631 research outputs found
Consistency of cosmic microwave background temperature measurements in three frequency bands in the 2500-square-degree SPT-SZ survey
We present an internal consistency test of South Pole Telescope (SPT)
measurements of the cosmic microwave background (CMB) temperature anisotropy
using three-band data from the SPT-SZ survey. These measurements are made from
observations of ~2500 deg^2 of sky in three frequency bands centered at 95,
150, and 220 GHz. We combine the information from these three bands into six
semi-independent estimates of the CMB power spectrum (three single-frequency
power spectra and three cross-frequency spectra) over the multipole range 650 <
l < 3000. We subtract an estimate of foreground power from each power spectrum
and evaluate the consistency among the resulting CMB-only spectra. We determine
that the six foreground-cleaned power spectra are consistent with the null
hypothesis, in which the six cleaned spectra contain only CMB power and noise.
A fit of the data to this model results in a chi-squared value of 236.3 for 235
degrees of freedom, and the probability to exceed this chi-squared value is
46%.Comment: 21 pages, 4 figures, current version matches version published in
JCA
Recommended from our members
Ignition Capsules with Aerogel-Supported Liquid DT Fuel For The National Ignition Facility
For high repetition-rate fusion power plant applications, capsules with aerogel-supported liquid DT fuel can have much reduced fill time compared to {beta}-layering a solid DT fuel layer. The melting point of liquid DT can be lowered once liquid DT is embedded in an aerogel matrix, and the DT vapor density is consequently closer to the desired density for optimal capsule design requirement. We present design for NIF-scale aerogel-filled capsules based on 1-D and 2-D simulations. An optimal configuration is obtained when the outer radius is increased until the clean fuel fraction is within 65-75% at peak velocity. A scan (in ablator and fuel thickness parameter space) is used to optimize the capsule configurations. The optimized aerogel-filled capsule has good low-mode robustness and acceptable high-mode mix
CMB Polarization B-mode Delensing with SPTpol and Herschel
We present a demonstration of delensing the observed cosmic microwave
background (CMB) B-mode polarization anisotropy. This process of reducing the
gravitational-lensing generated B-mode component will become increasingly
important for improving searches for the B modes produced by primordial
gravitational waves. In this work, we delens B-mode maps constructed from
multi-frequency SPTpol observations of a 90 deg patch of sky by subtracting
a B-mode template constructed from two inputs: SPTpol E-mode maps and a lensing
potential map estimated from the map of the
CIB. We find that our delensing procedure reduces the measured B-mode power
spectrum by 28% in the multipole range ; this is shown to be
consistent with expectations from theory and simulations and to be robust
against systematics. The null hypothesis of no delensing is rejected at . Furthermore, we build and use a suite of realistic simulations to
study the general properties of the delensing process and find that the
delensing efficiency achieved in this work is limited primarily by the noise in
the lensing potential map. We demonstrate the importance of including realistic
experimental non-idealities in the delensing forecasts used to inform
instrument and survey-strategy planning of upcoming lower-noise experiments,
such as CMB-S4.Comment: 17 pages, 10 figures. Comments are welcome
Measurements of the Temperature and E-Mode Polarization of the CMB from 500 Square Degrees of SPTpol Data
We present measurements of the -mode polarization angular auto-power
spectrum () and temperature--mode cross-power spectrum () of the
cosmic microwave background (CMB) using 150 GHz data from three seasons of
SPTpol observations. We report the power spectra over the spherical harmonic
multipole range , and detect nine acoustic peaks in the
spectrum with high signal-to-noise ratio. These measurements are the most
sensitive to date of the and power spectra at and , respectively. The observations cover 500 deg, a fivefold increase
in area compared to previous SPTpol analyses, which increases our sensitivity
to the photon diffusion damping tail of the CMB power spectra enabling tighter
constraints on \LCDM model extensions. After masking all sources with
