21. 
 Aghanim, N., et al.
(författare)

Planck intermediate results XLIV. Structure of the Galactic magnetic field from dust polarization maps of the southern Galactic cap
 2016

Ingår i: Astronomy and Astrophysics.  : EDP Sciences.  00046361 . 14320746. ; 596

Tidskriftsartikel (refereegranskat)abstract
 Using data from the Planck satellite, we study the statistical properties of interstellar dust polarization at high Galactic latitudes around the south pole (b < 60 degrees). Our aim is to advance the understanding of the magnetized interstellar medium (ISM), and to provide a modelling framework of the polarized dust foreground for use in cosmic microwave background (CMB) componentseparation procedures. We examine the Stokes I, Q, and U maps at 353 GHz, and particularly the statistical distribution of the polarization fraction (p) and angle (Psi), in order to characterize the ordered and turbulent components of the Galactic magnetic field (GMF) in the solar neighbourhood. The Q and U maps show patterns at large angular scales, which we relate to the mean orientation of the GMF towards Galactic coordinates (l(0); b(0)) = (70 degrees +/ 5 degrees, 24 degrees +/ 5 degrees). The histogram of the observed p values shows a wide dispersion up to 25%. The histogram Psi of has a standard deviation of 12 degrees about the regular pattern expected from the ordered GMF. We build a phenomenological model that connects the distributions of p and Psi to a statistical description of the turbulent component of the GMF, assuming a uniform effective polarization fraction (p(0)) of dust emission. To compute the Stokes parameters, we approximate the integration along the line of sight (LOS) as a sum over a set of N independent polarization layers, in each of which the turbulent component of the GMF is obtained from Gaussian realizations of a powerlaw power spectrum. We are able to reproduce the observed p and distributions using a p0 value of 26%, a ratio of 0.9 between the strengths of the turbulent and mean components of the GMF, and a small value of N. The mean value of p (inferred from the fit of the largescale patterns in the Stokes maps) is 12 +/ 1%. We relate the polarization layers to the density structure and to the correlation length of the GMF along the LOS. We emphasize the simplicity of our model (involving only a few parameters), which can be easily computed on the celestial sphere to produce simulated maps of dust polarization. Our work is an important step towards a model that can be used to assess the accuracy of componentseparation methods in present and future CMB experiments designed to search the B mode CMB polarization from primordial gravity waves.


22. 
 Aghanim, N., et al.
(författare)

Planck intermediate results XLVI. Reduction of largescale systematic effects in HFI polarization maps and estimation of the reionization optical depth
 2016

Ingår i: Astronomy and Astrophysics.  : EDP Sciences.  00046361 . 14320746. ; 596

Tidskriftsartikel (refereegranskat)abstract
 This paper describes the identification, modelling, and removal of previously unexplained systematic effects in the polarization data of the Planck High Frequency Instrument (HFI) on large angular scales, including new mapmaking and calibration procedures, new and more complete endtoend simulations, and a set of robust internal consistency checks on the resulting maps. These maps, at 100, 143, 217, and 353 GHz, are early versions of those that will be released in final form later in 2016. The improvements allow us to determine the cosmic reionization optical depth tau using, for the first time, the lowmultipole EE data from HFI, reducing significantly the central value and uncertainty, and hence the upper limit. Two different likelihood procedures are used to constrain tau from two estimators of the CMB E and Bmode angular power spectra at 100 and 143 GHz, after debiasing the spectra from a small remaining systematic contamination. These all give fully consistent results. A further consistency test is performed using crosscorrelations derived from the Low Frequency Instrument maps of the Planck 2015 data release and the new HFI data. For this purpose, endtoend analyses of systematic effects from the two instruments are used to demonstrate the near independence of their dominant systematic error residuals. The tightest result comes from the HFIbased tau posterior distribution using the maximum likelihood power spectrum estimator from EE data only, giving a value 0.055 +/ 0.009. In a companion paper these results are discussed in the context of the bestfit Planck Lambda CDM cosmological model and recent models of reionization.


