BEYONDPLANCK

XII. Cosmological parameter constraints with end-to-end error propagation

¹ Dipartimento di Fisica, Università degli Studi di Milano, Via Celoria, 16, Milano, Italy
e-mail: simone.paradiso@unimi.it
² INFN, Sezione di Milano, Via Celoria 16, Milano, Italy
³ Institute of Theoretical Astrophysics, University of Oslo, Blindern, Oslo, Norway
⁴ INAF-IASF Milano, Via E. Bassini 15, Milano, Italy
⁵ INAF – Osservatorio Astronomico di Trieste, Via G.B. Tiepolo 11, Trieste, Italy
⁶ Planetek Hellas, Leoforos Kifisias 44, Marousi, 151 25 Greece
⁷ Department of Astrophysical Sciences, Princeton University, Princeton, NJ, 08544 USA
⁸ Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA, USA
⁹ Department of Physics, Gustaf Hällströmin katu 2, University of Helsinki, Helsinki, Finland
¹⁰ Helsinki Institute of Physics, Gustaf Hällströmin katu 2, University of Helsinki, Helsinki, Finland
¹¹ Computational Cosmology Center, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
¹² Haverford College Astronomy Department, 370 Lancaster Avenue, Haverford, Pennsylvania, USA
¹³ Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching, Germany
¹⁴ Dipartimento di Fisica, Università degli Studi di Trieste, Via A. Valerio 2, Trieste, Italy

Received: 20 May 2022
Accepted: 20 September 2022

Abstract

We present cosmological parameter constraints estimated using the Bayesian BEYONDPLANCK 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 1σ when considering only temperature multipoles between 30 ≤ ℓ ≤ 600. In cases where there are differences, we note that the BEYONDPLANCK 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 BEYONDPLANCK 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.