Publications (4)5.53 Total impact
[show abstract] [hide abstract]
ABSTRACT: We present gas constraints from Sunyaev-Zel'dovich (SZ) effect measurements in a sample of 11 X-ray and infrared (IR) selected galaxy clusters at z≥1, using data from the Sunyaev-Zel'dovich Array (SZA). The cylindrically integrated Compton-y parameter, Y, is calculated by fitting the data to a two-parameter gas pressure profile. Where possible, we also determine the temperature of the hot intracluster plasma from Chandra and XMM-Newton data and constrain the gas mass within the same aperture (r 2500) as Y. The SZ effect is detected in the clusters for which the X-ray data indicate gas masses above ~1013 M ☉, including XMMU J2235 – 2557 at redshift z = 1.39, which to date is one of the most distant clusters detected using the SZ effect. None of the IR-selected targets are detected by the SZA measurements, indicating low gas masses for these objects. For these and the four other undetected clusters, we quote upper limits on Y and M gas,SZ, with the latter derived from scaling relations calibrated with lower redshift clusters. We compare the constraints on Y and X-ray-derived gas mass M gas,X-ray to self-similar scaling relations between these observables determined from observations of lower redshift clusters, finding consistency given the measurement error.The Astrophysical Journal Letters 10/2010; 723(1):L78. · 5.53 Impact Factor
Article: Application of a Self-Similar Pressure Profile to Sunyaev-Zel'dovich Effect Data from Galaxy Clusters[show abstract] [hide abstract]
ABSTRACT: We investigate the utility of a new, self-similar pressure profile for fitting Sunyaev-Zel'dovich (SZ) effect observations of galaxy clusters. Current SZ imaging instruments - such as the Sunyaev-Zel'dovich Array (SZA) - are capable of probing clusters over a large range in physical scale. A model is therefore required that can accurately describe a cluster's pressure profile over a broad range of radii, from the core of the cluster out to a significant fraction of the virial radius. In the analysis presented here, we fit a radial pressure profile derived from simulations and detailed X-ray analysis of relaxed clusters to SZA observations of three clusters with exceptionally high quality X-ray data: A1835, A1914, and CL J1226.9+3332. From the joint analysis of the SZ and X-ray data, we derive physical properties such as gas mass, total mass, gas fraction and the intrinsic, integrated Compton y-parameter. We find that parameters derived from the joint fit to the SZ and X-ray data agree well with a detailed, independent X-ray-only analysis of the same clusters. In particular, we find that, when combined with X-ray imaging data, this new pressure profile yields an independent electron radial temperature profile that is in good agreement with spectroscopic X-ray measurements.09/2008;
Article: The Sunyaev-Zel'dovich Array[show abstract] [hide abstract]
ABSTRACT: We present a description and update of the Sunyaev-Zel'dovich Array (SZA), an interferometer designed specifically for the detection of galaxy clusters using the Sunyaev-Zel'dovich Effect. The array consists of eight 3.5 meter telescopes outfitted with 26-36 GHz and 85-115 GHz receivers and a digital correlator covering 8 GHz. The compact baselines and broad correlation bandwith are designed to provide high sensitivity to the SZ effect from galaxy clusters. The array is now fully operational at 30 GHz and is starting a twelve-degree blind survey. The 90 GHz system will be used to conduct high resolution targeted observations and of individual clusters and to confirm the clusters found in the 30 GHz survey.11/2005; 37:1225.