23. 
 Akrami, Y., et al.
(författare)

Planck 2018 results X. Constraints on inflation
 2020

Ingår i: Astronomy and Astrophysics.  : EDP Sciences.  00046361 . 14320746. ; 641

Tidskriftsartikel (refereegranskat)abstract
 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 tensortoscalar 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 singlefield inflationary models with Einstein gravity, these results imply that: (a) the predictions of slowroll models with a concave potential, V(phi) < 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 nonparametric reconstruction of the primordial power spectrum consistently confirm a pure power law in the range of comoving scales 0.005 Mpc(1)k less than or similar to 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 nonadiabatic 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 matterbaryon 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 scaledependent dipolar modulation. All these findings support the key predictions of the standard singlefield inflationary models, which will be further tested by future cosmological observations.


24. 
 Adam, R., et al.
(författare)

Planck intermediate results XLVII. Planck constraints on reionization history
 2016

Ingår i: Astronomy and Astrophysics.  : EDP Sciences.  00046361 . 14320746. ; 596

Tidskriftsartikel (refereegranskat)abstract
 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 lowmultipole polarization data to fit Lambda CDM models with various parameterizations of the reionization history. We obtain a Thomson optical depth tau = 0.058 +/ 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 SunyaevZeldovich (kSZ) effect using additional information from the highresolution 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 redshiftsymmetric reionization model, we find an upper limit to the width of the reionization period of Delta z < 2.8. In all cases, we find that the Universe is ionized at less than the 10% level at redshifts above z similar or equal to 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 CMBbased analyses and constraints from other astrophysical sources.


25. 
 Aghanim, N., et al.
(författare)

Planck 2018 results VIII. Gravitational lensing
 2020

Ingår i: Astronomy and Astrophysics.  : EDP Sciences.  00046361 . 14320746. ; 641

Tidskriftsartikel (refereegranskat)abstract
 We present measurements of the cosmic microwave background (CMB) lensing potential using the final Planck 2018 temperature and polarization data. Using polarization maps filtered to account for the noise anisotropy, we increase the significance of the detection of lensing in the polarization maps from 5 sigma to 9 sigma. Combined with temperature, lensing is detected at 40 sigma. We present an extensive set of tests of the robustness of the lensingpotential power spectrum, and construct a minimumvariance estimator likelihood over lensing multipoles 8 <= L <= 400 (extending the range to lower L compared to 2015), which we use to constrain cosmological parameters. We find good consistency between lensing constraints and the results from the Planck CMB power spectra within the Lambda CDM model. Combined with baryon density and other weak priors, the lensing analysis alone constrains (8)Omega (0.25)(m) = 0.589 +/ 0.020 sigma 8 Omega m 0.25 = 0.589 +/ 0.020 (1 sigma errors). Also combining with baryon acoustic oscillation data, we find tight individual parameter constraints, sigma (8)=0.811 +/ 0.019, H0 = 67.9(1.3)(+1.2) km s(1) Mpc(1) H 0 = 67 . 9  1.3 + 1.2 .> km s  1 . Mpc  1 , and Omega (m) = 0.303(0.018)(+0.016) Omega m = 0 . 303  0.018 + 0.016 . Combining with Planck CMB power spectrum data, we measure sigma (8) to better than 1% precision, finding sigma (8)=0.811 +/ 0.006. CMB lensing reconstruction data are complementary to galaxy lensing data at lower redshift, having a different degeneracy direction in sigma (8)Omega (m) space; we find consistency with the lensing results from the Dark Energy Survey, and give combined lensingonly parameter constraints that are tighter than joint results using galaxy clustering. Using the Planck cosmic infrared background (CIB) maps as an additional tracer of highredshift matter, we make a combined Planckonly estimate of the lensing potential over 60% of the sky with considerably more smallscale signal. We additionally demonstrate delensing of the Planck power spectra using the joint and individual lensing potential estimates, detecting a maximum removal of 40% of the lensinginduced power in all spectra. The improvement in the sharpening of the acoustic peaks by including both CIB and the quadratic lensing reconstruction is detected at high significance.


