Cross Correlation of the Cosmic Microwave Background with Radio Sources: Constraints on an Accelerating Universe

Boughn, Stephen P.; Crittenden, Robert

doi:10.1103/physrevlett.88.021302

Cited by 64 publications

(105 citation statements)

References 25 publications

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“…(iv) Radio sources: The NRAO VLA Sky Survey [39] sample has been used to probe the moderate redshift range z ∼ 1, but its redshift distribution is still under debate [40,41,36]. More importantly the maps exhibit declination-dependent striping which is almost certainly a systematic artifact and precludes determination of the dipole [42]. (v) Lyman-α forest: A different approach would be to measure a fluctuation amplitude from the Lyman-α forest at the same redshift but with sightlines in different parts of the sky.…”

Section: Choice Of Datasetmentioning

confidence: 99%

Constraints on cosmic hemispherical power anomalies from quasars

Hirata¹

2009

J. Cosmol. Astropart. Phys.

109

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Abstract. Recent analyses of the cosmic microwave background (CMB) maps from the WMAP satellite have uncovered evidence for a hemispherical power anomaly, i.e. a dipole modulation of the CMB power spectrum at large angular scales with an amplitude of ±14 percent. Erickcek et al have put forward an inflationary model to explain this anomaly. Their scenario is a variation on the curvaton scenario in which the curvaton possesses a large-scale spatial gradient that modulates the amplitude of CMB fluctuations. We show that this scenario would also lead to a spatial gradient in the amplitude of perturbations σ 8 , and hence to a dipole asymmetry in any highly biased tracer of the underlying density field. Using the high-redshift quasars from the Sloan Digital Sky Survey, we find an upper limit on such a gradient of |∇σ 8 |/σ 8 < 0.027r −1 lss (99% posterior probability), where r lss is the comoving distance to the last-scattering surface. This rules out the simplest version of the curvaton spatial gradient scenario.

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Section: Choice Of Datasetmentioning

confidence: 99%

Constraints on cosmic hemispherical power anomalies from quasars

Hirata¹

2009

J. Cosmol. Astropart. Phys.

109

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“…Finally, it is possible that microwave emission from the radio/X-ray sources themselves could result in the positive correlation of the maps. However, extrapolations of the frequency spectra of the radio galaxies indicate that the microwave emission is much smaller than the observed signal [6]. In addition, the clustering of radio sources is on a much smaller angular scale than the apparent signals, and any such contamination would appear only at θ = 0 • and not at larger angles [15].…”

mentioning

confidence: 97%

“…In order to predict the expected level of the ISW effect in these two surveys, it is essential to know both the inherent clustering of the sources and their distribution in redshift. The former can be determined from previous studies of the X-ray and radio auto-correlation functions [6,7] while the latter can be estimated from deep, pointed surveys [8,9]. The detailed considerations for calculating the amplitude of the ISW effect can be found elsewhere [3,10].…”

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confidence: 99%

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A correlation between the cosmic microwave background and large-scale structure in the Universe

