman Page; Giuseppe Puglisi; Maria Salatino; Suet Ying D. Mak; Grant Teply; Daniel B. Thomas; Eve M. Vavagiakis; Edward J. Wollack; Zhilei Xu; Ningfeng Zhu
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Paper 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° South latitude, 67.8° 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.

Scan strategies can also be a powerful tool to diagnose and mitigate instrumental systematics either by using multiple scans to average down systematics or by providing null tests to diagnose problems. We discuss methods for quantifying the ability of an observation strategy to achieve this.

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.

Paper Details

Date Published: 17 July 2018
PDF: 15 pages
Proc. SPIE 10708, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX, 1070841 (17 July 2018); doi: 10.1117/12.2313898
Show Author Affiliations
Jason R. Stevens, Cornell Univ. (United States)
Neil Goeckner-Wald, Univ. of California, Berkeley (United States)
Reijo Keskitalo, Lawrence Berkeley National Lab. (United States)
Nialh McCallum, The Univ. of Manchester (United Kingdom)
Aamir Ali, Univ. of California, Berkeley (United States)
Julian Borrill, Lawrence Berkeley National Lab. (United States)
Univ. of California, Berkeley (United States)
Michael L. Brown, The Univ. of Manchester (United Kingdom)
Yuji Chinone, Univ. of California, Berkeley (United States)
Patricio A. Gallardo, Cornell Univ. (United States)
Akito Kusaka, Lawrence Berkeley National Lab. (United States)
The Univ. of Tokyo (Japan)
Adrian T. Lee, Univ. of California, Berkeley (United States)
Lawrence Berkeley National Lab. (United States)
Jeff McMahon, Univ. of Michigan (United States)
Michael D. Niemack, Cornell Univ. (United States)
Lyman Page, Princeton Univ. (United States)
Giuseppe Puglisi, Stanford Univ. (United States)
Maria Salatino, AstroParticle and Cosmology Lab., Paris Diderot Univ. (United States)
Suet Ying D. Mak, Imperial College London (United Kingdom)
Grant Teply, Univ. of California, San Diego (United States)
Daniel B. Thomas, The Univ. of Manchester (United Kingdom)
Eve M. Vavagiakis, Cornell Univ. (United States)
Edward J. Wollack, NASA Goddard Space Flight Ctr. (United States)
Zhilei Xu, Univ. of Pennsylvania (United States)
Ningfeng Zhu, Univ. of Pennsylvania (United States)

Published in SPIE Proceedings Vol. 10708:
Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy IX
Jonas Zmuidzinas; Jian-Rong Gao, Editor(s)

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