Peculiar Velocity Limits from Measurements of the Spectrum of the Sunyaev‐Zeldovich Effect in Six Clusters of Galaxies

Abstract

We have made measurements of the Sunyaev-Zel'dovich (SZ) effect in six galaxy clusters at z > 0.2 using the Sunyaev-Zel'dovich Infrared Experiment (SuZIE II) in three frequency bands between 150 and 350 GHz. Simultaneous multi-frequency measurements have been used to distinguish between thermal and kinematic components of the SZ effect, and to significantly reduce the effects of variations in atmospheric emission which can otherwise dominate the noise. We have set limits to the peculiar velocities of each cluster with respect to the Hubble flow, and have used the cluster sample to set a 95% confidence limit of < 1410 km s −1 to the bulk flow of the intermediate-redshift universe in the direction of the CMB dipole. This is the first time that SZ measurements have been used to constrain bulk flows. We show that systematic uncertainties in peculiar velocity determinations from the SZ effect are likely to be dominated by submillimeter point sources and we discuss the level of this contamination.

Dark energy constraints from galaxy cluster peculiar velocities

“…The kinematic Sunyaev-Zeldovich effect in clusters of galaxies promises a direct tracer of this signal, with errors largely independent of cluster redshift. Although the current uncertainty in velocity measurements is large with σ v ≈ 1000 km/s [55] for individual clusters, upcoming multi-band experiments like ACT [56] or SPT [28] with arcminute resolution and few µK sensitivity have the potential to measure peculiar velocities with velocity errors of a few hundred km/s for large samples of clusters, opening a new window on the evolution of the universe. We have considered three separate cluster velocity statistics here, computing them using the halo model and comparing with numerical results.…”

Constraints on Gravity and Dark Energy From the Pairwise Kinematic Sunyaev–zel’dovich Effect

“…Despite its potential, the kSZ has been hard to measure; the signal is small when compared to the thermal SZ effect and emission from dusty galaxies, and does not have a distinct frequency dependence. Observational efforts to constrain the cluster peculiar velocities have come from multi-band photometry in combination with X-ray spectra (Holzapfel et al 1997;Benson et al 2003;Kitayama et al 2004;Mauskopf et al 2012;Mroczkowski et al 2012) and spectroscopy around the thermal SZ null frequency (Zemcov et al 2012). Recent work extracted the kSZ signature from individual clusters by combining sub-millimeter, X-ray and sub-arcminute resolution CMB data to respectively remove dusty galaxy emission, estimate electron density and fit thermal and kSZ templates (Sayers et al 2013).…”

Peculiar Velocity Constraints From Five-Band Sz Effect Measurements Toward Rx J1347.5−1145 With Music and Bolocam From the Cso

“…Furthermore, data from Planck, ACT, and the ground-based South Pole Telescope imply a non-zero kinetic SZ effect power spectrum on small angular scales (Sievers et al 2013;George et al 2015;Planck Collaboration et al 2015b). Complementary to these large statistical analyses, several efforts have also been made to detect the kinetic SZ effect signal in individual clusters using multi-band ground-based measurements (Benson et al 2003;Kitayama et al 2004;Mauskopf et al 2012;Mroczkowski et al 2012;Zemcov et al 2012;Adam et al 2015;Lindner et al 2015), with an exceptionally high velocity merging component in the cluster MACS J0717.5+3745 producing the highest significance detection to date (Sayers et al 2013c). …”

“…For example, if we eliminate these noise sources from our analysis, then the uncertainties on e t and v pec are reduced by approximately a factor of two to 0.44 10 3 ´-and ±460 km s −1 , respectively. In addition, more advanced data-processing algorithms to remove the atmospheric fluctuations that are correlated between the four MUSIC observing bands may produce noticeable improvements (Benson et al 2003;Adam et al 2014). Note.…”