164 research outputs found
How Massless Neutrinos Affect the Cosmic Microwave Background Damping Tail
We explore the physical origin and robustness of constraints on the energy
density in relativistic species prior to and during recombination, often
expressed as constraints on an effective number of neutrino species, Neff.
Constraints from current data combination of Wilkinson Microwave Anisotropy
Probe (WMAP) and South Pole Telescope (SPT) are almost entirely due to the
impact of the neutrinos on the expansion rate, and how those changes to the
expansion rate alter the ratio of the photon diffusion scale to the sound
horizon scale at recombination. We demonstrate that very little of the
constraining power comes from the early Integrated Sachs-Wolfe (ISW) effect,
and also provide a first determination of the amplitude of the early ISW
effect. Varying the fraction of baryonic mass in Helium, Yp, also changes the
ratio of damping to sound-horizon scales. We discuss the physical effects that
prevent the resulting near-degeneracy between Neff and Yp from being a complete
one. Examining light element abundance measurements, we see no significant
evidence for evolution of Neff and the baryon-to-photon ratio from the epoch of
big bang nucleosynthesis to decoupling. Finally, we consider measurements of
the distance-redshift relation at low to intermediate redshifts and their
implications for the value of Neff.Comment: 11 pages. Replaced version extends our discussion of origin of
constraints and updates for current data, submitted to PR
Prospective Epidemiological Observations on the Course of the Disease in Fibromyalgia Patients
OBJECTIVES: The aim of the study was to carry out a survey in patients with fibromyalgia (FM), to examine their general health status and work incapacity (disability-pension status), and their views on the effectiveness of therapy received, over a two-year observation period. METHODS: 48 patients diagnosed with FM, according to the American College of Rheumatology (ACR) criteria, took part in the study. At baseline, and on average two years later, the patients underwent clinical investigation (dolorimetry, laboratory diagnostics, medical history taking) and completed the Fibromyalgia questionnaire (Dettmer and Chrostek [1]). RESULTS: 27/48 (56%) patients participated in the two-year follow-up. In general, the patients showed no improvement in their symptoms over the observation period, regardless of the type of therapy they had received. General satisfaction with quality of life improved, as did satisfaction regarding health status and the family situation, although the degree of pain experienced remain unchanged. In comparison with the initial examination, there was no change in either work-capacity or disability-pension status. CONCLUSIONS: The FM patients showed no improvement in pain, despite the many various treatments received over the two-year period. The increase in general satisfaction over the observation period was believed to be the result of patient instruction and education about the disease. To what extent a population of patients with FM would show similar outcomes if they did not receive any instruction/education about their disorder, cannot be ascertained from the present study; and, indeed, the undertaking of a study to investigate this would be ethically questionable. As present, no conclusions can be made regarding the influence of therapy on the primary and secondary costs associated with FM
A measurement of secondary cosmic microwave background anisotropies with two years of South Pole Telescope observations
We present the first three-frequency South Pole Telescope (SPT) cosmic
microwave background (CMB) power spectra. The band powers presented here cover
angular scales 2000 < ell < 9400 in frequency bands centered at 95, 150, and
220 GHz. At these frequencies and angular scales, a combination of the primary
CMB anisotropy, thermal and kinetic Sunyaev-Zel'dovich (SZ) effects, radio
galaxies, and cosmic infrared background (CIB) contributes to the signal. We
combine Planck and SPT data at 220 GHz to constrain the amplitude and shape of
the CIB power spectrum and find strong evidence for non-linear clustering. We
explore the SZ results using a variety of cosmological models for the CMB and
CIB anisotropies and find them to be robust with one exception: allowing for
spatial correlations between the thermal SZ effect and CIB significantly
degrades the SZ constraints. Neglecting this potential correlation, we find the
thermal SZ power at 150 GHz and ell = 3000 to be 3.65 +/- 0.69 muK^2, and set
an upper limit on the kinetic SZ power to be less than 2.8 muK^2 at 95%
confidence. When a correlation between the thermal SZ and CIB is allowed, we
constrain a linear combination of thermal and kinetic SZ power: D_{3000}^{tSZ}
+ 0.5 D_{3000}^{kSZ} = 4.60 +/- 0.63 muK^2, consistent with earlier
measurements. We use the measured thermal SZ power and an analytic, thermal SZ
model calibrated with simulations to determine sigma8 = 0.807 +/- 0.016.
