Markov chain beam randomization: a study of the impact of PLANCK beam measurement errors on cosmological parameter estimation

Rocha, G.; Pagano, L.; Górski, K. M.; Huffenberger, K. M.; Lawrence, C. R.; Lange, A. E.

doi:10.1051/0004-6361/200913032

Cited by 7 publications

(6 citation statements)

References 13 publications

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“…The Planck goal to achieve photometric calibration of 1% in the key CMB bands (70−217 GHz) implies that the beam characteristics (solid angle, shape) must be known to sub-% levels. The impact of beam uncertainties has been extensively analysed for WMAP (e.g., Hill et al 2009;Nolta et al 2009) and analyses of the effect on the recovery by Planck of some cosmological parameters have also been performed (Huffenberger et al 2010;Rocha et al 2010), in both cases confirming the importance of optical uncertainties.…”

Section: Introductionmentioning

confidence: 97%

Planckpre-launch status: The optical system

Tauber¹,

Nørgaard-Nielsen²,

Ade

et al. 2010

A&A

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Planck is a scientific satellite that represents the next milestone in space-based research related to the cosmic microwave background, and in many other astrophysical fields. Planck was launched on 14 May of 2009 and is now operational. The uncertainty in the optical response of its detectors is a key factor allowing Planck to achieve its scientific objectives. More than a decade of analysis and measurements have gone into achieving the required performances. In this paper, we describe the main aspects of the Planck optics that are relevant to science, and the estimated in-flight performance, based on the knowledge available at the time of launch. We also briefly describe the impact of the major systematic effects of optical origin, and the concept of in-flight optical calibration. Detailed discussions of related areas are provided in accompanying papers.

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Section: Introductionmentioning

confidence: 97%

Planckpre-launch status: The optical system

Tauber¹,

Nørgaard-Nielsen²,

Ade

et al. 2010

A&A

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“…As done in 2013 release we apply the Markov Chain Beam Randomization (Rocha et al 2010) procedure to a simulated 70 GHz dataset. We found that the impact for all the ΛCDM parameters is well below 10% of σ confirming that the uncertainty on beam knowledge is negligible in the cosmological parameter estimation.…”

Section: Error Budgetmentioning

confidence: 99%

Planck2015 results

Ade

Aghanim

Ashdown

et al. 2016

A&A

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This paper presents the characterization of the in-flight beams, the beam window functions, and the associated uncertainties for the Planck Low Frequency Instrument (LFI). The structure of the paper is similar to that presented in the 2013 Planck release; the main differences concern the beam normalization and the delivery of the window functions to be used for polarization analysis. The in-flight assessment of the LFI main beams relies on measurements performed during observations of Jupiter. By stacking data from seven Jupiter transits, the main beam profiles are measured down to -25 dB at 30 and 44 GHz, and down to -30 dB at 70 GHz. It has been confirmed that the agreement between the simulated beams and the measured beams is better than 1% at each LFI frequency band (within the 20 dB contour from the peak, the rms values are 0.1% at 30 and 70 GHz; 0.2% at 44 GHz). Simulated polarized beams are used for the computation of the effective beam window functions. The error budget for the window functions is estimated from both main beam and sidelobe contributions, and accounts for the radiometer band shapes. The total uncertainties in the effective beam window functions are 0.7% and 1% at 30 and 44 GHz, respectively (at ≈ 600); and 0.5% at 70 GHz (at ≈ 1000).

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“…Figures 23 and 24 show the eigenmodes for the 44 and 30 GHz, respectively. The eigenmodes can be used as input of the Markov Chain Beam Randomization (MCBR) marginalization code to account for beam errors in cosmological parameter estimation (Rocha et al 2010). We apply the MCBR procedure to a simulated 70 GHz dataset, finding that the parameters mostly affected are n s , Ω b h 2 , Ω c h 2 , and A s ; the increase in the errors can be quantified respectively as 12% of σ for the first and less then 8% of σ for the others.…”

Section: Total Error Budget In Window Functionsmentioning

confidence: 99%

Planck2013 results. IV. Low Frequency Instrument beams and window functions

Aghanim¹,

Armitage-Caplan²,

Arnaud³

et al. 2014

A&A

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This paper presents the characterization of the in-flight beams, the beam window functions, and the associated uncertainties for the Planck Low Frequency Instrument (LFI). Knowledge of the beam profiles is necessary for determining the transfer function to go from the observed to the actual sky anisotropy power spectrum. The main beam distortions affect the beam window function, complicating the reconstruction of the anisotropy power spectrum at high multipoles, whereas the sidelobes affect the low and intermediate multipoles. The in-flight assessment of the LFI main beams relies on the measurements performed during Jupiter observations. By stacking the data from multiple Jupiter transits, the main beam profiles are measured down to -20 dB at 30 and 44 GHz, and down to -25 dB at 70 GHz. The main beam solid angles are determined to better than 0.2% at each LFI frequency band. The Planck pre-launch optical model is conveniently tuned to characterize the main beams independently of any noise effects. This approach provides an optical model whose beams fully reproduce the measurements in the main beam region, but also allows a description of the beams at power levels lower than can be achieved by the Jupiter measurements themselves. The agreement between the simulated beams and the measured beams is better than 1% at each LFI frequency band. The simulated beams are used for the computation of the window functions for the effective beams. The error budget for the window functions is estimated from both main beam and sidelobe contributions, and accounts for the radiometer bandshapes. The total uncertainties in the effective beam window functions are: 2% and 1.2% at 30 and 44 GHz, respectively (at ≈ 600), and 0.7% at 70 GHz (at ≈ 1000).

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Markov chain beam randomization: a study of the impact of PLANCK beam measurement errors on cosmological parameter estimation

Cited by 7 publications

References 13 publications

Planckpre-launch status: The optical system

Planckpre-launch status: The optical system

Planck2015 results

Planck2013 results. IV. Low Frequency Instrument beams and window functions

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