@article{e963bf05ba5b4db594b259533d995180,
title = "Results from the Atacama B-mode Search (ABS) experiment",
abstract = "The Atacama B-mode Search is an experiment designed to measure the cosmic microwave background polarization at large angular scales (0ℓ>4). It observes at 145 GHz from a site at 5,190 m elevation in northern Chile. The noise equivalent polarization temperature, or NEQ, is 41 μKs. One of the unique features of ABS is its use of a rapidly rotating ambient-temperature half-wave plate (HWP) {as the first optical element}. {The HWP spins} at 2.55 Hz to modulate the incident polarized signal at frequencies above where instrument white noise dominates over atmospheric fluctuations and other sources of low-frequency noise. We report here on the analysis of data from a 2,400 deg2 region of sky. We perform a blind analysis to reduce potential bias. After unblinding, we find agreement with the Planck TE and EE measurements on the same region of sky, {with a derived calibration factor of 00.89 ± 0.1}. We marginally detect polarized dust emission {(at 3.2 σ for EE and 2.2 σ for BB)} and give an upper limit on the tensor-to-scalar ratio of r<2.3 (95% confidence level) with the equivalent of 100 on-sky days of observation. We also present a new measurement of the polarization of Tau A and introduce new methods for calibration and data analysis associated with HWP-based observations.",
keywords = "CMBR experiments, CMBR polarization, gravitational waves and CMBR polarization, physics of the early universe",
author = "Akito Kusaka and John Appel and Thomas Essinger-Hileman and Beall, {James A.} and Campusano, {Luis E.} and Cho, {Hsiao Mei} and Choi, {Steve K.} and Kevin Crowley and Fowler, {Joseph W.} and Patricio Gallardo and Matthew Hasselfield and Gene Hilton and Ho, {Shuay Pwu P.} and Kent Irwin and Norman Jarosik and Niemack, {Michael D.} and Nixon, {Glen W.} and Michael Snolta and Page, {Lyman A.} and Palma, {Gonzalo A.} and Lucas Parker and Srinivasan Raghunathan and Reintsema, {Carl D.} and Jonathan Sievers and Simon, {Sara M.} and Staggs, {Suzanne T.} and Katerina Visnjic and Yoon, {Ki Won}",
note = "Funding Information: The ABS experiment began in 2006. This work was supported by the U.S. National Science Foundation through awards PHY-0355328, PHY-0855887, and PHY-1214379; and by the U.S. National Aeronautics and Space Administration through award NNX08AE03G. Funding was also provided by Princeton University and a Canada Foundation for Innovation (CFI) award to UBC. ABS operated in the Parque Astron{\'o}mico Atacama in northern Chile under the auspices of the Comisi{\'o}n Nacional de Investigaci{\'o}n Cient{\'i}fica y Tecnol{\'o}gica de Chile (CONICYT). Computations were performed on the GPC supercomputer at the SciNet HPC Consortium. SciNet is funded by the CFI under the auspices of Compute Canada, the Government of Ontario, the Ontario Research Fund: Research Excellence; and the University of Toronto. Work at LBNL is supported in part by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under contract No. DE-AC02-05CH11231. TEH was supported by a National Defense Science and Engineering Graduate Fellowship, as well as a National Science Foundation Astronomy and Astrophysics Postdoctoral Fellowship. SMS and KC gratefully acknowledge support from NSTRF Fellowships. SR acknowledges the CONICYT PhD studentship and support from Australian Research Council{\textquoteright}s Discovery Projects scheme (DP150103208). LEC acknowledges partial support from CONICYT Anillo project ACT-1122 and the Center of Excellence in Astrophysics and Associated Technologies (PFB06). AK acknowledges the support as a Dicke Fellow at Princeton University, and by JSPS KAKENHI Grant Number JP16K21744 and JSPS Leading Initiative for Excellent Young Researchers (LEADER). We thank the Mishrahi Fund and the Wilkinson Fund for generous support of the project. Publisher Copyright: {\textcopyright} 2018 IOP Publishing Ltd and Sissa Medialab.",
year = "2018",
month = sep,
day = "4",
doi = "10.1088/1475-7516/2018/09/005",
language = "English (US)",
volume = "2018",
journal = "Journal of Cosmology and Astroparticle Physics",
issn = "1475-7516",
publisher = "IOP Publishing Ltd.",
number = "9",
}