Modeling uncertainties involving the astrophysics of the intracluster medium
rather than the statistical uncertainty in the measured band powers are the
dominant source of uncertainty on sigma8 . We also place an upper limit on the
kinetic SZ power produced by patchy reionization; a companion paper uses these
limits to constrain the reionization history of the Universe.Comment: 25 pages; 14 figures; Submitted to ApJ (Updated to reflect referee
comments
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
A Comparison of Maps and Power Spectra Determined from South Pole Telescope and Planck Data
We study the consistency of 150 GHz data from the South Pole Telescope (SPT)
and 143 GHz data from the Planck satellite over the patch of sky covered by the
SPT-SZ survey. We first visually compare the maps and find that the residuals
appear consistent with noise after accounting for differences in angular
resolution and filtering. We then calculate (1) the cross-spectrum between two
independent halves of SPT data, (2) the cross-spectrum between two independent
halves of Planck data, and (3) the cross-spectrum between SPT and Planck data.
We find the three cross-spectra are well-fit (PTE = 0.30) by the null
hypothesis in which both experiments have measured the same sky map up to a
single free calibration parameter---i.e., we find no evidence for systematic
errors in either data set. As a by-product, we improve the precision of the SPT
calibration by nearly an order of magnitude, from 2.6% to 0.3% in power.
Finally, we compare all three cross-spectra to the full-sky Planck power
spectrum and find marginal evidence for differences between the power spectra
from the SPT-SZ footprint and the full sky. We model these differences as a
power law in spherical harmonic multipole number. The best-fit value of this
tilt is consistent among the three cross-spectra in the SPT-SZ footprint,
implying that the source of this tilt is a sample variance fluctuation in the
SPT-SZ region relative to the full sky. The consistency of cosmological
parameters derived from these datasets is discussed in a companion paper.Comment: 15 pages, 9 figures. Published in The Astrophysical Journal. Current
arxiv version matches published versio
A Comparison of Cosmological Parameters Determined from CMB Temperature Power Spectra from the South Pole Telescope and the Planck Satellite
The Planck cosmic microwave background (CMB) temperature data are best fit
with a LCDM model that is in mild tension with constraints from other
cosmological probes. The South Pole Telescope (SPT) 2540 SPT-SZ
survey offers measurements on sub-degree angular scales (multipoles ) with sufficient precision to use as an independent check of
the Planck data. Here we build on the recent joint analysis of the SPT-SZ and
Planck data in \citet{hou17} by comparing LCDM parameter estimates using the
temperature power spectrum from both data sets in the SPT-SZ survey region. We
also restrict the multipole range used in parameter fitting to focus on modes
measured well by both SPT and Planck, thereby greatly reducing sample variance
as a driver of parameter differences and creating a stringent test for
systematic errors. We find no evidence of systematic errors from such tests.
When we expand the maximum multipole of SPT data used, we see low-significance
shifts in the angular scale of the sound horizon and the physical baryon and
cold dark matter densities, with a resulting trend to higher Hubble constant.
