Mass selection bias in galaxy cluster peculiar velocities from the kinetic Sunyaev-Zel'dovich effect

Peel, Alan

doi:10.1111/j.1365-2966.2005.09804.x

Cited by 14 publications

(18 citation statements)

References 30 publications

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“…Although the above expression holds for both the parallel and perpendicular components, in simulations Ψ is mostly negative or zero due to the heavy influence of infall at large separations [44]. However, this anticorrelation is not seen in linear perturbation theory or in the halo model, which both predict positive correlation for pair comoving separations less than 40 Mpc; for separations larger than 40 Mpc, the theory and simulations are consistent, but the parallel component correlation is essentially zero.…”

Section: Velocity Correlation Functionmentioning

confidence: 78%

“…Assuming statistical isotropy, the only non-trivial correlations will be of the velocity components along the line connecting the clusters and of the velocity components perpendicular to the line connecting the clusters; furthermore, these correlations will only depend on the separation r = |r i − r j |. Geometrically, the correlation of radial velocities must be of the form [44] …”

Section: Velocity Correlation Functionmentioning

confidence: 99%

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Dark energy constraints from galaxy cluster peculiar velocities

2008

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Future multifrequency microwave background experiments with arcminute resolution and microKelvin temperature sensitivity will be able to detect the kinetic Sunyaev-Zeldovich effect, providing a way to measure radial peculiar velocities of massive galaxy clusters. We show that cluster peculiar velocities have the potential to constrain several dark energy parameters. We compare three velocity statistics (the distribution of radial velocities, the mean pairwise streaming velocity, and the velocity correlation function) and analyze the relative merits of these statistics in constraining dark energy parameters. Of the three statistics, mean pairwise streaming velocity provides constraints that are least sensitive to velocity errors: the constraints on parameters degrades only by a factor of two when the random error is increased from 100 to 500 km/s. We also compare cluster velocities with other dark energy probes proposed in the Dark Energy Task Force report. For cluster velocity measurements with realistic priors, the eventual constraints on the dark energy density, the dark energy equation of state and its evolution are comparable to constraints from supernovae measurements, and better than cluster counts and baryon acoustic oscillations; adding velocity to other dark energy probes improves constraints on the figure of merit by more than a factor of two. For upcoming Sunyaev-Zeldovich galaxy cluster surveys, even velocity measurements with errors as large as 1000 km/s will substantially improve the cosmological constraints compared to using the cluster number density alone.PACS numbers: 95.36.+x, 98.65.Cw,

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Section: Velocity Correlation Functionmentioning

confidence: 78%

Section: Velocity Correlation Functionmentioning

confidence: 99%

Dark energy constraints from galaxy cluster peculiar velocities

2008

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“…conducted a thorough study of peculiar velocities in simulations, in which they showed that halo peculiar velocities depend also upon the environment density, but even in the extreme cases the change in peculiar velocity would be smaller than ∼70% of the average value. Peel (2006) found an average bias of ∼30% of the halo peculiar velocity when compared to linear theory predictions.…”

Section: Impact On Ksz Estimationsmentioning

confidence: 97%

Galaxy clusters as mirrors of the distant Universe

Hernández-Monteagudo¹,

Sunyaev²

2010

A&A

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It is well known that Thomson scattering of cosmic microwave background (CMB) photons in galaxy clusters introduces new anisotropies in the CMB radiation field, but still little attention is payed to the fraction of CMB photons that are scattered off the line of sight, causing a slight blurring of the CMB anisotropies present at the moment of scattering. In this work we study this blurring effect and find that it can provide an independent measurement of the cluster's gas mass. Likewise, this effect has a non-negligible impact on estimations of the kSZ effect: it induces a 10% correction in 20−40% of the clusters/groups and a dominant over kSZ correction in ∼5% of the clusters in an ideal (noiseless) experiment. For rich clusters, CMB, tSZ and X-ray observations can provide estimates for the amplitude and sign of the blurring effect that can be used for correcting kSZ estimations. We explore the possibility of using this blurring term to probe the CMB anisotropy field at different epochs in our Universe. In particular, we study the required precision in the removal of the kSZ which enables us to detect the blurring term −τ T δT/T 0 in galaxy cluster populations placed at different redshift shells. By mapping this term in those shells, we provide a tomographic probe for the growth of the Integrated Sachs-Wolfe effect (ISW) during the late evolutionary stages of the Universe. We find that the required precision on the removal of the cluster's peculiar velocity is of the order of 100−200 km s −1 in the redshift range 0.2−0.8, after assuming that all clusters more massive than 10 14 h −1 M are observable. These errors are comparable to the total expected linear line of sight velocity dispersion for clusters in WMAPV cosmogony and correspond to a residual level of roughly 900−1800 τ T μK per cluster, including all types of contaminants and systematics. Were this precision requirement achieved, then independent constraints on the intrinsic cosmological dipole would be simultaneously provided.

