Galactic foreground contributions to the 5-year Wilkinson Microwave Anisotropy Probe maps

Macellari, N.; Pierpaoli, E.; Dickinson, C.; Vaillancourt, John E.

doi:10.1111/j.1365-2966.2011.19542.x

Cited by 62 publications

(70 citation statements)

References 73 publications

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“…However, Battistelli et al (2015) argue that a large fraction of this signal could be residual synchrotron radiation, leaving little or no polarized AME. There have been very few attempts to constrain the polarization from the large-scale diffuse AME; Kogut et al (2007) find that AME accounts for less than 1% of the total polarized signal, while Macellari et al (2011) placed a limit of <5% based on template fitting of WMAP data. Planck Collaboration Int.…”

Section: Limits On Ame Polarizationmentioning

confidence: 99%

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Planck2015 results

Ade

Aghanim

Alves

et al. 2016

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163

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We discuss the Galactic foreground emission between 20 and 100 GHz based on observations by Planck and WMAP. The total intensity in this part of the spectrum is dominated by free-free and spinning dust emission, whereas the polarized intensity is dominated by synchrotron emission. The Commander component-separation tool has been used to separate the various astrophysical processes in total intensity. Comparison with radio recombination line templates verifies the recovery of the free-free emission along the Galactic plane. Comparison of the high-latitude Hα emission with our free-free map shows residuals that correlate with dust optical depth, consistent with a fraction (≈30%) of Hα having been scattered by high-latitude dust. We highlight a number of diffuse spinning dust morphological features at high latitude. There is substantial spatial variation in the spinning dust spectrum, with the emission peak (in I ν ) ranging from below 20 GHz to more than 50 GHz. There is a strong tendency for the spinning dust component near many prominent H ii regions to have a higher peak frequency, suggesting that this increase in peak frequency is associated with dust in the photo-dissociation regions around the nebulae. The emissivity of spinning dust in these diffuse regions is of the same order as previous detections in the literature. Over the entire sky, the Commander solution finds more anomalous microwave emission (AME) than the WMAP component maps, at the expense of synchrotron and free-free emission. This can be explained by the difficulty in separating multiple broadband components with a limited number of frequency maps. Future surveys, particularly at 5-20 GHz, will greatly improve the separation by constraining the synchrotron spectrum. We combine Planck and WMAP data to make the highest signal-to-noise ratio maps yet of the intensity of the all-sky polarized synchrotron emission at frequencies above a few GHz. Most of the high-latitude polarized emission is associated with distinct large-scale loops and spurs, and we re-discuss their structure. We argue that nearly all the emission at 40 • > l > −90 • is part of the Loop I structure, and show that the emission extends much further in to the southern Galactic hemisphere than previously recognised, giving Loop I an ovoid rather than circular outline. However, it does not continue as far as the "Fermi bubble/microwave haze", making it less probable that these are part of the same structure. We identify a number of new faint features in the polarized sky, including a dearth of polarized synchrotron emission directly correlated with a narrow, roughly 20 • long filament seen in Hα at high Galactic latitude. Finally, we look for evidence of polarized AME, however many AME regions are significantly contaminated by polarized synchrotron emission, and we find a 2σ upper limit of 1.6% in the Perseus region.

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Section: Limits On Ame Polarizationmentioning

confidence: 99%

“…The polarization of AME is of great interest to CMB cosmologists, since a significant level of polarization could hamper measurements of B modes. Current measurements place upper limits on the polarization of AME at a few per cent or below Macellari et al 2011;Rubiño-Martín et al 2012a). …”

Section: Introductionmentioning

confidence: 99%

Planck2015 results

Ade

Aghanim

Alves

et al. 2016

A&A

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163

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“…Since its specific intensity scaling with frequency follows a power law with a spectral index close to −3 (Gold et al 2011;Macellari et al 2011;Fuskeland et al 2014), synchrotron polarized emission is expected to be subdominant in the Planck HFI channels in general and negligible at 353 GHz (Tucci et al 2005;Dunkley et al 2009a;Gold et al 2011;Fauvet et al 2011;Fuskeland et al 2014;Planck Collaboration Int. XXII 2015).…”