26. 
 Aghanim, N., et al.
(författare)

Planck intermediate results L. Evidence of spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB Bmode analysis
 2017

Ingår i: Astronomy and Astrophysics.  : EDP Sciences.  00046361 . 14320746. ; 599

Tidskriftsartikel (refereegranskat)abstract
 The characterization of the Galactic foregrounds has been shown to be the main obstacle in the challenging quest to detect primordial Bmodes in the polarized microwave sky. We make use of the PlanckHFI 2015 data release at high frequencies to place new constraints on the properties of the polarized thermal dust emission at high Galactic latitudes. Here, we specifically study the spatial variability of the dust polarized spectral energy distribution (SED), and its potential impact on the determination of the tensortoscalar ratio, r. We use the correlation ratio of the CBB `angular power spectra between the 217 and 353 GHz channels as a tracer of these potential variations, computed on different high Galactic latitude regions, ranging from 80% to 20% of the sky. The new insight from Planck data is a departure of the correlation ratio from unity that cannot be attributed to a spurious decorrelation due to the cosmic microwave background, instrumental noise, or instrumental systematics. The effect is marginally detected on each region, but the statistical combination of all the regions gives more than 99% confidence for this variation in polarized dust properties. In addition, we show that the decorrelation increases when there is a decrease in the mean column density of the region of the sky being considered, and we propose a simple powerlaw empirical model for this dependence, which matches what is seen in the Planck data. We explore the effect that this measured decorrelation has on simulations of the BICEP2Keck Array/Planck analysis and show that the 2015 constraints from these data still allow a decorrelation between the dust at 150 and 353 GHz that is compatible with our measured value. Finally, using simplified models, we show that either spatial variation of the dust SED or of the dust polarization angle are able to produce decorrelations between 217 and 353 GHz data similar to the values we observe in the data.


27. 
 Aghanim, N., et al.
(författare)

Planck intermediate results LI. Features in the cosmic microwave background temperature power spectrum and shifts in cosmological parameters
 2017

Ingår i: Astronomy and Astrophysics.  : EDP Sciences.  00046361 . 14320746. ; 607

Tidskriftsartikel (refereegranskat)abstract
 The six parameters of the standard Lambda CDM model have bestfit values derived from the Planck temperature power spectrum that are shifted somewhat from the bestfit values derived from WMAP data. These shifts are driven by features in the Planck temperature power spectrum at angular scales that had never before been measured to cosmicvariance level precision. We have investigated these shifts to determine whether they are within the range of expectation and to understand their origin in the data. Taking our parameter set to be the optical depth of the reionized intergalactic medium tau, the baryon density omega(b), the matter density omega(m), the angular size of the sound horizon theta(*), the spectral index of the primordial power spectrum, n(s), and A(s)e(2 pi) (where As is the amplitude of the primordial power spectrum), we have examined the change in bestfit values between a WMAPlike large angularscale data set (with multipole moment l < 800 in the Planck temperature power spectrum) and an all angularscale data set (l < 2500 Planck temperature power spectrum), each with a prior on tau of 0.07 +/ 0.02. We find that the shifts, in units of the 1 sigma expected dispersion for each parameter, are {Delta tau, Delta A(s)e(2 tau), Delta n(s), Delta omega(m), Delta omega(b), Delta theta(*)} = {1.7, 2.2, 1.2, 2.0, 1.1, 0.9}, with a chi(2) value of 8.0. We find that this chi(2) value is exceeded in 15% of our simulated data sets, and that a parameter deviates by more than 2.2 sigma in 9% of simulated data sets, meaning that the shifts are not unusually large. Comparing l < 800 instead to l > 800, or splitting at a different multipole, yields similar results. We examined the l < 800 model residuals in the l > 800 power spectrum data and find that the features there that drive these shifts are a set of oscillations across a broad range of angular scales. Although they partly appear similar to the effects of enhanced gravitational lensing, the shifts in Lambda CDM parameters that arise in response to these features correspond to model spectrum changes that are predominantly due to nonlensing effects; the only exception is tau, which, at fixed A(s)e(2 tau), affects the l > 800 temperature power spectrum solely through the associated change in As and the impact of that on the lensing potential power spectrum. We also ask, what is it about the power spectrum at l < 800 that leads to somewhat different bestfit parameters than come from the full l range? We find that if we discard the data at l < 30, where there is a roughly 2 sigma downward fluctuation in power relative to the model that best fits the full l range, the l < 800 bestfit parameters shift significantly towards the l < 2500 bestfit parameters. In contrast, including l < 30, this previously noted lowl deficit drives ns up and impacts parameters correlated with ns, such as omega(m) and H0. As expected, the l < 30 data have a much greater impact on the l < 800 best fit than on the l < 2500 best fit. So although the shifts are not very significant, we find that they can be understood through the combined effects of an oscillatorylike set of highl residuals and the deficit in lowl power, excursions consistent with sample variance that happen to map onto changes in cosmological parameters. Finally, we examine agreement between Planck TT data and two other CMB data sets, namely the Planck lensing reconstruction and the TT power spectrum measured by the South Pole Telescope, again finding a lack of convincing evidence of any significant deviations in parameters, suggesting that current CMB data sets give an internally consistent picture of the Lambda CDM model.


