We present constraints on the tensor-to-scalar ratio
r
using
Planck
data. We use the latest release of
Planck
maps, processed with the
NPIPE
code, which produces calibrated frequency maps in ...temperature and polarisation for all
Planck
channels from 30 GHz to 857 GHz using the same pipeline. We computed constraints on
r
using the
BB
angular power spectrum, and we also discuss constraints coming from the
TT
spectrum. Given
Planck
’s noise level, the
TT
spectrum gives constraints on
r
that are cosmic-variance limited (with
σ
r
= 0.093), but we show that the marginalised posterior peaks towards negative values of
r
at about the 1.2
σ
level. We derived
Planck
constraints using the
BB
power spectrum at both large angular scales (the ‘reionisation bump’) and intermediate angular scales (the ‘recombination bump’) from
ℓ
= 2 to 150 and find a stronger constraint than that from
TT
, with
σ
r
= 0.069. The
Planck
BB
spectrum shows no systematic bias and is compatible with zero, given both the statistical noise and the systematic uncertainties. The likelihood analysis using
B
modes yields the constraint
r
< 0.158 at 95% confidence using more than 50% of the sky. This upper limit tightens to
r
< 0.069 when
Planck
EE
,
BB
, and
EB
power spectra are combined consistently, and it tightens further to
r
< 0.056 when the
Planck
TT
power spectrum is included in the combination. Finally, combining
Planck
with BICEP2/Keck 2015 data yields an upper limit of
r
< 0.044.
We present constraints on the tensor-to-scalar ratio r using a combination of BICEP/Keck 2018 (BK18) and Planck PR4 data allowing us to fit for r consistently with the six parameters of the ΛCDM ...model. We discuss the sensitivity of constraints on r to uncertainties in the ΛCDM parameters as defined by the Planck data. In particular, we are able to derive a constraint on the reionization optical depth τ and thus propagate its uncertainty into the posterior distribution for r. While Planck sensitivity to r is slightly lower than the current ground-based measurements, the combination of Planck with BK18 and baryon-acoustic-oscillation data yields results consistent with r=0 and tightens the constraint to r<0.032 at 95% confidence.
We search for the signature of parity-violating physics in the cosmic microwave background, called cosmic birefringence, using the Planck data release 4. We initially find a birefringence angle of ...β=0.30°±0.11° (68% C.L.) for nearly full-sky data. The values of β decrease as we enlarge the Galactic mask, which can be interpreted as the effect of polarized foreground emission. Two independent ways to model this effect are used to mitigate the systematic impact on β for different sky fractions. We choose not to assign cosmological significance to the measured value of β until we improve our knowledge of the foreground polarization.
We present cosmological parameter constraints using maps from the last
Planck
data release (PR4). In particular, we detail an upgraded version of the cosmic microwave background likelihood,
HiLLiPoP
..., that is based on angular power spectra and relies on a physical modeling of the foreground residuals in the spectral domain. This new version of the likelihood retains a larger sky fraction (up to 75%) and uses an extended multipole range. Using this likelihood, along with low-
ℓ
measurements from
LoLLiPoP
, we derived constraints on ΛCDM parameters that are in good agreement with previous
Planck
2018 results, but with smaller uncertainties by 10% to 20%. We demonstrate that the foregrounds can be accurately described in the spectral domain, with a negligible impact on ΛCDM parameters. We also derived constraints on single-parameter extensions to ΛCDM, including
A
L
, Ω
K
,
N
eff
, and ∑
m
ν
. Noteworthy results from this updated analysis include a lensing amplitude value of
A
L
= 1.039 ± 0.052, which is more closely aligned with theoretical expectations within the ΛCDM framework. Additionally, our curvature measurement, Ω
K
= −0.012 ± 0.010, is now fully consistent with a flat universe and our measurement of
S
8
is closer to the measurements derived from large-scale structure surveys (at the 1.5
σ
level). We also added constraints from PR4 lensing, making this combination the most tightly constrained data set currently available from
Planck
. Additionally, we explored the addition of baryon acoustic oscillation data, which tightens the limits on some particular extensions to the standard cosmology.
We present a measurement of the B-mode polarization power spectrum of the cosmic microwave background (CMB) using data taken from 2014 July to 2016 December with the Polarbear experiment. The CMB ...power spectra are measured using observations at 150 GHz with an instantaneous array sensitivity of on a 670 square degree patch of sky centered at (R.A., decl.) = (+0h12m0s, −59°18′). A continuously rotating half-wave plate is used to modulate polarization and to suppress low-frequency noise. We achieve 32 K arcmin effective polarization map noise with a knee in sensitivity of = 90, where the inflationary gravitational-wave signal is expected to peak. The measured B-mode power spectrum is consistent with a ΛCDM lensing and single dust component foreground model over a range of multipoles 50 ≤ ≤ 600. The data disfavor zero at 2.2 using this range of Polarbear data alone. We cross-correlate our data with Planck full mission 143, 217, and 353 GHz frequency maps and find the low- B-mode power in the combined data set to be consistent with thermal dust emission. We place an upper limit on the tensor-to-scalar ratio r < 0.90 at the 95% confidence level after marginalizing over foregrounds.
