Planck intermediate results. L. Evidence for spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB $B$-mode analysis

P.A.R Ade; N. Aghanim; J. Aumont; C. Baccigalupi; Rosa Maria  Ballardini; A.J. Banday; R.B. Barreiro; N. Bartolo; S. Basak; K. Benabed; Pavel Nasselski; Igor Dmitrievich Novikov; Hans Ulrik Nørgaard-Nielsen; A. Zacchei; P. Vielva; A. Zonca

doi:10.1051/0004-6361/201629164

Planck intermediate results. L. Evidence for spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB $B$-mode analysis

P.A.R Ade, N. Aghanim, J. Aumont, C. Baccigalupi, Rosa Maria Ballardini, A.J. Banday, R.B. Barreiro, N. Bartolo, S. Basak, K. Benabed, Pavel Nasselski, Igor Dmitrievich Novikov, Hans Ulrik Nørgaard-Nielsen, A. Zacchei, P. Vielva, A. Zonca

Theoretical high energy, astroparticle and gravitational physics

16 Citations (Scopus)

Abstract

The characterization of the Galactic foregrounds has been shown to be the main obstacle in thechallenging quest to detect primordial B-modes in the polarized microwave sky. We make use of the Planck-HFI 2015 data release at high frequencies to place new constraints on the properties of the polarized thermal dust emission at high Galactic latitudes. Here, we specifically study the spatial variability of the dust polarized spectral energy distribution (SED), and its potential impact on the determination of the tensor-to-scalar ratio, r. We use the correlation ratio of the angular power spectra between the 217 and 353 GHz channels as a tracer of these potential variations, computed on different high Galactic latitude regions, ranging from 80% to 20% of the sky. The new insight from Planck data is a departure of the correlation ratio from unity that cannot be attributed to a spurious decorrelation due to the cosmic microwave background, instrumental noise, or instrumental systematics. The effect is marginally detected on each region, but the statistical combination of all the regions gives more than 99% confidence for this variation in polarized dust properties. In addition, we show that the decorrelation increases when there is a decrease in the mean column density of the region of the sky being considered, and we propose a simple power-law empirical model for this dependence, which matches what is seen in the Planck data. We explore the effect that this measured decorrelation has on simulations of the BICEP2-Keck Array/Planck analysis and show that the 2015 constraints from these data still allow a decorrelation between the dust at 150 and 353 GHz that is compatible with our measured value. Finally, using simplified models, we show that either spatial variation of the dust SED or of the dust polarization angle are able to produce decorrelations between 217 and 353 GHz data similar to the values we observe in the data.

Original language	English
Article number	A51
Journal	Astronomy & Astrophysics
Volume	599
ISSN	0004-6361
DOIs	https://doi.org/10.1051/0004-6361/201629164
Publication status	Published - 1 Mar 2017

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Ade, P. A. R., Aghanim, N., Aumont, J., Baccigalupi, C., Ballardini, R. M., Banday, A. J., Barreiro, R. B., Bartolo, N., Basak, S., Benabed, K., Nasselski, P., Novikov, I. D., Nørgaard-Nielsen, H. U., Zacchei, A., Vielva, P., & Zonca, A. (2017). Planck intermediate results. L. Evidence for spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB $B$-mode analysis. Astronomy & Astrophysics, 599, Article A51. https://doi.org/10.1051/0004-6361/201629164

Ade, PAR, Aghanim, N, Aumont, J, Baccigalupi, C, Ballardini, RM, Banday, AJ, Barreiro, RB, Bartolo, N, Basak, S, Benabed, K, Nasselski, P, Novikov, ID, Nørgaard-Nielsen, HU, Zacchei, A, Vielva, P & Zonca, A 2017, 'Planck intermediate results. L. Evidence for spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB $B$-mode analysis', Astronomy & Astrophysics, vol. 599, A51. https://doi.org/10.1051/0004-6361/201629164

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title = "Planck intermediate results. L. Evidence for spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB $B$-mode analysis",

abstract = "The characterization of the Galactic foregrounds has been shown to be the main obstacle in thechallenging quest to detect primordial B-modes in the polarized microwave sky. We make use of the Planck-HFI 2015 data release at high frequencies to place new constraints on the properties of the polarized thermal dust emission at high Galactic latitudes. Here, we specifically study the spatial variability of the dust polarized spectral energy distribution (SED), and its potential impact on the determination of the tensor-to-scalar ratio, r. We use the correlation ratio of the angular power spectra between the 217 and 353 GHz channels as a tracer of these potential variations, computed on different high Galactic latitude regions, ranging from 80% to 20% of the sky. The new insight from Planck data is a departure of the correlation ratio from unity that cannot be attributed to a spurious decorrelation due to the cosmic microwave background, instrumental noise, or instrumental systematics. The effect is marginally detected on each region, but the statistical combination of all the regions gives more than 99% confidence for this variation in polarized dust properties. In addition, we show that the decorrelation increases when there is a decrease in the mean column density of the region of the sky being considered, and we propose a simple power-law empirical model for this dependence, which matches what is seen in the Planck data. We explore the effect that this measured decorrelation has on simulations of the BICEP2-Keck Array/Planck analysis and show that the 2015 constraints from these data still allow a decorrelation between the dust at 150 and 353 GHz that is compatible with our measured value. Finally, using simplified models, we show that either spatial variation of the dust SED or of the dust polarization angle are able to produce decorrelations between 217 and 353 GHz data similar to the values we observe in the data.",