28. 
 Sugai, H., et al.
(författare)

Updated Design of the CMB Polarization Experiment Satellite LiteBIRD
 2020

Ingår i: Journal of Low Temperature Physics.  : Springer Science and Business Media LLC.  00222291 . 15737357. ; 199:34, s. 11071117

Tidskriftsartikel (refereegranskat)abstract
 Recent developments of transitionedge sensors (TESs), based on extensive experience in groundbased experiments, have been making the sensor techniques mature enough for their application on future satellite cosmic microwave background (CMB) polarization experiments. LiteBIRD is in the most advanced phase among such future satellites, targeting its launch in Japanese Fiscal Year 2027 (2027FY) with JAXA's H3 rocket. It will accommodate more than 4000 TESs in focal planes of reflective lowfrequency and refractive mediumandhighfrequency telescopes in order to detect a signature imprinted on the CMB by the primordial gravitational waves predicted in cosmic inflation. The total wide frequency coverage between 34 and 448 GHz enables us to extract such weak spiral polarization patterns through the precise subtraction of our Galaxy's foreground emission by using spectral differences among CMB and foreground signals. Telescopes are cooled down to 5 K for suppressing thermal noise and contain polarization modulators with transmissive halfwave plates at individual apertures for separating sky polarization signals from artificial polarization and for mitigating from instrumental 1/f noise. Passive cooling by using Vgrooves supports active cooling with mechanical coolers as well as adiabatic demagnetization refrigerators. Sky observations from the second SunEarth Lagrangian point, L2, are planned for 3 years. An international collaboration between Japan, the USA, Canada, and Europe is sharing various roles. In May 2019, the Institute of Space and Astronautical Science, JAXA, selected LiteBIRD as the strategic large mission No. 2.


29. 
 Aghanim, N., et al.
(författare)

Planck 2018 results XII. Galactic astrophysics using polarized dust emission
 2020

Ingår i: Astronomy and Astrophysics.  : EDP Sciences.  00046361 . 14320746. ; 641

Tidskriftsartikel (refereegranskat)abstract
 Observations of the submillimetre emission from Galactic dust, in both total intensity I and polarization, have received tremendous interest thanks to the Planck fullsky maps. In this paper we make use of such fullsky maps of dust polarized emission produced from the third public release of Planck data. As the basis for expanding on astrophysical studies of the polarized thermal emission from Galactic dust, we present fullsky maps of the dust polarization fraction p, polarization angle psi, and dispersion function of polarization angles ?. The joint distribution (onepoint statistics) of p and NH confirms that the mean and maximum polarization fractions decrease with increasing NH. The uncertainty on the maximum observed polarization fraction, (max) = 22.0(1.4)(+3.5) p max = 22 . 0  1.4 + 3.5 % at 353 GHz and 80 ' resolution, is dominated by the uncertainty on the Galactic emission zero level in total intensity, in particular towards diffuse lines of sight at high Galactic latitudes. Furthermore, the inverse behaviour between p and ? found earlier is seen to be present at high latitudes. This follows the ?proportional to p(1) relationship expected from models of the polarized sky (including numerical simulations of magnetohydrodynamical turbulence) that include effects from only the topology of the turbulent magnetic field, but otherwise have uniform alignment and dust properties. Thus, the statistical properties of p, psi, and ? for the most part reflect the structure of the Galactic magnetic field. Nevertheless, we search for potential signatures of varying grain alignment and dust properties. First, we analyse the product map ?xp, looking for residual trends. While the polarization fraction p decreases by a factor of 34 between NH=10(20) cm(2) and NH=2x10(22) cm(2), out of the Galactic plane, this product ?xp only decreases by about 25%. Because ? is independent of the grain alignment efficiency, this demonstrates that the systematic decrease in p with NH is determined mostly by the magneticfield structure and not by a drop in grain alignment. This systematic trend is observed both in the diffuse interstellar medium (ISM) and in molecular clouds of the Gould Belt. Second, we look for a dependence of polarization properties on the dust temperature, as we would expect from the radiative alignment torque (RAT) theory. We find no systematic trend of ?xp with the dust temperature Td, whether in the diffuse ISM or in the molecular clouds of the Gould Belt. In the diffuse ISM, lines of sight with high polarization fraction p and low polarization angle dispersion ? tend, on the contrary, to have colder dust than lines of sight with low p and high ?. We also compare the Planck thermal dust polarization with starlight polarization data in the visible at high Galactic latitudes. The agreement in polarization angles is remarkable, and is consistent with what we expect from the noise and the observed dispersion of polarization angles in the visible on the scale of the Planck beam. The two polarization emissiontoextinction ratios, RP/p and RS/V, which primarily characterize dust optical properties, have only a weak dependence on the column density, and converge towards the values previously determined for translucent lines of sight. We also determine an upper limit for the polarization fraction in extinction, p(V)/E(BV), of 13% at high Galactic latitude, compatible with the polarization fraction p approximate to 20% observed at 353 GHz. Taken together, these results provide strong constraints for models of Galactic dust in diffuse gas.


