Planck 2018 results Akrami, Y.; Aumont, J.; Baccigalupi, C. ...
Astronomy and astrophysics (Berlin),
09/2020, Letnik:
641
Journal Article
Recenzirano
Odprti dostop
We report on the implications for cosmic inflation of the 2018 release of the Planck cosmic microwave background (CMB) anisotropy measurements. The results are fully consistent with those reported ...using the data from the two previous Planck cosmological releases, but have smaller uncertainties thanks to improvements in the characterization of polarization at low and high multipoles. Planck temperature, polarization, and lensing data determine the spectral index of scalar perturbations to be n s = 0.9649 ± 0.0042 at 68% CL. We find no evidence for a scale dependence of n s , either as a running or as a running of the running. The Universe is found to be consistent with spatial flatness with a precision of 0.4% at 95% CL by combining Planck with a compilation of baryon acoustic oscillation data. The Planck 95% CL upper limit on the tensor-to-scalar ratio, r 0.002 < 0.10, is further tightened by combining with the BICEP2/Keck Array BK15 data to obtain r 0.002 < 0.056. In the framework of standard single-field inflationary models with Einstein gravity, these results imply that: (a) the predictions of slow-roll models with a concave potential, V ″( ϕ ) < 0, are increasingly favoured by the data; and (b) based on two different methods for reconstructing the inflaton potential, we find no evidence for dynamics beyond slow roll. Three different methods for the non-parametric reconstruction of the primordial power spectrum consistently confirm a pure power law in the range of comoving scales 0.005 Mpc −1 ≲ k ≲ 0.2 Mpc −1 . A complementary analysis also finds no evidence for theoretically motivated parameterized features in the Planck power spectra. For the case of oscillatory features that are logarithmic or linear in k , this result is further strengthened by a new combined analysis including the Planck bispectrum data. The new Planck polarization data provide a stringent test of the adiabaticity of the initial conditions for the cosmological fluctuations. In correlated, mixed adiabatic and isocurvature models, the non-adiabatic contribution to the observed CMB temperature variance is constrained to 1.3%, 1.7%, and 1.7% at 95% CL for cold dark matter, neutrino density, and neutrino velocity, respectively. Planck power spectra plus lensing set constraints on the amplitude of compensated cold dark matter-baryon isocurvature perturbations that are consistent with current complementary measurements. The polarization data also provide improved constraints on inflationary models that predict a small statistically anisotropic quadupolar modulation of the primordial fluctuations. However, the polarization data do not support physical models for a scale-dependent dipolar modulation. All these findings support the key predictions of the standard single-field inflationary models, which will be further tested by future cosmological observations.
BEYONDPLANCK Basyrov, A.; Suur-Uski, A.-S.; Colombo, L. P. L. ...
Astronomy and astrophysics (Berlin),
06/2023, Letnik:
675
Journal Article
Recenzirano
Odprti dostop
We present
Planck
Low Frequency Instrument (LFI) frequency sky maps derived within the B
EYOND
P
LANCK
framework. This framework draws samples from a global posterior distribution that includes ...instrumental, astrophysical, and cosmological parameters, and the main product is an entire ensemble of frequency sky map samples, each of which corresponds to one possible realization of the various modeled instrumental systematic corrections, including correlated noise, time-variable gain, as well as far sidelobe and bandpass corrections. This ensemble allows for computationally convenient end-to-end propagation of low-level instrumental uncertainties into higher-level science products, including astrophysical component maps, angular power spectra, and cosmological parameters. We show that the two dominant sources of LFI instrumental systematic uncertainties are correlated noise and gain fluctuations, and the products presented here support – for the first time – full Bayesian error propagation for these effects at full angular resolution. We compared our posterior mean maps with traditional frequency maps delivered by the Planck Collaboration, and find generally good agreement. The most important quality improvement is due to significantly lower calibration uncertainties in the new processing, as we find a fractional absolute calibration uncertainty at 70 GHz of Δ
g
0
/
g
0
= 5 × 10
−5
, which is nominally 40 times smaller than that reported by
Planck
2018. However, we also note that the original
Planck
2018 estimate has a nontrivial statistical interpretation, and this further illustrates the advantage of the new framework in terms of producing self-consistent and well-defined error estimates of all involved quantities without the need of ad hoc uncertainty contributions. We describe how low-resolution data products, including dense pixel-pixel covariance matrices, may be produced from the posterior samples directly, without the need for computationally expensive analytic calculations or simulations. We conclude that posterior-based frequency map sampling provides unique capabilities in terms of low-level systematics modeling and error propagation, and may play an important role for future Cosmic Microwave Background (CMB)
B
-mode experiments aiming at nanokelvin precision.
