Results from the Atacama B-mode Search (ABS) experiment
Author
- Kusaka, Akito;
- Appel, John;
- Essinger-Hileman, Thomas;
- Beall, James A.;
- Campusano, Luis E.;
- Cho, Hsiao;
- Choi, Steve;
- Crowley, Kevin;
- Fowler, Joseph;
- Gallardo, Patricio;
- Hasselfield, Matthew;
- Hilton, Gene;
- Ho, Shuay;
- Irwin, Kent;
- Jarosik, Norman;
- Niemack, Michael;
- Nixon, Glen;
- Nolta, Michael;
- Page, Lyman;
- Palma, Gonzalo;
- Parker, Lucas;
- Raghunathan, Srinivasan;
- Reintsema, Carl;
- Sievers, Jonathan;
- Simon, Sara;
- Staggs, Suzanne;
- Visnjic, Katerina;
- Yoonh, Ki;
Abstract
The Atacama B-mode Search is an experiment designed to measure the cosmic
microwave background polarization at large angular scales (` > 40). 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 µK
√
s. 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
0.89 ± 0.10. 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.
Indexation
Artículo de publicación SCOPUS
Identifier
URI: https://repositorio.uchile.cl/handle/2250/169498
DOI: 10.1088/1475-7516/2018/09/005
ISSN: 14757516
Quote Item
Journal of Cosmology and Astroparticle Physics, Volumen 2018, Issue 9, 2018
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