skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: No evidence for dust B -mode decorrelation in Planck data

Abstract

Constraints on inflationary B modes using cosmic microwave background polarization data commonly rely on either template cleaning or cross-spectra between maps at different frequencies to disentangle Galactic foregrounds from the cosmological signal. Assumptions about how the foregrounds scale with frequency are therefore crucial to interpreting the data. Recent results from the Planck satellite collaboration claim significant evidence for a decorrelation in the polarization signal of the spatial pattern of Galactic dust between 217 and 353 GHz. Such a decorrelation would suppress power in the cross-spectrum between high-frequency maps, where the dust is strong, and lower-frequency maps, where the sensitivity to cosmological B modes is strongest. Alternatively, it would leave residuals in lower-frequency maps cleaned with a template derived from the higher-frequency maps. If not accounted for, both situations would result in an underestimate of the dust contribution and thus an upward bias on measurements of the tensor-to-scalar ratio, r. In this paper, we revisit this measurement and find that the no-decorrelation hypothesis cannot be excluded with the Planck data. There are three main reasons for this: (i) There is significant noise bias in cross-spectra between Planck data splits that needs to be accounted for. (ii) There is strong evidence formore » unknown instrumental systematics, the amplitude of which we estimate using alternative Planck data splits. (iii) There are significant correlations between measurements in different sky patches that need to be taken into account when assessing the statistical significance. Finally, between ℓ = 55-90 and over 72% of the sky, the dust BB correlation between 217 and 353 GHz is 1.001 +.004/.021-.004/.000 (68% stat/syst.) and shows no significant trend with the sky fraction.« less

Authors:
 [1];  [1]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States). Physics Dept.
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE; BNL Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1430840
Report Number(s):
BNL-203365-2018-JAAM
Journal ID: ISSN 2470-0010; TRN: US1802625
Grant/Contract Number:  
SC0012704
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 97; Journal Issue: 4; Journal ID: ISSN 2470-0010
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; cosmic microwave background; inflation; radio, microwave, & sub-mm astronomy

Citation Formats

Sheehy, Christopher, and Slosar, Anze. No evidence for dust B -mode decorrelation in Planck data. United States: N. p., 2018. Web. doi:10.1103/PhysRevD.97.043522.
Sheehy, Christopher, & Slosar, Anze. No evidence for dust B -mode decorrelation in Planck data. United States. doi:10.1103/PhysRevD.97.043522.
Sheehy, Christopher, and Slosar, Anze. Tue . "No evidence for dust B -mode decorrelation in Planck data". United States. doi:10.1103/PhysRevD.97.043522. https://www.osti.gov/servlets/purl/1430840.
@article{osti_1430840,
title = {No evidence for dust B -mode decorrelation in Planck data},
author = {Sheehy, Christopher and Slosar, Anze},
abstractNote = {Constraints on inflationary B modes using cosmic microwave background polarization data commonly rely on either template cleaning or cross-spectra between maps at different frequencies to disentangle Galactic foregrounds from the cosmological signal. Assumptions about how the foregrounds scale with frequency are therefore crucial to interpreting the data. Recent results from the Planck satellite collaboration claim significant evidence for a decorrelation in the polarization signal of the spatial pattern of Galactic dust between 217 and 353 GHz. Such a decorrelation would suppress power in the cross-spectrum between high-frequency maps, where the dust is strong, and lower-frequency maps, where the sensitivity to cosmological B modes is strongest. Alternatively, it would leave residuals in lower-frequency maps cleaned with a template derived from the higher-frequency maps. If not accounted for, both situations would result in an underestimate of the dust contribution and thus an upward bias on measurements of the tensor-to-scalar ratio, r. In this paper, we revisit this measurement and find that the no-decorrelation hypothesis cannot be excluded with the Planck data. There are three main reasons for this: (i) There is significant noise bias in cross-spectra between Planck data splits that needs to be accounted for. (ii) There is strong evidence for unknown instrumental systematics, the amplitude of which we estimate using alternative Planck data splits. (iii) There are significant correlations between measurements in different sky patches that need to be taken into account when assessing the statistical significance. Finally, between ℓ = 55-90 and over 72% of the sky, the dust BB correlation between 217 and 353 GHz is 1.001 +.004/.021-.004/.000 (68% stat/syst.) and shows no significant trend with the sky fraction.},
doi = {10.1103/PhysRevD.97.043522},
journal = {Physical Review D},
number = 4,
volume = 97,
place = {United States},
year = {2018},
month = {2}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 4 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Joint Analysis of BICEP2/ Keck Array and Planck Data
journal, March 2015


Planck intermediate results : XLIV. Structure of the Galactic magnetic field from dust polarization maps of the southern Galactic cap
journal, December 2016


Signature of Gravity Waves in the Polarization of the Microwave Background
journal, March 1997


The pre-launch Planck Sky Model: a model of sky emission at submillimetre to centimetre wavelengths
journal, May 2013


Measuring Polarization in the Cosmic Microwave Background
journal, June 1997

  • Seljak, Uroš
  • The Astrophysical Journal, Vol. 482, Issue 1
  • DOI: 10.1086/304123

Planck 2015 results : VIII. High Frequency Instrument data processing: Calibration and maps
journal, September 2016


XSPECT, estimation of the angular power spectrum by computing cross-power spectra with analytical error bars
journal, April 2005


Gravitational lensing effect on cosmic microwave background polarization
journal, June 1998


The Python Sky Model: software for simulating the Galactic microwave sky
journal, May 2017

  • Thorne, B.; Dunkley, J.; Alonso, D.
  • Monthly Notices of the Royal Astronomical Society, Vol. 469, Issue 3
  • DOI: 10.1093/mnras/stx949

Planck 2015 results : XII. Full focal plane simulations
journal, September 2016


A Probe of Primordial Gravity Waves and Vorticity
journal, March 1997


HEALPix: A Framework for High‐Resolution Discretization and Fast Analysis of Data Distributed on the Sphere
journal, April 2005

  • Gorski, K. M.; Hivon, E.; Banday, A. J.
  • The Astrophysical Journal, Vol. 622, Issue 2
  • DOI: 10.1086/427976

Planck 2013 results. XVI. Cosmological parameters
journal, October 2014


Line-of-sight extrapolation noise in dust polarization
journal, May 2017


Searching for inflationary B modes: can dust emission properties be extrapolated from 350 GHz to 150 GHz?
journal, June 2015

  • Tassis, Konstantinos; Pavlidou, Vasiliki
  • Monthly Notices of the Royal Astronomical Society: Letters, Vol. 451, Issue 1
  • DOI: 10.1093/mnrasl/slv077

Planck 2013 results. XI. All-sky model of thermal dust emission
journal, October 2014


Fast estimation of polarization power spectra using correlation functions
journal, May 2004


    Works referencing / citing this record:

    Statistical properties of polarized CMB foreground maps
    journal, June 2019

    • von Hausegger, Sebastian; Gammelgaard Ravnebjerg, Aske; Liu, Hao
    • Monthly Notices of the Royal Astronomical Society, Vol. 487, Issue 4
    • DOI: 10.1093/mnras/stz1582

    Statistical properties of polarized CMB foreground maps
    journal, June 2019

    • von Hausegger, Sebastian; Gammelgaard Ravnebjerg, Aske; Liu, Hao
    • Monthly Notices of the Royal Astronomical Society, Vol. 487, Issue 4
    • DOI: 10.1093/mnras/stz1582