Section: Synchrotron Emissionmentioning

confidence: 99%

Planckintermediate results

Adam¹,

Ade²,

Aghanim³

et al. 2016

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187

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The polarized thermal emission from diffuse Galactic dust is the main foreground present in measurements of the polarization of the cosmic microwave background (CMB) at frequencies above 100 GHz. In this paper we exploit the uniqueness of the Planck HFI polarization data from 100 to 353 GHz to measure the polarized dust angular power spectra C EE and C BB over the multipole range 40 < < 600 well away from the Galactic plane. These measurements will bring new insights into interstellar dust physics and allow a precise determination of the level of contamination for CMB polarization experiments. Despite the non-Gaussian and anisotropic nature of Galactic dust, we show that general statistical properties of the emission can be characterized accurately over large fractions of the sky using angular power spectra. The polarization power spectra of the dust are well described by power laws in multipole, C ∝ α , with exponents α EE,BB = −2.42 ± 0.02. The amplitudes of the polarization power spectra vary with the average brightness in a way similar to the intensity power spectra. The frequency dependence of the dust polarization spectra is consistent with modified blackbody emission with β d = 1.59 and T d = 19.6 K down to the lowest Planck HFI frequencies. We find a systematic difference between the amplitudes of the Galactic B-and E-modes, C BB /C EE = 0.5. We verify that these general properties are preserved towards high Galactic latitudes with low dust column densities. We show that even in the faintest dust-emitting regions there are no "clean" windows in the sky where primordial CMB B-mode polarization measurements could be made without subtraction of foreground emission. Finally, we investigate the level of dust polarization in the specific field recently targeted by the BICEP2 experiment. Extrapolation of the Planck 353 GHz data to 150 GHz gives a dust power D BB ≡ ( + 1)C BB /(2π) of 1.32 × 10 −2 µK 2 CMB over the multipole range of the primordial recombination bump (40 < < 120); the statistical uncertainty is ±0.29 × 10 −2 µK 2 CMB and there is an additional uncertainty (+0.28, −0.24) × 10 −2 µK 2 CMB from the extrapolation. This level is the same magnitude as reported by BICEP2 over this range, which highlights the need for assessment of the polarized dust signal even in the cleanest windows of the sky.

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“…This is neglected in the current version of the model. The Thomson scattered free-free light is expected to be small (a few percent or likely less, Page et al 2007;Gold et al 2011;Macellari et al 2011), with a maximum of about 10% on the edge of bright H ii regions (e.g., Rybicki & Lightman 1979).…”

Section: Polarisation Of Other Ism Emissionmentioning

confidence: 99%

The pre-launchPlanckSky Model: a model of sky emission at submillimetre to centimetre wavelengths

Delabrouille

Betoule

Melin

et al. 2013

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211

231

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We present the Planck Sky Model (PSM), a parametric model for generating all-sky, few arcminute resolution maps of sky emission at submillimetre to centimetre wavelengths, in both intensity and polarisation. Several options are implemented to model the cosmic microwave background, Galactic diffuse emission (synchrotron, free-free, thermal and spinning dust, CO lines), Galactic H ii regions, extragalactic radio sources, dusty galaxies, and thermal and kinetic Sunyaev-Zeldovich signals from clusters of galaxies. Each component is simulated by means of educated interpolations/extrapolations of data sets available at the time of the launch of the Planck mission, complemented by state-of-the-art models of the emission. Distinctive features of the simulations are spatially varying spectral properties of synchrotron and dust; different spectral parameters for each point source; modelling of the clustering properties of extragalactic sources and of the power spectrum of fluctuations in the cosmic infrared background. The PSM enables the production of random realisations of the sky emission, constrained to match observational data within their uncertainties. It is implemented in a software package that is regularly updated with incoming information from observations. The model is expected to serve as a useful tool for optimising planned microwave and sub-millimetre surveys and testing data processing and analysis pipelines. It is, in particular, used to develop and validate data analysis pipelines within the Planck collaboration. A version of the software that can be used for simulating the observations for a variety of experiments is made available on a dedicated website.

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Galactic foreground contributions to the 5-year Wilkinson Microwave Anisotropy Probe maps

Cited by 62 publications

References 73 publications

Planck2015 results

Planck2015 results

Planckintermediate results

The pre-launchPlanckSky Model: a model of sky emission at submillimetre to centimetre wavelengths

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