BEYONDPLANCK Paradiso, S.; Colombo, L. P. L.; Andersen, K. J. ...
Astronomy and astrophysics (Berlin),
06/2023, Letnik:
675
Journal Article
Recenzirano
Odprti dostop
We present cosmological parameter constraints estimated using the Bayesian B
EYOND
P
LANCK
analysis framework. This method supports seamless end-to-end error propagation from raw time-ordered data ...onto final cosmological parameters. As a first demonstration of the method, we analyzed time-ordered
Planck
LFI observations, combined with selected external data (WMAP 33–61 GHz,
Planck
HFI DR4 353 and 857 GHz, and Haslam 408 MHz) in the form of pixelized maps that are used to break critical astrophysical degeneracies. Overall, all the results are generally in good agreement with previously reported values from
Planck
2018 and WMAP, with the largest relative difference for any parameter amounting about 1
σ
when considering only temperature multipoles between 30 ≤
ℓ
≤ 600. In cases where there are differences, we note that the B
EYOND
P
LANCK
results are generally slightly closer to the high-
ℓ
HFI-dominated
Planck
2018 results than previous analyses, suggesting slightly less tension between low and high multipoles. Using low-
ℓ
polarization information from LFI and WMAP, we find a best-fit value of
τ
= 0.066 ± 0.013, which is higher than the low value of
τ
= 0.052 ± 0.008 derived from
Planck
2018 and slightly lower than the value of 0.069 ± 0.011 derived from the joint analysis of official LFI and WMAP products. Most importantly, however, we find that the uncertainty derived in the B
EYOND
P
LANCK
processing is about 30 % greater than when analyzing the official products, after taking into account the different sky coverage. We argue that this uncertainty is due to a marginalization over a more complete model of instrumental and astrophysical parameters, which results in more reliable and more rigorously defined uncertainties. We find that about 2000 Monte Carlo samples are required to achieve a robust convergence for a low-resolution cosmic microwave background (CMB) covariance matrix with 225 independent modes, and producing these samples takes about eight weeks on a modest computing cluster with 256 cores.
BEYONDPLANCK Keihänen, E.; Suur-Uski, A.-S.; Andersen, K. J. ...
Astronomy and astrophysics (Berlin),
06/2023, Letnik:
675
Journal Article
Recenzirano
Odprti dostop
We present a Gibbs sampling solution to the mapmaking problem for cosmic microwave background (CMB) measurements that builds on existing destriping methodology. Gibbs sampling breaks the ...computationally heavy destriping problem into two separate steps: noise filtering and map binning. Considered as two separate steps, both are computationally much cheaper than solving the combined problem. This provides a huge performance benefit as compared to traditional methods and it allows us, for the first time, to bring the destriping baseline length to a single sample. Here, we applied the Gibbs procedure to simulated
Planck
30 GHz data. We find that gaps in the time-ordered data are handled efficiently by filling them in with simulated noise as part of the Gibbs process. The Gibbs procedure yields a chain of map samples, from which we are able to compute the posterior mean as a best-estimate map. The variation in the chain provides information on the correlated residual noise, without the need to construct a full noise covariance matrix. However, if only a single maximum-likelihood frequency map estimate is required, we find that traditional conjugate gradient solvers converge much faster than a Gibbs sampler in terms of the total number of iterations. The conceptual advantages of the Gibbs sampling approach lies in statistically well-defined error propagation and systematic error correction. This methodology thus forms the conceptual basis for the mapmaking algorithm employed in the B
EYOND
P
LANCK
framework, which implements the first end-to-end Bayesian analysis pipeline for CMB observations.
Field experiments have shown that information nudging can help households to save energy, however, the effectiveness varies depending on aspects such as information content, delivery mode and study ...area. This article evaluates the impacts of information nudges on residential electricity consumption with a randomized field experiment. This opt-in experiment was conducted in Finland. Information was administered via monthly email newsletters and an online energy service platform. The aim is to find out whether i) energy saving tips combined with and without online energy service platform providing electricity consumption information, and ii) peer comparisons (i.e., social norm) influence households’ electricity consumption. The results show a high seasonal variation in the treatment effects within the groups who were registered users of the online energy service platform. Those with access to usage feedback and versatile energy savings tips (without the social norm comparisons) reduced their electricity consumption around 10% in wintertime. The results imply challenges in encouraging energy saving behavior among households less interested in following their electricity consumption.
