ABS: an analytical method of blind separation of CMB from foregrounds

Zhang, Pengjie; Zhang, Jun; Le, Zhang

doi:10.1093/mnras/stz091

Cited by 10 publications

(9 citation statements)

References 49 publications

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“…A method to directly estimate the angular power spectrum of the CMB from the multivariate angular power spectrum of multifrequency observations was proposed by Zhang et al (2019). This method, called the analytical method of blind separation (ABS), shares conceptual elements with SMICA (both methods estimate the CMB angular power spectrum first before any separation of component maps), as well as with the ILC (see Sect.…”

Section: The Abs Methodsmentioning

confidence: 99%

“…It uses the measured cross-band power between different frequency bands, from which the CMB power spectrum can be solved analytically, avoiding a multi-parameter fitting procedure. A description of the mathematical formalism and numerical techniques was provided by Zhang et al (2019). The ABS method was also tested against simulated temperature maps observed by the Planck space mission (Yao et al 2018).…”

Section: The Abs Methodsmentioning

confidence: 99%

“…In this paper, we discuss the estimation of CMB E-mode and B-mode power spectra in the presence of foreground contamination using the ABS method (Zhang et al 2019). We test ABS analyses of both the full sky and part of the sky to compare its performance in these two cases.…”

Section: Introductionmentioning

confidence: 99%

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Testing the analytical blind separation method in simulated CMB polarization maps

Santos

Yao

et al. 2021

A&A

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Context. Multi-frequency observations are needed to separate the cosmic microwave background (CMB) from foreground emission and accurately extract cosmological information from the data. The analytical blind separation (ABS) method is dedicated to extracting the CMB power spectrum from multi-frequency observations in the presence of contamination from astrophysical foreground emission and instrumental noise. Aims. In this study, we apply the ABS method to simulated sky maps as could be observed with a future space-borne survey in order to test its capability of determining the CMB polarization E- and B-mode power spectra. Methods. We present the ABS method performance on simulations for both a full-sky analysis and for an analysis concentrating on sky regions less impacted by Galactic foreground emission. Results. We discuss the origin and minimization of biases in the estimated CMB polarization angular power spectra. We find that the ABS method performs quite well for the analysis of full-sky observations at intermediate and small angular scales, in spite of strong foreground contamination. On the largest scales, extra work is still required to reduce biases of various origins and the impact of confusion between CMB E and B polarization for partial sky analyses.

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Section: The Abs Methodsmentioning

confidence: 99%

Section: The Abs Methodsmentioning

confidence: 99%

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Testing the analytical blind separation method in simulated CMB polarization maps

Santos

Yao

et al. 2021

A&A

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“…The analytic blind separation (ABS) method is a novel, computationally efficient method for the blind separation of the CMB from foregrounds [67], which has been tested extensively for extracting the CMB temperature and polarization E-and B-mode power spectra from the simulated maps [44,68]. The ABS estimator acts directly on measured multi-frequency cross band powers, which extracts CMB power spectra by projecting the data onto CMB subspace.…”

Section: Abs Pipelinementioning

confidence: 99%

Performance forecasts for the primordial gravitational wave detection pipelines for AliCPT-1

Ghosh,

Liu,

Zhang

et al. 2022

Preprint

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AliCPT is the first Chinese cosmic microwave background (CMB) experiment which will make the most precise measurements of the CMB polarization in the northern hemisphere. The key science goal for AliCPT is the detection of primordial gravitational waves (PGWs). It is well known that an epoch of cosmic inflation, in the very early universe, can produce PGWs, which leave an imprint on the CMB in form of odd parity B-mode polarization. In this work, we study the performance of the component separation and parameter estimation pipelines in context of constraining the value of the tensor-to-scalar ratio. Based on the simulated data for one observation season, we compare five different pipelines with different working principles. Three pipelines perform component separation at map or spectra level before estimating r from the cleaned spectra, while the other two pipelines performs a global fit for both foreground parameters and r. We also test different methods to account for the effects of time stream filtering systematics. This work shows that our pipelines provide consistent and robust constraints on the tensor-to-scalar ratio and a consistent sensitivity σprq " 0.02. This showcases the potential of precise B-mode polarization measurement with AliCPT-1. AliCPT will provide a powerful opportunity to detect PGWs, which is complementary with various ground-based CMB experiments in the southern hemisphere.

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“…Since foregrounds are smooth in frequency, in principle most of them could be extracted from the map. For example, for the CMB many tools are available for components separation based on multi-color maps, e.g., Remazeilles et al (2011); Zhang et al (2019). In Fig.…”

Section: Continuum Foregroundsmentioning

confidence: 99%

Studying high-z galaxies with [CII] intensity mapping

Yue,

Ferrara

2019

Preprint

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We investigate the [CII] line intensity mapping (IM) signal from galaxies in the Epoch of Reionization (EoR) to assess its detectability, the possibility to constrain the L CII − SFR relation, and to recover the [CII] luminosity function (LF) from future experiments. By empirically assuming that logL CII = logA + γSFR ± σ L , we derive the [CII] LF from the observed UV LF, and the [CII] IM power spectrum. We study the shot-noise and the full power spectrum separately. Although, in general, the shot-noise component has a much higher signal-to-noise ratio than the clustering one, it cannot be used to put independent constraints on logA and γ. Full power spectrum measurements are crucial to break such degeneracy, and reconstruct the [CII] LF. In our fiducial survey S1 (inspired by CCAT-p/1000 hr) at z ∼ 6, the shot-noise (clustering) signal is detectable for 2 (1) of the 5 considered L CII −SFR relations. The shot-noise is generally dominated by galaxies with L CII 10 8−9 L (M UV ∼ −20 to −22), already at reach of ALMA pointed observations. However, given the small field of view of such telescope, an IM experiment would provide unique information on the bright-end of the LF. The detection depth of an IM experiment crucially depends on the (poorly constrained) L CII − SFR relation in the EoR. If the L CII − SFR relation varies in a wide logA -γ range, but still consistent with ALMA [CII] LF upper limits, even the signal from galaxies with L CII as faint as ∼ 10 7 L could be detectable. Finally, we consider the contamination by continuum foregrounds (cosmic infrared background, dust, CMB) and CO interloping lines, and derive the requirements on the residual contamination level to reliably extract the [CII] signal.

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ABS: an analytical method of blind separation of CMB from foregrounds

Cited by 10 publications

References 49 publications

Testing the analytical blind separation method in simulated CMB polarization maps

Testing the analytical blind separation method in simulated CMB polarization maps

Performance forecasts for the primordial gravitational wave detection pipelines for AliCPT-1

Studying high-z galaxies with [CII] intensity mapping

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