The BICEP2 CMB polarization experiment

Ogburn, R. W.; Ade, Peter A. R.; Aikin, R. W.; Amiri, M.; Benton, S. J.; Bock, J. J.; Bonetti, J. A.; Brevik, J. A.; Burger, B.; Dowell, C. D.; Duband, L.; Filippini, J. P.; Golwala, S. R.; Halpern, M.; Hasselfield, Matthew; Hilton, G. C.; Hristov, V. V.; Irwin, K. D.; Kaufman, Jon; Keating, Brian; Kovac, J. M.; Kuo, Chao-Lin; Lange, A. E.; Leitch, E. M.; Netterfield, C. B.; Nguyen, Hien; Orlando, A.; Pryke, C.; Reintsema, C. D.; Richter, Sonja; Ruhl, J. E.; Runyan, M. C.; Sheehy, C. D.; Staniszewski, Z.; Stokes, S.; Sudiwala, R.; Teply, G. P.; Tolan, J. E.; Turner, Anthony; Wilson, P.; Wong, C. L.

doi:10.1117/12.857864

Cited by 26 publications

(10 citation statements)

References 21 publications

(26 reference statements)

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“…The arrays are read out using a time-domain SQUID multiplexer system [23,24]. Four such focal planes are currently in operation at the South Pole, as part of the Bicep2 instrument [25] and the Keck array [26].…”

Section: Descriptionmentioning

confidence: 99%

SPIDER: probing the early Universe with a suborbital polarimeter

Fraisse

Ade

Amiri

et al. 2013

J. Cosmol. Astropart. Phys.

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We evaluate the ability of Spider, a balloon-borne polarimeter, to detect a divergence-free polarization pattern (B-modes) in the cosmic microwave background (CMB). In the inflationary scenario, the amplitude of this signal is proportional to that of the primordial scalar perturbations through the tensor-to-scalar ratio r. We show that the expected level of systematic error in the Spider instrument is significantly below the amplitude of an interesting cosmological signal with r = 0.03. We present a scanning strategy that enables us to minimize uncertainty in the reconstruction of the Stokes parameters used to characterize the CMB, while accessing a relatively wide range of angular scales. Evaluating the amplitude of the polarized Galactic emission in the Spider field, we conclude that the polarized emission from interstellar dust is as bright or brighter than the cosmological signal at all Spider frequencies (90 GHz, 150 GHz, and 280 GHz), a situation similar to that found in the "Southern Hole." We show that two ∼ 20-day flights of the Spider instrument can constrain the amplitude of the B-mode signal to r < 0.03 (99% CL) even when foreground contamination is taken into account. In the absence of foregrounds, the same limit can be reached after one 20-day flight.

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Section: Descriptionmentioning

confidence: 99%

SPIDER: probing the early Universe with a suborbital polarimeter

Fraisse

Ade

Amiri

et al. 2013

J. Cosmol. Astropart. Phys.

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“…Many new techniques also promise future measurements of these primordial GWs. Firstly, it has been shown that such a GW background would leave a detectable signature in the polarization of the cosmic microwave background (CMB) [5,6], which will be measured by many current and future observational efforts [7][8][9][10][11][12][13][14][15][16]. The planned spacebased interferometer LISA will also set limits on the primordial stochastic gravitational wave background (SGWB) [17].…”

Section: A the Stochastic Gravitational Wave Backgroundmentioning

confidence: 99%

Astrometric effects of a stochastic gravitational wave background

2011

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A stochastic gravitational wave background causes the apparent positions of distant sources to fluctuate, with angular deflections of order the characteristic strain amplitude of the gravitational waves. These fluctuations may be detectable with high precision astrometry, as first suggested by Braginsky et al. in 1990. Several researchers have made order of magnitude estimates of the upper limits obtainable on the gravitational wave spectrum Ωgw(f ), at frequencies of order f ∼ 1 yr −1 , both for the future space-based optical interferometry missions GAIA and SIM, and for VLBI interferometry in radio wavelengths with the SKA. For GAIA, tracking N ∼ 10 6 quasars over a time of T ∼ 1 yr with an angular accuracy of ∆θ ∼ 10µas would yield a sensitivity level of Ωgw ∼ (∆θ) 2 /(N T 2 H 2 0 ) ∼ 10 −6 , which would be comparable with pulsar timing. In this paper we take a first step toward firming up these estimates by computing in detail the statistical properties of the angular deflections caused by a stochastic background. We compute analytically the two point correlation function of the deflections on the sphere, and the spectrum as a function of frequency and angular scale. The fluctuations are concentrated at low frequencies (for a scale invariant stochastic background), and at large angular scales, starting with the quadrupole. The magnetic-type and electric-type pieces of the fluctuations have equal amounts of power.

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“…Because measurements of temperature anisotropies at small angular scales become dominated by the effects of hot gas in galaxy clusters and clustered infrared-emitting galaxies [23], more precise measurements of polarization power spectra should be able to push cosmic string constraints to well below what is possible with temperature information alone. Indeed, several ongoing and upcoming projects (Planck [24], COrE [25], ACTPol [26], SPT-Pol [27], BICEP2/Keck [28,29], POLARBEAR [30], and SPIDER [31], among others) will soon measure CMB polarization to unprecedented accuracy, and so in the near future we will be able to obtain strict limits on the cosmic string content of the Universe.…”

Section: Introductionmentioning

confidence: 99%

Predicted constraints on cosmic string tension from Planck and future CMB polarization measurements

2011

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We perform a Fisher matrix calculation of the predicted uncertainties on estimates of the cosmic string tension G from upcoming observational data (namely, cosmic microwave background power spectra from the Planck satellite and an idealized future polarization experiment). We employ simulations that are more general than others commonly used in the literature, leaving the mean velocity of strings, correlation length of the string network, and wiggliness (which parametrizes smaller-scale structure along the strings) as free parameters that can be observationally measured. In a new code, STRINGFAST, we implement a method for efficient computation of the C ' spectra induced by a network of strings, which is fast enough to be used in Markov Chain Monte Carlo analyses of future data. Performing a calculation with the string parameters left free results in projected constraints on G that are larger than those obtained by fixing their values a priori, typically by a factor of $2-7. We also find that, if G is equal to the current observational maximum, Planck will be able to make a confident detection of strings. However, if G is 2 orders of magnitude smaller, even a perfect, lensing-free measurement of polarization power spectra will not be able to detect a nonzero string tension at better than 2 confidence.

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The BICEP2 CMB polarization experiment

Cited by 26 publications

References 21 publications

SPIDER: probing the early Universe with a suborbital polarimeter

SPIDER: probing the early Universe with a suborbital polarimeter

Astrometric effects of a stochastic gravitational wave background

Predicted constraints on cosmic string tension from Planck and future CMB polarization measurements

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