QUaD: A HIGH-RESOLUTION COSMIC MICROWAVE BACKGROUND POLARIMETER

Hinderks, J.; Ade, Peter A. R.; Bock, J. J.; Bowden, M.; Brown, Michael L.; Cahill, G.; Carlstrom, J. E.; Castro, Paulo Francisco de; Church, S.; Culverhouse, T.; Friedman, Robert; Ganga, K.; Gear, Walter Kieran; Gupta, S.; Harris, J. W.; Haynes, V.; Keating, Brian; Kovac, J. M.; Kirby, Elizabeth D.; Lange, A. E.; Leitch, E. M.; Mallie, O. E.; Melhuish, S. J.; Memari, Y.; Murphy, John A.; Orlando, A.; Schwarz, R.; O'Sullivan, Créidhe M.; Piccirillo, L.; Pryke, C.; Rajguru, N.; Rusholme, B.; Taylor, Andy; Thompson, K. L.; Tucker, C.; Turner, A. H.; Wu, Emily; Zemcov, Michael

doi:10.1088/0004-637x/692/2/1221

Cited by 53 publications

(48 citation statements)

References 34 publications

(36 reference statements)

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“…The average auto spectra over all PSB pairs in each frequency band are plotted in Figure 19, with the detector voltages converted to CMB temperature differences. The NETs are consistent with expectations, and are comparable to the best achieved in other ground-based experiments (Runyan et al 2003;Hinderks et al 2009). Before differencing, the timestreams show significant atmospheric noise below 1 Hz.…”

Section: Properties Of Noise: Spectra and Covariancesupporting

confidence: 90%

Characterization of the Bicep Telescope for High-Precision Cosmic Microwave Background Polarimetry

Takahashi¹,

Ade²,

Barkats³

et al. 2010

ApJ

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The Background Imaging of Cosmic Extragalactic Polarization (Bicep) experiment was designed specifically to search for the signature of inflationary gravitational waves in the polarization of the cosmic microwave background (CMB). Using a novel small-aperture refractor and 49 pairs of polarization-sensitive bolometers, Bicep has completed three years of successful observations at the South Pole beginning in 2006 February. To constrain the amplitude of the inflationary B-mode polarization, which is expected to be at least 7 orders of magnitude fainter than the 3 K CMB intensity, precise control of systematic effects is essential. This paper describes the characterization of potential systematic errors for the Bicep experiment, supplementing a companion paper on the initial cosmological results. Using the analysis pipelines for the experiment, we have simulated the impact of systematic errors on the B-mode polarization measurement. Guided by these simulations, we have established benchmarks for the characterization of critical instrumental properties including bolometer relative gains, beam mismatch, polarization orientation, telescope pointing, sidelobes, thermal stability, and timestream noise model. A comparison of the benchmarks with the measured values shows that we have characterized the instrument adequately to ensure that systematic errors do not limit Bicep's two-year results, and identifies which future refinements are likely necessary to probe inflationary B-mode polarization down to levels below a tensor-to-scalar ratio r = 0.1.

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Section: Properties Of Noise: Spectra and Covariancesupporting

confidence: 90%

Characterization of the Bicep Telescope for High-Precision Cosmic Microwave Background Polarimetry

Takahashi¹,

Ade²,

Barkats³

et al. 2010

ApJ

Self Cite

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“…Over the past years, CMB polarization has been measured by several experiments and is being measured by the Planck surveyor Leitch et al 2002;Pryke et al 2002a,b Halverson et al 2002Leitch et al 2005;Ade & et al 2008;Pryke & et al 2009;Hinderks et al 2009;Brown & et al 2009;The Planck Collaboration 2006). CMB polarization pattern may be considered as the sum of gradient-like E mode and curllike B mode (Zaldarriaga & Seljak 1997;Kamionkowski et al 1997).…”

Section: Introductionmentioning

confidence: 99%

E/B decomposition of CMB polarization pattern of incomplete sky: a pixel space approach