•Randomized field trial focusing on nudging and residential electricity consumption.•Examined nudges include energy saving tips and peer comparisons.•Interest in monitoring electricity consumption is linked with nudge efficacy.•Email delivered energy saving tips reduce electricity consumption in wintertime.
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.
The Planck Collaboration made its final data release in 2018. In this paper we describe beam-deconvolution map products made from Planck Low Frequency Instrument (LFI) data using the artDeco ...deconvolution code to symmetrize the effective beam. The deconvolution results are auxiliary data products, available through the Planck Legacy Archive. Analysis of these deconvolved survey difference maps reveals signs of residual signal in the 30 GHz and 44 GHz frequency channels. We produce low-resolution maps and corresponding noise covariance matrices (NCVMs). The NCVMs agree reasonably well with the half-ring noise estimates except for 44 GHz, where we observe an asymmetry between EE and BB noise spectra, possibly a sign of further unresolved systematic error. In contrast to the official Planck LFI maps, the beam-deconvolution maps have not been corrected for bandpass mismatch, and the residual noise is not well approximated by white noise.
Planck intermediate results Adam, R; Aghanim, N; Ashdown, M ...
Astronomy and astrophysics (Berlin),
12/2016, Letnik:
596
Journal Article
Recenzirano
Odprti dostop
We investigate constraints on cosmic reionization extracted from the Planck cosmic microwave background (CMB) data. We combine the Planck CMB anisotropy data in temperature with the low-multipole ...polarization data to fit LambdaCDM models with various parameterizations of the reionization history. We obtain a Thomson optical depth tau= 0.058 + or - 0.012 for the commonly adopted instantaneous reionization model. This confirms, with data solely from CMB anisotropies, the low value suggested by combining Planck 2015 results with other data sets, and also reduces the uncertainties. We reconstruct the history of the ionization fraction using either a symmetric or an asymmetric model for the transition between the neutral and ionized phases. To determine better constraints on the duration of the reionization process, we also make use of measurements of the amplitude of the kinetic Sunyaev-Zeldovich (kSZ) effect using additional information from the high-resolution Atacama Cosmology Telescope and South Pole Telescope experiments. The average redshift at which reionization occurs is found to lie between z= 7.8 and 8.8, depending on the model of reionization adopted. Using kSZ constraints and a redshift-symmetric reionization model, we find an upper limit to the width of the reionization period of Deltaz< 2.8. In all cases, we find that the Universe is ionized at less than the 10% level at redshifts above z = 10. This suggests that an early onset of reionization is strongly disfavoured by the Planck data. We show that this result also reduces the tension between CMB-based analyses and constraints from other astrophysical sources.
Planck 2018 results Aghanim, N.; Akrami, Y.; Aumont, J. ...
Astronomy and astrophysics (Berlin),
09/2020, Letnik:
641
Journal Article
Recenzirano
Odprti dostop
This paper presents the High Frequency Instrument (HFI) data processing procedures for the
Planck
2018 release. Major improvements in mapmaking have been achieved since the previous
Planck
2015 ...release, many of which were used and described already in an intermediate paper dedicated to the
Planck
polarized data at low multipoles. These improvements enabled the first significant measurement of the reionization optical depth parameter using
Planck
-HFI data. This paper presents an extensive analysis of systematic effects, including the use of end-to-end simulations to facilitate their removal and characterize the residuals. The polarized data, which presented a number of known problems in the 2015
Planck
release, are very significantly improved, especially the leakage from intensity to polarization. Calibration, based on the cosmic microwave background (CMB) dipole, is now extremely accurate and in the frequency range 100–353 GHz reduces intensity-to-polarization leakage caused by calibration mismatch. The Solar dipole direction has been determined in the three lowest HFI frequency channels to within one arc minute, and its amplitude has an absolute uncertainty smaller than 0.35
μ
K, an accuracy of order 10
−4
. This is a major legacy from the
Planck
HFI for future CMB experiments. The removal of bandpass leakage has been improved for the main high-frequency foregrounds by extracting the bandpass-mismatch coefficients for each detector as part of the mapmaking process; these values in turn improve the intensity maps. This is a major change in the philosophy of “frequency maps”, which are now computed from single detector data, all adjusted to the same average bandpass response for the main foregrounds. End-to-end simulations have been shown to reproduce very well the relative gain calibration of detectors, as well as drifts within a frequency induced by the residuals of the main systematic effect (analogue-to-digital convertor non-linearity residuals). Using these simulations, we have been able to measure and correct the small frequency calibration bias induced by this systematic effect at the 10
−4
level. There is no detectable sign of a residual calibration bias between the first and second acoustic peaks in the CMB channels, at the 10
−3
level.
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.
PDF
