Sharpening the Precision of the Sunyaev-Zel'dovich Power Spectrum

Shaw, L.; Zahn, O.; Holder, G. P.; Doré, O.

doi:10.1088/0004-637x/702/1/368

Cited by 52 publications

(71 citation statements)

References 51 publications

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“…the most non-Gaussian features) from the power spectrum improves the errors on Ω m and σ 8 , the errors being smallest for an optimal threshold ν th,opt ≈ 6. Although the counter-intuitive increase in the performance that we observe when discarding the resolved part of the data is not so surprising, since the impact of non-Gaussianities on the power spectrum is lowered (Shaw et al 2009 observe a similar trend for Sunyaev-Zel'dovich clusters), we should note here that it could be exacerbated if our analysis is close to the Fisher matrices formalism's limits. Moreover, there may be an optimal weighting scheme that would both allow for the signal in the resolved part and minimize its non-Gaussian errors.…”

Section: Resultsmentioning

confidence: 52%

Optimal Capture of Non-Gaussianity in Weak-Lensing Surveys: Power Spectrum, Bispectrum, and Halo Counts

Bergé

Amara

Réfrégier

2010

ApJ

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We compare the efficiency of weak lensing-selected galaxy clusters counts and of the weak lensing bispectrum at capturing non-Gaussian features in the dark matter distribution. We use the halo model to compute the weak lensing power spectrum, the bispectrum and the expected number of detected clusters, and derive constraints on cosmological parameters for a large, low systematic weak lensing survey, by focusing on the Ω m -σ 8 plane and on the dark energy equation of state. We separate the power spectrum into the resolved and the unresolved parts of the data, the resolved part being defined as detected clusters, and the unresolved part as the rest of the field. We consider four kinds of clusters counts, taking into account different amount of information : signal-to-noise ratio peak counts; counts as a function of clusters' mass; counts as a function of clusters' redshift; and counts as a function of clusters' mass and redshift. We show that when combined with the power spectrum, those four kinds of counts provide similar constraints, thus allowing one to perform the most direct counts, signalto-noise peaks counts, and get percent level constraints on cosmological parameters. We show that the weak lensing bispectrum gives constraints comparable to those given by the power spectrum and captures non-Gaussian features as well as clusters counts, its combination with the power spectrum giving errors on cosmological parameters that are similar to, if not marginally smaller than, those obtained when combining the power spectrum with cluster counts. We finally note that in order to reach its potential, the weak lensing bispectrum must be computed using all triangle configurations, as equilateral triangles alone do not provide useful information. The appendices summarize the halo model, and the way the power spectrum and bispectrum are computed in this framework.

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Section: Resultsmentioning

confidence: 52%

Optimal Capture of Non-Gaussianity in Weak-Lensing Surveys: Power Spectrum, Bispectrum, and Halo Counts

Bergé

Amara

Réfrégier

2010

ApJ

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“…As the predictions for the SZ power spectrum available today (see, e.g., Shaw et al 2009;Sehgal et al 2010, and references therein) are similar to the prediction of Komatsu & Seljak (2002) (for example, Lueker et al 2010 found A SZ = 0.55 ± 0.21 for the prediction of Sehgal et al 2010, which is based on the gas model of Bode et al 2009), a plausible explanation for a lowerthan-expected A SZ is a lower-than-expected gas pressure. Arnaud et al (2007) find that the X-ray observed integrated pressure enclosed within r 500 , Y X ≡ M gas,500 T X , for a given M 500 is about a factor of 0.75 times the prediction from the Cooling+SF simulation of Nagai et al (2007).…”