When we compare SPT and Planck data on the SPT-SZ sky patch to Planck full-sky
data but keep the multipole range restricted, we find differences in the
parameters and . We perform further checks, investigating
instrumental effects and modeling assumptions, and we find no evidence that the
effects investigated are responsible for any of the parameter shifts. Taken
together, these tests reveal no evidence for systematic errors in SPT or Planck
data in the overlapping sky coverage and multipole range and, at most, weak
evidence for a breakdown of LCDM or systematic errors influencing either the
Planck data outside the SPT-SZ survey area or the SPT data at .Comment: 14 pages, 7 figures. Updated 1 figure and expanded on the reasoning
for fixing the affect of lensing on the power spectrum instead of varying
Alen
A Direct Measurement of the Linear Bias of Mid-infrared-selected Quasars at z ap 1 Using Cosmic Microwave Background Lensing
We measure the cross-power spectrum of the projected mass density as traced by the convergence of the cosmic microwave background lensing field from the South Pole Telescope (SPT) and a sample of Type 1 and 2 (unobscured and obscured) quasars at langzrang ~ 1 selected with the Wide-field Infrared Survey Explorer, over 2500 deg2. The cross-power spectrum is detected at ≈7σ, and we measure a linear bias b = 1.61 ± 0.22, consistent with clustering analyses. Using an independent lensing map, derived from Planck observations, to measure the cross-spectrum, we find excellent agreement with the SPT analysis. The bias of the combined sample of Type 1 and 2 quasars determined in this work is similar to that previously determined for Type 1 quasars alone; we conclude that obscured and unobscured quasars trace the matter field in a similar way. This result has implications for our understanding of quasar unification and evolution schemes.Peer reviewe
A Measurement of the Cosmic Microwave Background Damping Tail from the 2500-square-degree SPT-SZ survey
We present a measurement of the cosmic microwave background (CMB) temperature
power spectrum using data from the recently completed South Pole Telescope
Sunyaev-Zel'dovich (SPT-SZ) survey. This measurement is made from observations
of 2540 deg of sky with arcminute resolution at GHz, and improves
upon previous measurements using the SPT by tripling the sky area. We report
CMB temperature anisotropy power over the multipole range . We
fit the SPT bandpowers, combined with the seven-year Wilkinson Microwave
Anisotropy Probe (WMAP7) data, with a six-parameter LCDM cosmological model and
find that the two datasets are consistent and well fit by the model. Adding SPT
measurements significantly improves LCDM parameter constraints; in particular,
the constraint on tightens by a factor of 2.7. The impact of
gravitational lensing is detected at , the most significant
detection to date. This sensitivity of the SPT+WMAP7 data to lensing by
large-scale structure at low redshifts allows us to constrain the mean
curvature of the observable universe with CMB data alone to be
. Using the SPT+WMAP7 data, we measure the
spectral index of scalar fluctuations to be in the LCDM
model, a preference for a scale-dependent spectrum with .
The SPT measurement of the CMB damping tail helps break the degeneracy that
exists between the tensor-to-scalar ratio and in large-scale CMB
measurements, leading to an upper limit of (95%,C.L.) in the LCDM+
model. Adding low-redshift measurements of the Hubble constant () and the
baryon acoustic oscillation (BAO) feature to the SPT+WMAP7 data leads to
further improvements. The combination of SPT+WMAP7++BAO constrains
in the LCDM model, a detection of , ... [abridged]Comment: 21 pages, 10 figures. Replaced with version accepted by ApJ. Data
products are available at http://pole.uchicago.edu/public/data/story12
A CMB lensing mass map and its correlation with the cosmic infrared background
We use a temperature map of the cosmic microwave background (CMB) obtained
using the South Pole Telescope at 150 GHz to construct a map of the
gravitational convergence to z ~ 1100, revealing the fluctuations in the
projected mass density. This map shows individual features that are significant
at the ~ 4 sigma level, providing the first image of CMB lensing convergence.
We cross-correlate this map with Herschel/SPIRE maps covering 90 square degrees
at wavelengths of 500, 350, and 250 microns. We show that these
submillimeter-wavelength (submm) maps are strongly correlated with the lensing
convergence map, with detection significances in each of the three submm bands
ranging from 6.7 to 8.8 sigma. We fit the measurement of the cross power
spectrum assuming a simple constant bias model and infer bias factors of
b=1.3-1.8, with a statistical uncertainty of 15%, depending on the assumed
model for the redshift distribution of the dusty galaxies that are contributing
to the Herschel/SPIRE maps.Comment: 5 pages, 3 figures, to be submitted to ApJ
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