author = "P.A.R Ade and N. Aghanim and J. Aumont and C. Baccigalupi and Ballardini, {Rosa Maria} and A.J. Banday and R.B. Barreiro and N. Bartolo and S. Basak and K. Benabed and Pavel Nasselski and Novikov, {Igor Dmitrievich} and N{\o}rgaard-Nielsen, {Hans Ulrik} and A. Zacchei and P. Vielva and A. Zonca",

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doi = "10.1051/0004-6361/201629164",

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TY - JOUR

T1 - Planck intermediate results. L. Evidence for spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB $B$-mode analysis

AU - Ade, P.A.R

AU - Aghanim, N.

AU - Aumont, J.

AU - Baccigalupi, C.

AU - Ballardini, Rosa Maria

AU - Banday, A.J.

AU - Barreiro, R.B.

AU - Bartolo, N.

AU - Basak, S.

AU - Benabed, K.

AU - Nasselski, Pavel

AU - Novikov, Igor Dmitrievich

AU - Nørgaard-Nielsen, Hans Ulrik

AU - Zacchei, A.

AU - Vielva, P.

AU - Zonca, A.

PY - 2017/3/1

Y1 - 2017/3/1

N2 - The characterization of the Galactic foregrounds has been shown to be the main obstacle in thechallenging quest to detect primordial B-modes in the polarized microwave sky. We make use of the Planck-HFI 2015 data release at high frequencies to place new constraints on the properties of the polarized thermal dust emission at high Galactic latitudes. Here, we specifically study the spatial variability of the dust polarized spectral energy distribution (SED), and its potential impact on the determination of the tensor-to-scalar ratio, r. We use the correlation ratio of the angular power spectra between the 217 and 353 GHz channels as a tracer of these potential variations, computed on different high Galactic latitude regions, ranging from 80% to 20% of the sky. The new insight from Planck data is a departure of the correlation ratio from unity that cannot be attributed to a spurious decorrelation due to the cosmic microwave background, instrumental noise, or instrumental systematics. The effect is marginally detected on each region, but the statistical combination of all the regions gives more than 99% confidence for this variation in polarized dust properties. In addition, we show that the decorrelation increases when there is a decrease in the mean column density of the region of the sky being considered, and we propose a simple power-law empirical model for this dependence, which matches what is seen in the Planck data. We explore the effect that this measured decorrelation has on simulations of the BICEP2-Keck Array/Planck analysis and show that the 2015 constraints from these data still allow a decorrelation between the dust at 150 and 353 GHz that is compatible with our measured value. Finally, using simplified models, we show that either spatial variation of the dust SED or of the dust polarization angle are able to produce decorrelations between 217 and 353 GHz data similar to the values we observe in the data.

AB - The characterization of the Galactic foregrounds has been shown to be the main obstacle in thechallenging quest to detect primordial B-modes in the polarized microwave sky. We make use of the Planck-HFI 2015 data release at high frequencies to place new constraints on the properties of the polarized thermal dust emission at high Galactic latitudes. Here, we specifically study the spatial variability of the dust polarized spectral energy distribution (SED), and its potential impact on the determination of the tensor-to-scalar ratio, r. We use the correlation ratio of the angular power spectra between the 217 and 353 GHz channels as a tracer of these potential variations, computed on different high Galactic latitude regions, ranging from 80% to 20% of the sky. The new insight from Planck data is a departure of the correlation ratio from unity that cannot be attributed to a spurious decorrelation due to the cosmic microwave background, instrumental noise, or instrumental systematics. The effect is marginally detected on each region, but the statistical combination of all the regions gives more than 99% confidence for this variation in polarized dust properties. In addition, we show that the decorrelation increases when there is a decrease in the mean column density of the region of the sky being considered, and we propose a simple power-law empirical model for this dependence, which matches what is seen in the Planck data. We explore the effect that this measured decorrelation has on simulations of the BICEP2-Keck Array/Planck analysis and show that the 2015 constraints from these data still allow a decorrelation between the dust at 150 and 353 GHz that is compatible with our measured value. Finally, using simplified models, we show that either spatial variation of the dust SED or of the dust polarization angle are able to produce decorrelations between 217 and 353 GHz data similar to the values we observe in the data.

U2 - 10.1051/0004-6361/201629164

DO - 10.1051/0004-6361/201629164

M3 - Journal article

SN - 0004-6361

VL - 599

JO - Astronomy & Astrophysics

JF - Astronomy & Astrophysics

M1 - A51

ER -

Planck intermediate results. L. Evidence for spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB $B$-mode analysis

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