A deconvolution map-making method for experiments with circular scanning strategies

Harrison, D. L.; Leeuwen, F. van; Ashdown, M.

doi:10.1051/0004-6361/201116986

Cited by 7 publications

(6 citation statements)

References 17 publications

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“…If the instrument beams display complex, non-axially symmetric structure, the proper estimation of the sky signal may require correcting for their effects at the map level, leading to the so-called deconvolution map-making [580,581,582]. However, further work is needed to demonstrate the effectiveness of such an approach in general.…”

Section: Map-makingmentioning

confidence: 99%

CMB-S4 Science Book, First Edition

Abazajian¹,

Adshead²,

Ahmed³

et al. 2016

Preprint

921

1,474

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The next generation "Stage-4" ground-based cosmic microwave background (CMB) experiment, CMB-S4, consisting of dedicated telescopes equipped with highly sensitive superconducting cameras operating at the South Pole, the high Chilean Atacama plateau, and possibly northern hemisphere sites, will provide a dramatic leap forward in our understanding of the fundamental nature of space and time and the evolution of the Universe. CMB-S4 will be designed to cross critical thresholds in testing inflation, determining the number and masses of the neutrinos, constraining possible new light relic particles, providing precise constraints on the nature of dark energy, and testing general relativity on large scales.CMB-S4 is intended to be the definitive ground-based CMB project. It will deliver a highly constraining data set with which any model for the origin of the primordial fluctuations-be it inflation or an alternative theory-and their evolution to the structure seen in the Universe today must be consistent. While we have learned a great deal from CMB measurements, including discoveries that have pointed the way to new physics, we have only begun to tap the information encoded in CMB polarization, CMB lensing and other secondary effects. The discovery space from these and other yet to be imagined effects will be maximized by designing CMB-S4 to produce high-fidelity maps, which will also ensure enormous legacy value for CMB-S4. CMB-S4 is the logical successor to the Stage-3 CMB projects which will operate over the next few years. For maximum impact, CMB-S4 should be implemented on a schedule that allows a transition from Stage 3 to Stage 4 that is as seamless and as timely as possible, preserving the expertise in the community and ensuring a continued stream of CMB science results. This timing is also necessary to ensure the optimum synergistic enhancement of the science return from contemporaneous optical surveys (e.g., LSST, DESI, Euclid and WFIRST). Information learned from the ongoing Stage-3 experiments can be easily incorporated into CMB-S4 with little or no impact on its design. In particular, additional information on the properties of Galactic foregrounds would inform the detailed distribution of detectors among frequency bands in CMB-S4. The sensitivity and fidelity of the multiple band foreground measurements needed to realize the goals of CMB-S4 will be provided by CMB-S4 itself, at frequencies just below and above those of the main CMB channels. This timeline is possible because CMB-S4 will use proven existing technology that has been developed and demonstrated by the CMB experimental groups over the last decade. There are, to be sure, considerable technical challenges presented by the required scaling-up of the instrumentation and by the scope and complexity of the data analysis and interpretation. CMB-S4 will require: scaled-up superconducting detector arrays with well-understood and robust material properties and processing techniques; high-throughput mmwave telescopes and optics with unprecedented precisi...

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Section: Map-makingmentioning

confidence: 99%

CMB-S4 Science Book, First Edition

Abazajian¹,

Adshead²,

Ahmed³

et al. 2016

Preprint

921

1,474

View full text Add to dashboard Cite

show abstract

“…From these one can derive temperature and Q and U polarisation maps. This is the usual deconvolution map-making problem (see, e.g., Armitage & Wandelt 2004;Armitage-Caplan & Wandelt 2009;Harrison et al 2011). Our method differs from the earlier works by an efficient reformulation of the deconvolution problem through heavy use of Wigner functions.…”

Section: Introductionmentioning

confidence: 99%

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

Keihänen

Reinecke

2012

A&A

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We present a method for beam-deconvolving cosmic microwave background (CMB) anisotropy measurements. The code takes as input the time-ordered data along with the corresponding detector pointings and known beam shapes, and produces as output the harmonic a T lm , a Elm , and a Blm coefficients of the observed sky. From these one can derive temperature and Q and U polarisation maps. The method is applicable to absolute CMB measurements with wide sky coverage, and is independent of the scanning strategy. We tested the code with extensive simulations, mimicking the resolution and data volume of Planck 30 GHz and 70 GHz channels, but with exaggerated beam asymmetry. We applied it to multipoles up to l = 1700 and examined the results in both pixel space and harmonic space. We also tested the method in presence of white noise.

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“…If beams happen to be strongly asymmetric to the extent that it is necessary to correct for it on the map-making stage, the data model in Eq. ( 14) would still apply and though the pointing matrix would be in such a case dense, it would be also structured, permitting specialized algorithms for the map-making problem as have been indeed proposed [3,18,23]. In the framework discussed here the focus to date has been specifically on the cases with an arbitrary but sparse pointing matrix.…”

Section: Pointing Matrixmentioning

confidence: 99%

“…We also exclude the atmospheric noise from the input, and instead artificially increase the instrumental noise f knee to 1 Hz. We assume a half bandwidth, λ = 2 18 , corresponding to a correlation length of about 33 minutes. This configuration results in a degraded conditioning of the system matrix showcasing the ability of the ECG solver to deal with such cases.…”

Section: Solvers and Preconditioners Performance Enlarged Cgmentioning

confidence: 99%

MAPPRAISER: A massively parallel map-making framework for multi-kilo pixel CMB experiments

Bouhargani,

Jamal,

Beck

et al. 2021

Preprint

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Forthcoming cosmic microwave background (CMB) polarized anisotropy experiments have the potential to revolutionize our understanding of the Universe and fundamental physics. The sought-after, tale-telling signatures will be however distributed over voluminous data sets which these experiments will collect. These data sets will need to be efficiently processed and unwanted contributions due to astrophysical, environmental, and instrumental effects characterized and efficiently mitigated in order to uncover the signatures. This poses a significant challenge to data analysis methods, techniques, and software tools which will not only have to be able to cope with huge volumes of data but to do so with unprecedented precision driven by the demanding science goals posed for the new experiments.A keystone of efficient CMB data analysis are solvers of very large linear systems of equations. Such systems appear in very diverse contexts throughout CMB data analysis pipelines, however they typically display similar algebraic structures and can therefore be solved using similar numerical techniques. Linear systems arising in the so-called map-making problem are one of the most prominent and common ones.In this work we present a massively parallel, flexible and extensible framework, comprised of a numerical library, MIDAPACK, and a high level code, MAPPRAISER, which provide tools for solving efficiently such systems. The framework implements iterative solvers based on conjugate gradient techniques: enlarged and preconditioned using different preconditioners. We demonstrate the framework on simulated examples reflecting basic characteristics of the forthcoming data sets issued by ground-based and satelliteborne instruments, executing it on as many as 16,384 compute cores. The software is developed as an open source project freely available to the community at: https://github.com/B3Dcmb/midapack.

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A deconvolution map-making method for experiments with circular scanning strategies

Cited by 7 publications

References 17 publications

CMB-S4 Science Book, First Edition

CMB-S4 Science Book, First Edition

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

MAPPRAISER: A massively parallel map-making framework for multi-kilo pixel CMB experiments

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