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“…For this reason, this frequency becomes an ideal window for searching for the kSZ in galaxy clusters. The kSZ effect generated in the galaxy cluster population has been studied extensively (Peel 2006;Bhattacharya & Kosowsky 2007. In particular, in an analysis of the correlation properties of the cluster peculiar motion was provided.…”

Section: The Clusters As Probes Of Bulk Flowsmentioning

confidence: 99%

“…The halo mass function dn/dM is approximated by that of Sheth & Tormen (1999). Motivated by Peel (2006), the velocity bias was approximated by b v = 1.3 for all halos (although the particular choice of this parameter has very little impact on our results, as we shall see below). We set M max = 10 16 M ⊙ , and compared our results for different choices of the minimum mass M min .…”

Section: The Clusters As Probes Of Bulk Flowsmentioning

confidence: 99%

Missing baryons, bulk flows, and the E-mode polarization of the Cosmic Microwave Background

Hernández-Monteagudo¹,

Sunyaev²

2008

A&A

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Context. Most of the missing baryons are found in slightly overdense structures like filaments and superclusters, but to date most of them have remained hidden to observations. Similarly, the linear cosmological perturbation theory predicts the existence of extended bulk flows seeded by gravitational attraction of linear potential wells, but again these remain undetected. Aims. Unveil the signature of bulk flows of the missing baryons in upcoming Cosmic Microwave Background (CMB) data. Methods. If the peculiar motion of galaxy groups and clusters indeed resembles that of the surrounding baryons, then the kinetic Sunyaev-Zel'dovich (kSZ) pattern of those massive halos should be closely correlated to the kSZ pattern of all surrounding electrons. Likewise, it should also be correlated to the CMB E-mode polarization field generated via Thomson scattering after reionization. We explore the cross-correlation of the kSZ generated in groups and clusters to the all sky E-mode polarization in the context of upcoming CMB experiments like Planck, ACT, SPT or APEX. Results. We find that this cross-correlation is effectively probing redshifts below z = 3 − 4 (where most of baryons are missing), and that it arises in the very large scales (l < 10). The significance with which this cross-correlation can be measured depends on the Poissonian uncertainty associated to the number of halos where the kSZ is measured and on the accuracy of the kSZ estimations themselves. Assuming that Planck can provide a cosmic variance limited E-mode polarization map at l < 20 and S/N ∼ 1 kSZ estimates can be gathered for all clusters more massive than 10 14 M ⊙ , then this cross-correlation should be measured at the 2-3 σ level. Further, if an all-sky ACT or SPT type CMB experiment provides kSZ measurements for all halos above 10 13 M ⊙ , then the cross-correlation signal to noise (S/N) ratio should be at the level of 4-5. A detection of this cross-correlation would provide direct and definite evidence of bulk flows and missing baryons simultaneously.

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Mass selection bias in galaxy cluster peculiar velocities from the kinetic Sunyaev-Zel'dovich effect

Cited by 14 publications

References 30 publications

Dark energy constraints from galaxy cluster peculiar velocities

Dark energy constraints from galaxy cluster peculiar velocities

Galaxy clusters as mirrors of the distant Universe

Missing baryons, bulk flows, and the E-mode polarization of the Cosmic Microwave Background

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