39 research outputs found
Cosmological parameters derived from the final (PR4) Planck data release
International audienceWe present constraints on cosmological parameters using maps from the last Planck data release (PR4). In particular, we detail an upgraded version of the cosmic microwave background likelihood, HiLLiPoP, based on angular power spectra and relying on a physical modelling 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 derive constraints on CDM parameters that are in good agreement with previous Planck 2018 results, but with 10% to 20% smaller uncertainties. We demonstrate that the foregrounds can be accurately described in spectra domain with only negligible impact on CDM parameters. We also derive constraints on single-parameter extensions to CDM including , , , and . Noteworthy results from this updated analysis include a lensing amplitude value of , which aligns more closely with theoretical expectations within the CDM framework. Additionally, our curvature measurement, , now demonstrates complete consistency with a flat universe, and our measurement of is closer to the measurements derived from large-scale structure surveys (at the 1.6 level)
Cosmoglobe: Towards end-to-end CMB cosmological parameter estimation without likelihood approximations
Cosmoglobe DR1 results. II. Constraints on isotropic cosmic birefringence from reprocessed WMAP and Planck LFI data
International audienceCosmic birefringence is a parity-violating effect that might have rotated the plane of linearly polarized light of the cosmic microwave background (CMB) by an angle since its emission. This has recently been measured to be non-zero at a statistical significance of in the official Planck PR4 and 9-year WMAP data. In this work, we constrain using the reprocessed BeyondPlanck LFI and Cosmoglobe DR1 WMAP polarization maps. These novel maps have both lower systematic residuals and a more complete error description than the corresponding official products. Foreground correlations could bias measurements of , and while thermal dust emission has been argued to be statistically non-zero, no evidence for synchrotron power has been reported. Unlike the dust-dominated Planck HFI maps, the majority of the LFI and WMAP polarization maps are instead dominated by synchrotron emission. Simultaneously constraining and the polarization miscalibration angle, , of each channel, we find a best-fit value of with LFI and WMAP data only. When including the Planck HFI PR4 maps, but fitting separately for dust-dominated, , and synchrotron-dominated channels, , we find . This differs from zero with a statistical significance of , and the main contribution to this value comes from the LFI 70 GHz channel. While the statistical significances of these results are low on their own, the measurement derived from the LFI and WMAP synchrotron-dominated maps agrees with the previously reported HFI-dominated constraints, despite the very different astrophysical and instrumental systematics involved in all these experiments
Cosmoglobe DR1 results. II. Constraints on isotropic cosmic birefringence from reprocessed WMAP and Planck LFI data
International audienceCosmic birefringence is a parity-violating effect that might have rotated the plane of linearly polarized light of the cosmic microwave background (CMB) by an angle since its emission. This has recently been measured to be non-zero at a statistical significance of in the official Planck PR4 and 9-year WMAP data. In this work, we constrain using the reprocessed BeyondPlanck LFI and Cosmoglobe DR1 WMAP polarization maps. These novel maps have both lower systematic residuals and a more complete error description than the corresponding official products. Foreground correlations could bias measurements of , and while thermal dust emission has been argued to be statistically non-zero, no evidence for synchrotron power has been reported. Unlike the dust-dominated Planck HFI maps, the majority of the LFI and WMAP polarization maps are instead dominated by synchrotron emission. Simultaneously constraining and the polarization miscalibration angle, , of each channel, we find a best-fit value of with LFI and WMAP data only. When including the Planck HFI PR4 maps, but fitting separately for dust-dominated, , and synchrotron-dominated channels, , we find . This differs from zero with a statistical significance of , and the main contribution to this value comes from the LFI 70 GHz channel. While the statistical significances of these results are low on their own, the measurement derived from the LFI and WMAP synchrotron-dominated maps agrees with the previously reported HFI-dominated constraints, despite the very different astrophysical and instrumental systematics involved in all these experiments
Cosmoglobe DR1 results. II. Constraints on isotropic cosmic birefringence from reprocessed WMAP and Planck LFI data