Gravitational lensing due to the large-scale distribution of matter in the cosmos distorts the primordial cosmic microwave background (CMB) and thereby induces new, small-scale B-mode polarization. ...This signal carries detailed information about the distribution of all the gravitating matter between the observer and CMB last scattering surface. We report the first direct evidence for polarization lensing based on purely CMB information, from using the four-point correlations of even- and odd-parity E- and B-mode polarization mapped over ∼30 square degrees of the sky measured by the POLARBEAR experiment. These data were analyzed using a blind analysis framework and checked for spurious systematic contamination using null tests and simulations. Evidence for the signal of polarization lensing and lensing B modes is found at 4.2σ (stat+sys) significance. The amplitude of matter fluctuations is measured with a precision of 27%, and is found to be consistent with the Lambda cold dark matter cosmological model. This measurement demonstrates a new technique, capable of mapping all gravitating matter in the Universe, sensitive to the sum of neutrino masses, and essential for cleaning the lensing B-mode signal in searches for primordial gravitational waves.
BEYONDPLANCK Galloway, M.; Andersen, K. J.; Aurlien, R. ...
Astronomy and astrophysics (Berlin),
06/2023, Letnik:
675
Journal Article
Recenzirano
Odprti dostop
We describe the computational infrastructure for end-to-end Bayesian cosmic microwave background (CMB) analysis implemented by the BeyondPlanck Collaboration. The code is called
Commander3
. It ...provides a statistically consistent framework for global analysis of CMB and microwave observations and may be useful for a wide range of legacy, current, and future experiments. The paper has three main goals. Firstly, we provide a high-level overview of the existing code base, aiming to guide readers who wish to extend and adapt the code according to their own needs or re-implement it from scratch in a different programming language. Secondly, we discuss some critical computational challenges that arise within any global CMB analysis framework, for instance in-memory compression of time-ordered data, fast Fourier transform optimization, and parallelization and load-balancing. Thirdly, we quantify the CPU and RAM requirements for the current B
EYOND
P
LANCK
analysis, finding that a total of 1.5 TB of RAM is required for efficient analysis and that the total cost of a full Gibbs sample for LFI is 170 CPU-hrs, including both low-level processing and high-level component separation, which is well within the capabilities of current low-cost computing facilities. The existing code base is made publicly available under a GNU General Public Library (GPL) license.
BEYONDPLANCK Andersen, K. J.; Herman, D.; Aurlien, R. ...
Astronomy and astrophysics (Berlin),
06/2023, Letnik:
675
Journal Article
Recenzirano
Odprti dostop
We present the intensity foreground algorithms and model employed within the B
EYOND
P
LANCK
analysis framework. The B
EYOND
P
LANCK
analysis is aimed at integrating component separation and ...instrumental parameter sampling within a global framework, leading to complete end-to-end error propagation in the
Planck
Low Frequency Instrument (LFI) data analysis. Given the scope of the B
EYOND
P
LANCK
analysis, a limited set of data is included in the component separation process, leading to foreground parameter degeneracies. In order to properly constrain the Galactic foreground parameters, we improve upon the previous
Commander
component separation implementation by adding a suite of algorithmic techniques. These algorithms are designed to improve the stability and computational efficiency for weakly constrained posterior distributions. These are: (1) joint foreground spectral parameter and amplitude sampling, building on ideas from M
IRAMARE
; (2) component-based monopole determination; (3) joint spectral parameter and monopole sampling; and (4) application of informative spatial priors for component amplitude maps. We find that the only spectral parameter with a significant signal-to-noise ratio using the current B
EYOND
P
LANCK
data set is the peak frequency of the anomalous microwave emission component, for which we find
ν
p
= 25.3 ± 0.5 GHz; all others must be constrained through external priors. Future works will be aimed at integrating many more data sets into this analysis, both map and time-ordered based, thereby gradually eliminating the currently observed degeneracies in a controlled manner with respect to both instrumental systematic effects and astrophysical degeneracies. When this happens, the simple LFI-oriented data model employed in the current work will need to be generalized to account for both a richer astrophysical model and additional instrumental effects. This work will be organized within the Open Science-based C
OSMOGLOBE
community effort.
BEYONDPLANCK Svalheim, T. L.; Zonca, A.; Andersen, K. J. ...
Astronomy and astrophysics (Berlin),
07/2023, Letnik:
675
Journal Article
Recenzirano
Odprti dostop
We discuss the treatment of bandpass and beam leakage corrections in the Bayesian B
EYOND
P
LANCK
cosmic microwave background (CMB) analysis pipeline as applied to the
Planck
LFI measurements. As a ...preparatory step, we first applied three corrections to the nominal LFI bandpass profiles, including the removal of a known systematic effect in the ground measuring equipment at 61 GHz, along with a smoothing of standing wave ripples and edge regularization. The main net impact of these modifications is an overall shift in the 70 GHz bandpass of +0.6 GHz. We argue that any analysis of LFI data products, either from
Planck
or B
EYOND
P
LANCK
, should use these new bandpasses. In addition, we fit a single free bandpass parameter for each radiometer of the form Δ
i
= Δ
0
+
δ
i
, where Δ
0
represents an absolute frequency shift per frequency band and
δ
i
is a relative shift per detector. The absolute correction is only fitted at 30 GHz, with a full
χ
2
-based likelihood, resulting in a correction of Δ
30
= 0.24 ± 0.03 GHz. The relative corrections were fitted using a spurious map approach that is fundamentally similar to the method pioneered by the WMAP team, but excluding the introduction of many additional degrees of freedom. All the bandpass parameters were sampled using a standard Metropolis sampler within the main B
EYOND
P
LANCK
Gibbs chain and the bandpass uncertainties were thus propagated to all other data products in the analysis. In summary, we find that our bandpass model significantly reduces leakage effects. For beam leakage corrections, we adopted the official
Planck
LFI beam estimates without any additional degrees of freedom and we only marginalized over the underlying sky model. We note that this is the first time that leakage from beam mismatch has been included for
Planck
LFI maps.
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