Section: Discussionmentioning

confidence: 68%

SEVEN-YEARWILKINSON MICROWAVE ANISOTROPY PROBE(WMAP) OBSERVATIONS: COSMOLOGICAL INTERPRETATION

Komatsu¹,

Smith²,

Dunkley³

et al. 2011

ApJS

7,635

472

6,429

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The combination of seven-year data from WMAP and improved astrophysical data rigorously tests the standard cosmological model and places new constraints on its basic parameters and extensions. By combining the WMAP data with the latest distance measurements from the baryon acoustic oscillations (BAO) in the distribution of galaxies and the Hubble constant (H 0 ) measurement, we determine the parameters of the simplest six-parameter ΛCDM model. The power-law index of the primordial power spectrum is n s = 0.968 ± 0.012 (68% CL) for this data combination, a measurement that excludes the Harrison-Zel'dovich-Peebles spectrum by 99.5% CL. The other parameters, including those beyond the minimal set, are also consistent with, and improved from, the five-year results. We find no convincing deviations from the minimal model. The seven-year temperature power spectrum gives a better determination of the third acoustic peak, which results in a better determination of the redshift of the matter-radiation equality epoch. Notable examples of improved parameters are the total mass of neutrinos, m ν < 0.58 eV (95% CL), and the effective number of neutrino species, N eff = 4.34 +0.86 −0.88 (68% CL), which benefit from better determinations of the third peak and H 0 . The limit on a constant dark energy equation of state parameter from WMAP+BAO+H 0 , without high-redshift Type Ia supernovae, is w = −1.10 ± 0.14 (68% CL). We detect the effect of primordial helium on the temperature power spectrum and provide a new test of big bang nucleosynthesis by measuring Y p = 0.326 ± 0.075 (68% CL). We detect, and show on the map for the first time, the tangential and radial polarization patterns around hot and cold spots of temperature fluctuations, an important test of physical processes at z = 1090 and the dominance of adiabatic scalar fluctuations. The seven-year polarization data have significantly improved: we now detect the temperature-E-mode polarization cross power spectrum at 21σ , compared with 13σ from the five-year data. With the seven-year temperature-B-mode cross power spectrum, the limit on a rotation of the polarization plane due to potential parity-violating effects has improved by 38% to Δα = −1.• 1 ± 1.• 4(statistical) ± 1.• 5(systematic) (68% CL). We report significant detections of the Sunyaev-Zel'dovich (SZ) effect at the locations of known clusters of galaxies. The measured SZ signal agrees well with the expected signal from the X-ray data on a cluster-by-cluster basis. However, it is a factor of 0.5-0.7 times the predictions from "universal profile" of Arnaud et al., analytical models, and hydrodynamical simulations. We find, for the first time in the SZ effect, a significant difference between the cooling-flow and non-cooling-flow clusters (or relaxed and non-relaxed clusters), which can explain some of the discrepancy. This lower amplitude is consistent with the lower-than-theoretically expected SZ power spectrum recently measured by the South Pole Telescope Collaboration.

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“…By combining SPT survey maps at 150 and 220 GHz to minimize astrophysical foreground signals, Lueker et al (2010) were able to isolate and detect SZ power (kinetic plus thermal) at 2.6σ . The measured amplitude at = 3000 was 4.2 ± 1.5 μK 2 , significantly below that predicted by halo model calculations (Komatsu & Seljak 2002) or simulations (White et al 2002;Shaw et al 2009;Sehgal et al 2010), assuming WMAP7 cosmological parameters. The significantly lower-than-predicted signal could be explained by a lower value of σ 8 .…”

Section: Introductionmentioning

confidence: 58%

Impact of Cluster Physics on the Sunyaev-Zel'dovich Power Spectrum

Shaw

Nagai

Bhattacharya

et al. 2010

ApJ

Self Cite

223

392

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We use an analytic model to investigate the theoretical uncertainty on the thermal Sunyaev-Zel'dovich (SZ) power spectrum due to astrophysical uncertainties in the thermal structure of the intracluster medium. Our model accounts for star formation and energy feedback (from supernovae and active galactic nuclei) as well as radially dependent non-thermal pressure support due to random gas motions, the latter calibrated by recent hydrodynamical simulations. We compare the model against X-ray observations of low-redshift clusters, finding excellent agreement with observed pressure profiles. Varying the levels of feedback and non-thermal pressure support can significantly change both the amplitude and shape of the thermal SZ power spectrum. Increasing the feedback suppresses power at small angular scales, shifting the peak of the power spectrum to lower . On the other hand, increasing the nonthermal pressure support has the opposite effect, significantly reducing power at large angular scales. In general, including non-thermal pressure at the level measured in simulations has a large effect on the power spectrum, reducing the amplitude by 50% at angular scales of a few arcminutes compared to a model without a non-thermal component. Our results demonstrate that measurements of the shape of the power spectrum can reveal useful information on important physical processes in groups and clusters, especially at high redshift where there exists little observational data. Comparing with the recent South Pole Telescope measurements of the small-scale cosmic microwave background power spectrum, we find our model reduces the tension between the values of σ 8 measured from the SZ power spectrum and from cluster abundances.

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Sharpening the Precision of the Sunyaev-Zel'dovich Power Spectrum

Cited by 52 publications

References 51 publications

Optimal Capture of Non-Gaussianity in Weak-Lensing Surveys: Power Spectrum, Bispectrum, and Halo Counts

Optimal Capture of Non-Gaussianity in Weak-Lensing Surveys: Power Spectrum, Bispectrum, and Halo Counts

SEVEN-YEARWILKINSON MICROWAVE ANISOTROPY PROBE(WMAP) OBSERVATIONS: COSMOLOGICAL INTERPRETATION

Impact of Cluster Physics on the Sunyaev-Zel'dovich Power Spectrum

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