30. 
 Akrami, Y., et al.
(författare)

Planck 2018 results IX. Constraints on primordial nonGaussianity
 2020

Ingår i: Astronomy and Astrophysics.  : EDP Sciences.  00046361 . 14320746. ; 641

Tidskriftsartikel (refereegranskat)abstract
 We analyse the Planck fullmission cosmic microwave background (CMB) temperature and Emode polarization maps to obtain constraints on primordial nonGaussianity (NG). We compare estimates obtained from separable templatefitting, binned, and optimal modal bispectrum estimators, finding consistent values for the local, equilateral, and orthogonal bispectrum amplitudes. Our combined temperature and polarization analysis produces the following final results: (local)(NL) = 0.9 +/ 5.1 f NL local =  0.9 +/ 5.1 ; f(NL)(equil) = 26 +/ 47 f NL equil =  26 +/ 47 ; and f(NL)(ortho) = 38 +/ 24 f NL ortho =  38 +/ 24 (68% CL, statistical). These results include lowmultipole (4 <= l< 40) polarization data that are not included in our previous analysis. The results also pass an extensive battery of tests (with additional tests regarding foreground residuals compared to 2015), and they are stable with respect to our 2015 measurements (with small fluctuations, at the level of a fraction of a standard deviation, which is consistent with changes in data processing). Polarizationonly bispectra display a significant improvement in robustness; they can now be used independently to set primordial NG constraints with a sensitivity comparable to WMAP temperaturebased results and they give excellent agreement. In addition to the analysis of the standard local, equilateral, and orthogonal bispectrum shapes, we consider a large number of additional cases, such as scaledependent feature and resonance bispectra, isocurvature primordial NG, and paritybreaking models, where we also place tight constraints but do not detect any signal. The nonprimordial lensing bispectrum is, however, detected with an improved significance compared to 2015, excluding the null hypothesis at 3.5. Beyond estimates of individual shape amplitudes, we also present modelindependent reconstructions and analyses of the Planck CMB bispectrum. Our final constraint on the local primordial trispectrum shape is g(NL)(local) = (5.8 +/ 6.5) x 10(4) g NL local = (  5.8 +/ 6.5 ) x 10 4 (68% CL, statistical), while constraints for other trispectrum shapes are also determined. Exploiting the tight limits on various bispectrum and trispectrum shapes, we constrain the parameter space of different earlyUniverse scenarios that generate primordial NG, including general singlefield models of inflation, multifield models (e.g. curvaton models), models of inflation with axion fields producing parityviolation bispectra in the tensor sector, and inflationary models involving vectorlike fields with directionallydependent bispectra. Our results provide a highprecision test for structureformation scenarios, showing complete agreement with the basic picture of the Lambda CDM cosmology regarding the statistics of the initial conditions, with cosmic structures arising from adiabatic, passive, Gaussian, and primordial seed perturbations.