International audienceCosmic birefringence is a parity-violating effect that might have rotated the plane of linearly polarized light of the cosmic microwave background (CMB) by an angle since its emission. This has recently been measured to be non-zero at a statistical significance of in the official Planck PR4 and 9-year WMAP data. In this work, we constrain using the reprocessed BeyondPlanck LFI and Cosmoglobe DR1 WMAP polarization maps. These novel maps have both lower systematic residuals and a more complete error description than the corresponding official products. Foreground correlations could bias measurements of , and while thermal dust emission has been argued to be statistically non-zero, no evidence for synchrotron power has been reported. Unlike the dust-dominated Planck HFI maps, the majority of the LFI and WMAP polarization maps are instead dominated by synchrotron emission. Simultaneously constraining and the polarization miscalibration angle, , of each channel, we find a best-fit value of with LFI and WMAP data only. When including the Planck HFI PR4 maps, but fitting separately for dust-dominated, , and synchrotron-dominated channels, , we find . This differs from zero with a statistical significance of , and the main contribution to this value comes from the LFI 70 GHz channel. While the statistical significances of these results are low on their own, the measurement derived from the LFI and WMAP synchrotron-dominated maps agrees with the previously reported HFI-dominated constraints, despite the very different astrophysical and instrumental systematics involved in all these experiments
LiteBIRD Science Goals and Forecasts: Primordial Magnetic Fields
International audienceWe present detailed forecasts for the constraints on primordial magnetic fields (PMFs) that will be obtained with the LiteBIRD satellite. The constraints are driven by the effects of PMFs on the CMB anisotropies: the gravitational effects of magnetically-induced perturbations; the effects on the thermal and ionization history of the Universe; the Faraday rotation imprint on the CMB polarization; and the non-Gaussianities induced in polarization anisotropies. LiteBIRD represents a sensitive probe for PMFs and by exploiting all the physical effects, it will be able to improve the current limit coming from Planck. In particular, thanks to its accurate -mode polarization measurement, LiteBIRD will improve the constraints on infrared configurations for the gravitational effect, giving nG at 95% C.L., potentially opening the possibility to detect nanogauss fields with high significance. We also observe a significant improvement in the limits when marginalized over the spectral index, nG at 95% C.L. From the thermal history effect, which relies mainly on -mode polarization data, we obtain a significant improvement for all PMF configurations, with the marginalized case, nG at 95% C.L. Faraday rotation constraints will take advantage of the wide frequency coverage of LiteBIRD and the high sensitivity in modes, improving the limits by orders of magnitude with respect to current results, nG at 95% C.L. Finally, non-Gaussianities of the -mode polarization can probe PMFs at the level of 1 nG, again significantly improving the current bounds from Planck. Altogether our forecasts represent a broad collection of complementary probes, providing conservative limits on PMF characteristics that will be achieved with LiteBIRD
LiteBIRD Science Goals and Forecasts: Primordial Magnetic Fields
International audienceWe present detailed forecasts for the constraints on primordial magnetic fields (PMFs) that will be obtained with the LiteBIRD satellite. The constraints are driven by the effects of PMFs on the CMB anisotropies: the gravitational effects of magnetically-induced perturbations; the effects on the thermal and ionization history of the Universe; the Faraday rotation imprint on the CMB polarization; and the non-Gaussianities induced in polarization anisotropies. LiteBIRD represents a sensitive probe for PMFs and by exploiting all the physical effects, it will be able to improve the current limit coming from Planck. In particular, thanks to its accurate -mode polarization measurement, LiteBIRD will improve the constraints on infrared configurations for the gravitational effect, giving nG at 95% C.L., potentially opening the possibility to detect nanogauss fields with high significance. We also observe a significant improvement in the limits when marginalized over the spectral index, nG at 95% C.L. From the thermal history effect, which relies mainly on -mode polarization data, we obtain a significant improvement for all PMF configurations, with the marginalized case, nG at 95% C.L. Faraday rotation constraints will take advantage of the wide frequency coverage of LiteBIRD and the high sensitivity in modes, improving the limits by orders of magnitude with respect to current results, nG at 95% C.L. Finally, non-Gaussianities of the -mode polarization can probe PMFs at the level of 1 nG, again significantly improving the current bounds from Planck. Altogether our forecasts represent a broad collection of complementary probes, providing conservative limits on PMF characteristics that will be achieved with LiteBIRD
