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  1. Article ; Online: Cosmic Birefringence from the Planck Data Release 4.

    Diego-Palazuelos, P / Eskilt, J R / Minami, Y / Tristram, M / Sullivan, R M / Banday, A J / Barreiro, R B / Eriksen, H K / Górski, K M / Keskitalo, R / Komatsu, E / Martínez-González, E / Scott, D / Vielva, P / Wehus, I K

    Physical review letters

    2022  Volume 128, Issue 9, Page(s) 91302

    Abstract: 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 ... ...

    Abstract 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.
    Language English
    Publishing date 2022-03-18
    Publishing country United States
    Document type Journal Article
    ZDB-ID 208853-8
    ISSN 1079-7114 ; 0031-9007
    ISSN (online) 1079-7114
    ISSN 0031-9007
    DOI 10.1103/PhysRevLett.128.091302
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Book ; Online: BeyondPlanck IV. On end-to-end simulations in CMB analysis -- Bayesian versus frequentist statistics

    Brilenkov, M. / Fornazier, K. S. F. / Hergt, L. T. / Hoerning, G. A. / Marins, A. / Murokoshi, T. / Rahman, F. / Stutzer, N. -O. / Zhou, Y. / Abdalla, F. B. / Andersen, K. J. / Aurlien, R. / Banerji, R. / Basyrov, A. / Battista, A. / Bersanelli, M. / Bertocco, S. / Bollanos, S. / Colombo, L. P. L. /
    Eriksen, H. K. / Eskilt, J. R. / Foss, M. K. / Franceschet, C. / Fuskeland, U. / Galeotta, S. / Galloway, M. / Gerakakis, S. / Gjerlow, E. / Hensley, B. / Herman, D. / Hoang, T. D. / Ieronymaki, M. / Ihle, H. T. / Jewell, J. B. / Karakci, A. / Keihanen, E. / Keskitalo, R. / Maggio, G. / Maino, D. / Maris, M. / Paradiso, S. / Partridge, B. / Reinecke, M. / Suur-Uski, A. -S. / Svalheim, T. L. / Tavagnacco, D. / Thommesen, H. / Tomasi, M. / Watts, D. J. / Wehus, I. K. / Zacchei, A.

    2022  

    Abstract: End-to-end simulations play a key role in the analysis of any high-sensitivity CMB experiment, providing high-fidelity systematic error propagation capabilities unmatched by any other means. In this paper, we address an important issue regarding such ... ...

    Abstract End-to-end simulations play a key role in the analysis of any high-sensitivity CMB experiment, providing high-fidelity systematic error propagation capabilities unmatched by any other means. In this paper, we address an important issue regarding such simulations, namely how to define the inputs in terms of sky model and instrument parameters. These may either be taken as a constrained realization derived from the data, or as a random realization independent from the data. We refer to these as Bayesian and frequentist simulations, respectively. We show that the two options lead to significantly different correlation structures, as frequentist simulations, contrary to Bayesian simulations, effectively include cosmic variance, but exclude realization-specific correlations from non-linear degeneracies. Consequently, they quantify fundamentally different types of uncertainties, and we argue that they therefore also have different and complementary scientific uses, even if this dichotomy is not absolute. Before BeyondPlanck, most pipelines have used a mix of constrained and random inputs, and used the same hybrid simulations for all applications, even though the statistical justification for this is not always evident. BeyondPlanck represents the first end-to-end CMB simulation framework that is able to generate both types of simulations, and these new capabilities have brought this topic to the forefront. The Bayesian BeyondPlanck simulations and their uses are described extensively in a suite of companion papers. In this paper we consider one important applications of the corresponding frequentist simulations, namely code validation. That is, we generate a set of 1-year LFI 30 GHz frequentist simulations with known inputs, and use these to validate the core low-level BeyondPlanck algorithms; gain estimation, correlated noise estimation, and mapmaking.
    Keywords Astrophysics - Cosmology and Nongalactic Astrophysics
    Subject code 612
    Publishing date 2022-09-09
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Book ; Online: BeyondPlanck VI. Noise characterization and modelling

    Ihle, H. T. / Bersanelli, M. / Franceschet, C. / Gjerløw, E. / Andersen, K. J. / Aurlien, R. / Banerji, R. / Bertocco, S. / Brilenkov, M. / Carbone, M. / Colombo, L. P. L. / Eriksen, H. K. / Eskilt, J. R. / Foss, M. K. / Fuskeland, U. / Galeotta, S. / Galloway, M. / Gerakakis, S. / Hensley, B. /
    Herman, D. / Iacobellis, M. / Ieronymaki, M. / Jewell, J. B. / Karakci, A. / Keihänen, E. / Keskitalo, R. / Maggio, G. / Maino, D. / Maris, M. / Mennella, A. / Paradiso, S. / Partridge, B. / Reinecke, M. / San, M. / Suur-Uski, A. -S. / Svalheim, T. L. / Tavagnacco, D. / Thommesen, H. / Watts, D. J. / Wehus, I. K. / Zacchei, A.

    2020  

    Abstract: We present a Bayesian method for estimating instrumental noise parameters and propagating noise uncertainties within the global BeyondPlanck Gibbs sampling framework, and apply this to Planck Low Frequency Instrument (LFI) time-ordered data. Following ... ...

    Abstract We present a Bayesian method for estimating instrumental noise parameters and propagating noise uncertainties within the global BeyondPlanck Gibbs sampling framework, and apply this to Planck Low Frequency Instrument (LFI) time-ordered data. Following previous literature, we initially adopt a $1/f$ model for the noise power spectral density (PSD), but find the need for an additional lognormal component in the noise model for the 30 and 44\,GHz bands. We implement an optimal Wiener-filter (or constrained realization) gap-filling procedure to account for masked data. We then use this procedure to both estimate the gapless correlated noise in the time-domain, $n_\mathrm{corr}$, and to sample the noise PSD parameters, $\xi^n = \{\sigma_0, f_\mathrm{knee}, \alpha, A_\mathrm{p}\}$. In contrast to previous \textit{Planck} analyses, we assume piecewise stationary noise only within each pointing period (PID), not throughout the full mission, but we adopt the LFI Data Processing Center (DPC) results as priors on $\alpha$ and $f_\mathrm{knee}$. On average, we find best-fit correlated noise parameters that are mostly consistent with previous results, with a few notable exceptions. However, a detailed inspection of the time-dependent results reveals many important findings. First and foremost, we find strong evidence for statistically significant temporal variations in all noise PSD parameters, many of which are directly correlated with satellite housekeeping data. Second, while the simple $1/f$ model appears to be an excellent fit for the LFI 70 GHz channel, there is evidence for additional correlated noise not described by a $1/f$ model in the 30 and 44 GHz channels, including within the primary science frequency range of 0.1--1 Hz. (Abridged)

    Comment: 26 pages, 29 figures, as accepted in A&A
    Keywords Astrophysics - Cosmology and Nongalactic Astrophysics ; Astrophysics - Instrumentation and Methods for Astrophysics
    Subject code 612
    Publishing date 2020-11-12
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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