ArtDeco: a beam-deconvolution code for absolute cosmic microwave background measurements

Keihänen, E.; Reinecke, M.

doi:10.1051/0004-6361/201220183

Cited by 24 publications

(30 citation statements)

References 20 publications

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“…where σ max and σ min correspond to the widths of the best-fit Gaussian envelope to the semi-major and semi-minor axis of the co-polarized far field beam response. Beam asymmetries generate spurious polarization signals which can mimic an actual sky signal and bias science results [48][49][50][51][52].…”

Section: Ellipticitiesmentioning

confidence: 99%

Geometrical and physical optics analysis for mm-wavelength refractor telescopes designed to map the cosmic microwave background

Gudmundsson¹

2020

Appl. Opt.

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We present a compact two-lens HDPE f /1.6 refractor design that is capable of supporting a 28-deg diffractionlimited field of view at 1-mm wavelengths and contrast it to a similar two-lens refractor using silicon lenses. We compare the optical properties of these two systems as predicted by both geometrical and physical optics. The presented analysis suggests that by relaxing telecentricity requirements, a plastic two-lens refractor system can perform comparably to a similar silicon system across a wide field of view and wavelengths up to 1 mm. We show that for both telescope designs, cold stop spillover changes significantly across the field of view in a way that is somewhat inconsistent with Gaussian beam formalism and simple f -number scaling. We present results that highlight beam ellipticity dependence on both pixel location and pixel aperture sizean effect that is challenging to reproduce in standard geometrical optics. We show that a silicon refractor design suffers from larger cross-polarization compared to the HDPE design. Our results address the limitations of solely relying on geometrical optics to assess relative performance of two optical systems. We discuss implications for future refractor designs.

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Section: Ellipticitiesmentioning

confidence: 99%

Geometrical and physical optics analysis for mm-wavelength refractor telescopes designed to map the cosmic microwave background

Gudmundsson¹

2020

Appl. Opt.

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“…The code produces in output a set of harmonic coefficients a s m of the sky, up to some maximum value max . The algorithm is described in Keihänen & Reinecke (2012).…”

Section: Artdecomentioning

confidence: 99%

“…In this work we perform beam deconvolution on LFI data. We use the artDeco deconvolution code (Keihänen & Reinecke 2012) to correct for the asymmetric smearing produced by the detectors' beams. We take as our starting point the calibrated and destriped timelines for LFI detectors, now publicly available through the Planck Legacy Archive (PLA) 1 .…”

Section: Introductionmentioning

confidence: 99%

Beam-deconvolved Planck LFI maps

Keihänen

Lindholm

López‐Caniego

et al. 2019

A&A

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The Planck Collaboration made its final data release in 2018. In this paper we describe beam-deconvolution map products made from Planck LFI data using the artDeco deconvolution code to symmetrize the effective beam. The deconvolution results are auxiliary data products, available through the Planck Legacy Archive. Analysis of these deconvolved survey difference maps reveals signs of residual signal in the 30-GHz and 44-GHz frequency channels. We produce low-resolution maps and corresponding noise covariance matrices (NCVMs). The NCVMs agree reasonably well with the half-ring noise estimates except for 44 GHz, where we observe an asymmetry between EE and BB noise spectra, possibly a sign of further unresolved systematics.

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“…We constructed the harmonic NCVM matrix for multipoles up to max = 50. Beam elements with high k only affect the high multipoles (Keihänen & Reinecke 2012). We chose k max = 2 for this low-multipole computation.…”

Section: Constructing Ncvm For Planck Lfi Frequenciesmentioning

confidence: 99%

Impact of beam deconvolution on noise properties in CMB measurements: Application toPlanckLFI

Keihänen

Kiiveri

Lindholm

et al. 2016

A&A

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We present an analysis of the effects of beam deconvolution on noise properties in CMB measurements. The analysis is built around the artDeco beam deconvolver code. We derive a low-resolution noise covariance matrix that describes the residual noise in deconvolution products, both in harmonic and pixel space. The matrix models the residual correlated noise that remains in time-ordered data after destriping, and the effect of deconvolution on this noise. To validate the results, we generate noise simulations that mimic the data from the Planck LFI instrument. A χ 2 test for the full 70 GHz covariance in multipole range = 0−50 yields a mean reduced χ 2 of 1.0037. We compare two destriping options, full and independent destriping, when deconvolving subsets of available data. Full destriping leaves substantially less residual noise, but leaves data sets intercorrelated. We also derive a white noise covariance matrix that provides an approximation of the full noise at high multipoles, and study the properties on high-resolution noise in pixel space through simulations.

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ArtDeco: a beam-deconvolution code for absolute cosmic microwave background measurements

Cited by 24 publications

References 20 publications

Geometrical and physical optics analysis for mm-wavelength refractor telescopes designed to map the cosmic microwave background

Geometrical and physical optics analysis for mm-wavelength refractor telescopes designed to map the cosmic microwave background

Beam-deconvolved Planck LFI maps

Impact of beam deconvolution on noise properties in CMB measurements: Application toPlanckLFI

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