LiteBIRD Science Goals and Forecasts: Primordial Magnetic Fields
International audienceWe present detailed forecasts for the constraints on primordial magnetic fields (PMFs) that will be obtained with the LiteBIRD satellite. The constraints are driven by the effects of PMFs on the CMB anisotropies: the gravitational effects of magnetically-induced perturbations; the effects on the thermal and ionization history of the Universe; the Faraday rotation imprint on the CMB polarization; and the non-Gaussianities induced in polarization anisotropies. LiteBIRD represents a sensitive probe for PMFs and by exploiting all the physical effects, it will be able to improve the current limit coming from Planck. In particular, thanks to its accurate -mode polarization measurement, LiteBIRD will improve the constraints on infrared configurations for the gravitational effect, giving nG at 95% C.L., potentially opening the possibility to detect nanogauss fields with high significance. We also observe a significant improvement in the limits when marginalized over the spectral index, nG at 95% C.L. From the thermal history effect, which relies mainly on -mode polarization data, we obtain a significant improvement for all PMF configurations, with the marginalized case, nG at 95% C.L. Faraday rotation constraints will take advantage of the wide frequency coverage of LiteBIRD and the high sensitivity in modes, improving the limits by orders of magnitude with respect to current results, nG at 95% C.L. Finally, non-Gaussianities of the -mode polarization can probe PMFs at the level of 1 nG, again significantly improving the current bounds from Planck. Altogether our forecasts represent a broad collection of complementary probes, providing conservative limits on PMF characteristics that will be achieved with LiteBIRD
Tensor-to-scalar ratio forecasts for extended LiteBIRD frequency configurations
International audienceLiteBIRD is a planned JAXA-led 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, , down to . 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 SED, and a relatively minor high frequency extension can therefore result in even lower uncertainties and better model reconstructions. Specifically, we compare the baseline design with five extended configurations, while varying the underlying dust modeling, in each of which the HFT (High-Frequency Telescope) frequency range is shifted logarithmically towards higher frequencies, with an upper cutoff ranging between 400 and 600 GHz. In each case, we measure the tensor-to-scalar ratio 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 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 better ability to discriminate between models through higher sensitivity. (abridged
Impact of beam far side-lobe knowledge in the presence of foregrounds for LiteBIRD
International audienceWe present a study of the impact of an uncertainty in the beam far side-lobe knowledge on the measurement of the Cosmic Microwave Background -mode signal at large scale. It is expected to be one of the main source of systematic effects in future CMB observations. Because it is crucial for all-sky survey missions to take into account the interplays between beam systematic effects and all the data analysis steps, the primary goal of this paper is to provide the methodology to carry out the end-to-end study of their effect for a space-borne CMB polarization experiment, up to the cosmological results in the form of a bias on the tensor-to-scalar ratio . LiteBIRD is dedicated to target the measurement of CMB primordial modes by reaching a sensitivity of assuming . As a demonstration of our framework, we derive the relationship between the knowledge of the beam far side-lobes and the tentatively allocated error budget under given assumptions on design, simulation and component separation method. We assume no mitigation of the far side-lobes effect at any stage of the analysis pipeline. We show that is mostly due to the integrated fractional power difference between the estimated beams and the true beams in the far side-lobes region, with little dependence on the actual shape of the beams, for low enough . Under our set of assumptions, in particular considering the specific foreground cleaning method we used, we find that the integrated fractional power in the far side-lobes should be known at a level as tight as , to achieve the required limit on the bias . The framework and tools developed for this study can be easily adapted to provide requirements under different design, data analysis frameworks and for other future space-borne experiments beyond LiteBIRD