Boughn

Crittenden²

2004

Nature

338

357

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The fluctuations in the cosmic microwave background (CMB) have proved an invaluable tool for uncovering the nature of our universe. The recent dramatic data provided by the WMAP satellite [1] have confirmed previous indications that the expansion of the universe may be accelerating [2], driven by a cosmological constant or similar dark energy component. One consequence of dark energy is the suppression of the rate of gravitational collapse of matter at relatively recent times. This causes fluctuations in the CMB to be created as the photons pass through nearby large scale structures, a phenomenon known as the integrated Sachs-Wolfe (ISW) effect. The result is additional large scale fluctuations in the CMB which are correlated with the relatively nearby (i.e., at redshift z ∼ 1) matter distribution [3]. Here we report evidence of correlations between the WMAP data and two all sky probes of large scale structure, the hard X-ray background observed by the HEAO-1 satellite [4] and the NVSS survey of radio galaxies [5]. Both observed correlations are consistent with an ISW origin, indicating that we are seeing the impact of dark energy on the growth of structure.In the standard model of the origin of structure, most of the fluctuations were imprinted on the CMB at the epoch of last scattering, when the universe was 400,000 years old (z ≃ 1100.) The ISW effect induces extra fluctuations only when matter domination ends and the dark energy becomes important dynamically (z ∼ 1.) When this happens, the gravitational potentials of large, diffuse concentrations and rarefactions of matter begin to decay and the energy of photons passing through them changes by an amount that depends on the depth of the potentials. The amplitude of these ISW fluctuations tends to be small compared to the fluctuations originating at the epoch of last scattering except on very large scales. However, since ISW fluctuations were created more recently, it is expected that the CMB fluctuations should be partially correlated with tracers of the large scale matter distribution, e.g., with the distribution of distant galaxies.Detecting the relatively weak correlation of the CMB with the distribution of galaxies requires nearly full sky surveys out to redshifts z ∼ 1. Focus has thus has been on luminous active galaxies, which are believed to trace the mass distribution on large scales. While active galaxies emit at a wide range of frequencies, the most useful maps are in the hard X-rays (2-10 KeV), where they dominate the X-ray sky, and 1

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“…The cross-correlation function (CCF) is a suitable tool for studying the ISW effect via cross-correlation of the CMB fluctuations and tracers of the LSS, and it has been one of the most extensively used in this context (e.g., Boughn & Crittenden 2002;Giannantonio et al 2008;Xia et al 2009). On the one hand, the signal only appears at very large scales and, therefore, it is sufficient to work at resolutions at which the low performance of the CCF (in terms of computational time) is not a serious handicap.…”

Section: Cross-correlation Functionmentioning

confidence: 99%

Planck2013 results. XIX. The integrated Sachs-Wolfe effect

Ade¹,

Aghanim²,

Armitage-Caplan³

et al. 2014

A&A

134

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Based on cosmic microwave background (CMB) maps from the 2013 Planck Mission data release, this paper presents the detection of the integrated Sachs-Wolfe (ISW) effect, that is, the correlation between the CMB and large-scale evolving gravitational potentials. The significance of detection ranges from 2 to 4σ, depending on which method is used. We investigated three separate approaches, which essentially cover all previous studies, and also break new ground. (i) We correlated the CMB with the Planck reconstructed gravitational lensing potential (for the first time). This detection was made using the lensing-induced bispectrum between the low-and high-temperature anisotropies; the correlation between lensing and the ISW effect has a significance close to 2.5σ. (ii) We cross-correlated with tracers of large-scale structure, which yielded a significance of about 3σ, based on a combination of radio (NVSS) and optical (SDSS) data. (iii) We used aperture photometry on stacked CMB fields at the locations of known large-scale structures, which yielded and confirms a 4σ signal, over a broader spectral range, when using a previously explored catalogue, but shows strong discrepancies in amplitude and scale when compared with expectations. More recent catalogues give more moderate results that range from negligible to 2.5σ at most, but have a more consistent scale and amplitude, the latter being still slightly higher than what is expected from numerical simulations within ΛCMD. Where they can be compared, these measurements are compatible with previous work using data from WMAP, where these scales have been mapped to the limits of cosmic variance. Planck's broader frequency coverage allows for better foreground cleaning and confirms that the signal is achromatic, which makes it preferable for ISW detection. As a final step we used tracers of large-scale structure to filter the CMB data, from which we present maps of the ISW temperature perturbation. These results provide complementary and independent evidence for the existence of a dark energy component that governs the currently accelerated expansion of the Universe.

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Cross Correlation of the Cosmic Microwave Background with Radio Sources: Constraints on an Accelerating Universe

Cited by 64 publications

References 25 publications

Constraints on cosmic hemispherical power anomalies from quasars

Constraints on cosmic hemispherical power anomalies from quasars

A correlation between the cosmic microwave background and large-scale structure in the Universe

Planck2013 results. XIX. The integrated Sachs-Wolfe effect

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