Kim¹,

Naselsky²

2010

A&A

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CMB polarization pattern may be decomposed into gradient-like (E) and curl-like (B) mode, which provide invaluable information respectively. We have investigated E/B decomposition in pixel space. We find E/B mixing due to incomplete sky is localized in pixel-space, and negligible in the regions far away from the masked area. By estimating the expected local leakage power, we have diagnosed ambiguous pixels. Our criteria for ambiguous pixels (i.e. r c ) is associated with the tensor-to-scalar ratio of B mode power spectrum, which the leakage power is comparable to. By setting r c to a lower value, we may reduce leakage level, but reduce sky fraction at the same time. Therefore, we have solved ∂ΔC l /∂r c = 0, and obtained the optimal r c , which minimizes the estimation uncertainty, given a foreground mask and noise level. We have applied our method to a simulated map blocked by a foreground (diffuse + point source) mask. Our simulation shows leakage power is smaller than primordial (i.e. unlensed) B mode power spectrum of tensor-to-scalar ratio r ∼ 1 × 10 −3 at wide range of multipoles (50 l 2000), while allowing us to retain sky fraction ∼0.48.

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“…Over the past few years, CMB polarization has been measured by several experiments, and is being measured by the Planck surveyor Leitch et al 2002;Pryke et al 2002a;Halverson et al 2002;Pryke et al 2002b;Leitch et al 2005;Ade & et al 2008;Pryke & et al 2009;Hinderks et al 2009;Brown & et al 2009;The Planck Collaboration 2006). Using the general properties of symmetric trace-free tensors, we may decompose CMB polarization into the gradient-like E mode and the curl-like B mode (Kamionkowski et al 1997;Zaldarriaga & Seljak 1997).…”

Section: Introductionmentioning

confidence: 99%

How to make a clean separation between CMB E and B modes with proper foreground masking

Kim¹

2011

A&A

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We investigate the E/B decomposition of CMB polarization on a masked sky. In real space, operators of E and B mode decomposition involve only differentials of CMB polarization. We may, therefore in principle, perform a clean E/B decomposition from incomplete sky data. Since it is impractical to apply second derivatives to observation data, we usually rely on spherical harmonic transformation and inverse transformation, instead of using real-space operators. In spherical harmonic representation, jump discontinuities in a cut sky produces Gibbs phenomenon, unless a spherical harmonic expansion is made up to an infinitely high multipole. By smoothing a foreground mask, we may suppress the Gibbs phenomenon effectively in a similar manner to apodization of a foreground mask discussed in other works. However, we incur foreground contamination by smoothing a foreground mask, because zero-value pixels in the original mask may be rendered non-zero by the smoothing process. In this work, we investigate an optimal foreground mask, which ensures proper foreground masking and suppresses Gibbs phenomenon. We apply our method to a simulated map of the pixel resolution comparable to the Planck satellite. The simulation shows that the leakage power is lower than unlensed CMB B mode power spectrum of tensor-to-scalar ratio r ∼ 1 × 10 −7 . We compare the result with that of the original mask. We find that the leakage power is reduced by a factor of 10 6 ∼ 10 9 at the cost of a sky fraction 0.07, and that that the enhancement is highest at lowest multipoles. We confirm that all the zero-value pixels in the original mask remain zero in our mask. The application of this method to the Planck data will improve the detectability of primordial tensor perturbation.

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QUaD: A HIGH-RESOLUTION COSMIC MICROWAVE BACKGROUND POLARIMETER

Cited by 53 publications

References 34 publications

Characterization of the Bicep Telescope for High-Precision Cosmic Microwave Background Polarimetry

Characterization of the Bicep Telescope for High-Precision Cosmic Microwave Background Polarimetry

E/B decomposition of CMB polarization pattern of incomplete sky: a pixel space approach

How to make a clean separation between CMB E and B modes with proper foreground masking

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