BeyondPlanck VII. Bayesian estimation of gain and absolute calibration for CMB experiments

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

doi:10.48550/arxiv.2011.08082

Cited by 7 publications

(24 citation statements)

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“…Specifically, g 0 is sampled using the orbital CMB dipole only as a calibration source, ∆g j is sampled using the full astrophysical sky model, including the Solar dipole, and δg t, j is sampled using an optimal Wiener filter algorithm that weights time-variable fluctuations according to their relative signal-to-noise ratio. For full details, we refer the interested reader to Gjerløw et al (2022). From Eq.…”

Section: Gain and Imbalance Samplingmentioning

confidence: 99%

“…The 9-year best-fit parameters are given in Appendix A of Greason et al (2012). In contrast, the Commander framework calibrates the time-ordered data on a weekly cadence by comparing directly to the expected sky amplitude, and most importantly to the orbital and Solar CMB dipoles; for full details, see Gjerløw et al (2022). The Commander approach makes fewer assumptions regarding the physical origin of gain fluctuations, but stronger assumptions regarding their stability in time.…”

Section: Differences Between the Cosmoglobe And Wmap Pipelinesmentioning

confidence: 99%

“…The resulting transmission imbalance templates were projected out from low-resolution noise covariance matrices to account for their effect on cosmological parameters. In contrast, the current analysis assumes a constant imbalance parameter for the entire mission, but allows this to vary in each Gibbs iteration, and thereby marginalizes over this parameter directly in the data model, fully analogous to the gain (Gjerløw et al 2022).…”

Section: Differences Between the Cosmoglobe And Wmap Pipelinesmentioning

confidence: 99%

“…-Solar dipole: While the WMAP team subtracted an estimate of the Solar dipole from the time-ordered data before mapmaking, resulting in dipole-free frequency maps (Hinshaw et al 2003), Commander retains it for calibration and component separation purposes, following Planck DR4 (Planck Collaboration Int. LVII 2020; Gjerløw et al 2022;Andersen et al 2022). -Mapmaking: The WMAP team accounted for correlated noise weighting by estimating a two-point correlation function in time-domain, and used this to pre-whiten the TOD prior to mapmaking.…”

Section: Differences Between the Cosmoglobe And Wmap Pipelinesmentioning

confidence: 99%

“…A second important example is COBE/FIRAS (Mather et al 1994), which showed that the CMB is well-described by the Planck blackbody radiation law at a temperature of T = 2.72548 ± 0.00057 K (Fixsen 2009); despite being now more than 20 years old, this experiment has not yet been improved upon, and all later CMB experiments rely directly on this value as a strong prior for calibration purposes (e.g., Bennett et al 2013;Planck Collaboration V 2020;Gjerløw et al 2022). A third example is the COBE/DIRBE experiment (Hauser et al 1998), which still represents the state-of-the-art in terms of submillimeter zodiacal light observations (Kelsall et al 1998;Planck Collaboration XIV 2014), due to its unique combination of frequency and sky coverage.…”

Section: Introductionmentioning

confidence: 99%

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From BeyondPlanck to Cosmoglobe: Preliminary $\mathit{WMAP}$ $\mathit Q$-band analysis

Watts,

Galloway,

Ihle

et al. 2022

Preprint

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We present the first application of the Cosmoglobe analysis framework by analyzing 9-year WMAP time-ordered observations using similar machinery as BeyondPlanck utilizes for Planck LFI. We analyze only the Q1-band (41 GHz) data and report on the lowlevel analysis process from uncalibrated time-ordered data to calibrated maps. Most of the existing BeyondPlanck pipeline may be reused for WMAP analysis with minimal changes to the existing codebase. The main modification is the implementation of the same preconditioned biconjugate gradient mapmaker used by the WMAP team. Producing a single WMAP Q1-band sample requires 44 CPU-hrs, which is less than the cost of a Planck 70 GHz sample of 69 CPU-hrs; this demonstrates that full end-to-end Bayesian processing of the WMAP data is computationally feasible. Our recovered maps are generally similar to the maps released by the WMAP team, but more work is needed on sidelobe modeling before the new pipeline is ready for science grade production. While comparing the Cosmoglobe and WMAP polarization maps, we identify the same large-scale pattern in the Q1-band as was previously reported in the V-and W-band polarization maps by the WMAP team, and we show that this morphology may be reproduced deterministically in terms of temperature-to-polarization leakage arising from the coupling between the CMB Solar dipole, transmission imbalance, and sidelobes. Given that this structure is present in the Q1-, V-, and W-bands, it could have a nonnegligible impact on cosmological and astrophysical conclusions drawn from these polarized maps.

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Section: Gain and Imbalance Samplingmentioning

confidence: 99%

Section: Differences Between the Cosmoglobe And Wmap Pipelinesmentioning

confidence: 99%

Section: Differences Between the Cosmoglobe And Wmap Pipelinesmentioning

confidence: 99%

Section: Differences Between the Cosmoglobe And Wmap Pipelinesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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From BeyondPlanck to Cosmoglobe: Preliminary $\mathit{WMAP}$ $\mathit Q$-band analysis

Watts,

Galloway,

Ihle

et al. 2022

Preprint

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Beyondplanck

Andersen¹,

Herman²,

Aurlien³

et al. 2023

A&A

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We present the intensity foreground algorithms and model employed within the BeyondPlanck analysis framework. The Beyond-Planck 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 BeyondPlanck 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 Miramare; 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 BeyondPlanck 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 Cosmoglobe community effort.

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From BEYONDPLANCK to COSMOGLOBE: Preliminary WMAP Q-band analysis

Watts¹,

Galloway²,

Ihle³

et al. 2023

A&A

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We present the first application of the Cosmoglobe analysis framework by analyzing nine-year WMAP time-ordered observations that uses similar machinery to that of BeyondPlanck for the Planck Low Frequency Instrument (LFI). We analyzed only the Q-band (41 GHz) data and report on the low-level analysis process based on uncalibrated time-ordered data to calibrated maps. Most of the existing BeyondPlanck pipeline may be reused for WMAP analysis with minimal changes to the existing codebase. The main modification is the implementation of the same preconditioned biconjugate gradient mapmaker used by the WMAP team. Producing a single WMAP Q1-band sample requires 22 CPU-hrs, which is slightly more than the cost of a Planck 44 GHz sample of 17 CPU-hrs; this demonstrates that a full end-to-end Bayesian processing of the WMAP data is computationally feasible. In general, our recovered maps are very similar to the maps released by the WMAP team, although with two notable differences. In terms of temperature, we find a ∼ 2 µK quadrupole difference that most likely is caused by different gain modeling, while in polarization we find a distinct 2.5 µK signal that has been previously referred to as poorly measured modes by the WMAP team. In the Cosmoglobe processing, this pattern arises from temperature-to-polarization leakage from the coupling between the CMB Solar dipole, transmission imbalance, and sidelobes. No traces of this pattern are found in either the frequency map or TOD residual map, suggesting that the current processing has succeeded in modeling these poorly measured modes within the assumed parametric model by using Planck information to break the sky-synchronous degeneracies inherent in the WMAP scanning strategy.

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BeyondPlanck VII. Bayesian estimation of gain and absolute calibration for CMB experiments

Cited by 7 publications

References 0 publications

From BeyondPlanck to Cosmoglobe: Preliminary $\mathit{WMAP}$ $\mathit Q$-band analysis

From BeyondPlanck to Cosmoglobe: Preliminary $\mathit{WMAP}$ $\mathit Q$-band analysis

Beyondplanck

From BEYONDPLANCK to COSMOGLOBE: Preliminary WMAP Q-band analysis

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