unpolarized flux mJy we place a 95% confidence upper limit on residual
polarized point-source power of at , suggesting that the damping tail
dominates foregrounds to at least with modest source masking. We
find that the SPTpol dataset is in mild tension with the model
(), and different data splits prefer parameter values that differ
at the level. When fitting SPTpol data at we
find cosmological parameter constraints consistent with those for
temperature. Including SPTpol data at results in a preference for
a higher value of the expansion rate (H_0 = 71.3 \pm
2.1\,\mbox{km}\,s^{-1}\mbox{Mpc}^{-1} ) and a lower value for present-day
density fluctuations ().Comment: Updated to match version accepted to ApJ. 34 pages, 17 figures, 6
table
CMB-S4 Science Book, First Edition
This book lays out the scientific goals to be addressed by the
next-generation ground-based cosmic microwave background experiment, CMB-S4,
envisioned to consist of dedicated telescopes at the South Pole, the high
Chilean Atacama plateau and possibly a northern hemisphere site, all equipped
with new superconducting cameras. CMB-S4 will dramatically advance cosmological
studies by crossing critical thresholds in the search for the B-mode
polarization signature of primordial gravitational waves, in the determination
of the number and masses of the neutrinos, in the search for evidence of new
light relics, in constraining the nature of dark energy, and in testing general
relativity on large scales
Charmless hadronic decays and new physics effects in the general two-Higgs doublet models
Based on the low-energy effective Hamiltonian with the generalized
factorization, we calculate the new physics contributions to the branching
ratios of the two-body charmless hadronic decays of and mesons
induced by the new gluonic and electroweak charged-Higgs penguin diagrams in
the general two-Higgs doublet models (models I, II and III). Within the
considered parameter space, we find that: (a) the new physics effects from new
gluonic penguin diagrams strongly dominate over those from the new -
and - penguin diagrams; (b) in models I and II, new physics contributions
to most studied B meson decay channels are rather small in size: from -15% to
20%; (c) in model III, however, the new physics enhancements to the
penguin-dominated decay modes can be significant, , and
therefore are measurable in forthcoming high precision B experiments; (d) the
new physics enhancements to ratios {\cal B}(B \to K \etap) are significant in
model III, , and hence provide a simple and plausible new
physics interpretation for the observed unexpectedly large B \to K \etap
decay rates; (e) the theoretical predictions for and
in model III are still consistent with the data
within errors; (f) the significant new physics enhancements to the
branching ratios of and decays are helpful to improve the
agreement between the data and the theoretical predictions; (g) the theoretical
predictions of in the 2HDM's are generally
consistent with experimental measurements and upper limits ()Comment: 55 pages, Latex file, 17 PS and EPS figures. With minor corrections,
final version to be published in Phys.Rev. D. Repot-no: PKU-TH-2000-4
Maps of the Southern Millimeter-wave Sky from Combined 2500 deg SPT-SZ and Planck Temperature Data
We present three maps of the millimeter-wave sky created by combining data
from the South Pole Telescope (SPT) and the Planck satellite. We use data from
the SPT-SZ survey, a survey of 2540 deg of the the sky with arcminute
resolution in three bands centered at 95, 150, and 220 GHz, and the
full-mission Planck temperature data in the 100, 143, and 217 GHz bands. A
linear combination of the SPT-SZ and Planck data is computed in spherical
harmonic space, with weights derived from the noise of both instruments. This
weighting scheme results in Planck data providing most of the
large-angular-scale information in the combined maps, with the smaller-scale
information coming from SPT-SZ data. A number of tests have been done on the
maps. We find their angular power spectra to agree very well with theoretically
predicted spectra and previously published results.Comment: 21 pages, 12 figure
Homocysteine, B vitamins, and the incidence of dementia and cognitive impairment: results from the Sacramento Area Latino Study on Aging
http://deepblue.lib.umich.edu/bitstream/2027.42/55438/1/Haan M, Homocysteine, b vitamins, and the incidence of dementia, 2007.pd
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