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Tensor-to-scalar ratio forecasts for extended LiteBIRD frequency configurationsLiteBIRD is a planned JAXA-led cosmic microwave background (CMB) B-mode satellite experiment aiming for launch in the late 2020s, with a primary goal of detecting the imprint of primordial inflationary gravitational waves. Its current baseline focal-plane configuration includes 15 frequency bands between 40 and 402 GHz, fulfilling the mission requirements to detect the amplitude of gravitational waves with the total uncertainty on the tensor-to-scalar ratio, δr, down to δr < 0.001. A key aspect of this performance is accurate astrophysical component separation, and the ability to remove polarized thermal dust emission is particularly important. In this paper we note that the CMB frequency spectrum falls off nearly exponentially above 300 GHz relative to the thermal dust spectral energy distribution, and a relatively minor high frequency extension can therefore result in even lower uncertainties and better model reconstructions. Specifically, we compared the baseline design with five extended configurations, while varying the underlying dust modeling, in each of which the High-Frequency Telescope (HFT) frequency range was shifted logarithmically toward higher frequencies, with an upper cutoff ranging between 400 and 600 GHz. In each case, we measured the tensor-to-scalar ratio r uncertainty and bias using both parametric and minimum-variance component-separation algorithms. When the thermal dust sky model includes a spatially varying spectral index and temperature, we find that the statistical uncertainty on r after foreground cleaning may be reduced by as much as 30–50% by extending the upper limit of the frequency range from 400 to 600 GHz, with most of the improvement already gained at 500 GHz. We also note that a broader frequency range leads to higher residuals when fitting an incorrect dust model, but also it is easier to discriminate between models through higher χ2 sensitivity. Even in the case in which the fitting procedure does not correspond to the underlying dust model in the sky, and when the highest frequency data cannot be modeled with sufficient fidelity and must be excluded from the analysis, the uncertainty on r increases by only about 5% for a 500 GHz configuration compared to the baseline.
Document ID
20230011910
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
U. Fuskeland
(University of Oslo Oslo, Norway)
J. Aumont ORCID
(University of Toulouse II - Le Mirail Toulouse, France)
R. Aurlien
(University of Oslo Oslo, Norway)
C. Baccigalupi
(Scuola Internazionale Superiore di Studi Avanzati Trieste, Italy)
A. J. Banday
(University of Toulouse II - Le Mirail )
H. K. Eriksen
(Institute of Theoretical Astrophysics, University of Oslo, Blindern, Oslo, Norway)
J. Errard ORCID
(French National Centre for Scientific Research Paris, France)
R. T. Génova-Santos
(Instituto de Astrofísica de Canarias Tenerife, Spain)
T. Hasebe
(Kavli Institute for the Physics and Mathematics of the Universe Kashiwa, Japan)
J. Hubmayr
(NIST Quantum Sensors Group )
H. Imada
(National Astronomical Observatory of Japan Mitaka-shi, Japan)
N. Krachmalnicof
(Scuola Internazionale Superiore di Studi Avanzati Trieste, Italy)
L. Lamagna
(Sapienza University of Rome Rome, Lazio, Italy)
G. Pisano
(Sapienza University of Rome Rome, Lazio, Italy)
D. Poletti
(University of Milano-Bicocca Milan, Italy)
M. Remazeilles ORCID
(Instituto de Física de Cantabria Santander, Spain)
K. L. Thompson
(SLAC National Accelerator Laboratory Menlo Park, United States)
L. Vache
(Université de Toulouse Toulouse, France)
I. K. Wehus
(University of Oslo Oslo, Norway)
S. Azzoni
(University of Oxford Oxford, United Kingdom)
M. Ballardini
(Universitá di Ferrara )
R. B. Barreiro
(Instituto de Fisica de Cantabria )
N. Bartolo
(Universitá degli Studi di Padova )
A. Basyrov
(University of Oslo Oslo, Norway)
D. Beck
(Stanford University Stanford, United States)
M. Bersanelli
(Universitá degli Studi di Milano )
M. Bortolami
(Universitá di Ferrara )
M. Brilenkov
(University of Oslo Oslo, Norway)
E. Calabrese ORCID
(Cardiff University Cardiff, United Kingdom)
A. Carones
(Universitá di Roma Tor Vergata )
F. J. Casas
(Instituto de Fisica de Cantabria )
K. Cheung
(University of California, Berkeley Berkeley, United States)
J. Chluba
(Jodrell Bank Centre for Astrophysics )
S. E. Clark
(Stanford University Stanford, United States)
L. Clermont
(University of Liège Liège, Belgium)
E.J. Wollack
(Goddard Space Flight Center Greenbelt, Maryland, United States)
Date Acquired
August 10, 2023
Publication Date
August 4, 2023
Publication Information
Publication: Astronomy & Astrophysics
Publisher: EDP Sciences
Volume: 676
Subject Category
Space Sciences (General)
Funding Number(s)
WBS: 920121
Distribution Limits
Public
Copyright
Portions of document may include copyright protected material.
Technical Review
External Peer Committee
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