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GALAXY CLUSTERS DISCOVERED VIA THE SUNYAEV-ZEL'DOVICH EFFECT IN THE 2500-SQUARE-DEGREE SPT-SZ SURVEY
Bleem, L. E.,Stalder, B.,de Haan, T.,Aird, K. A.,Allen, S. W.,Applegate, D. E.,Ashby, M. L. N.,Bautz, M.,Bayliss, M.,Benson, B. A.,Bocquet, S.,Brodwin, M.,Carlstrom, J. E.,Chang, C. L.,Chiu, I.,Cho, H IOP Publishing 2015 The Astrophysical journal Supplement series Vol.216 No.2
<P>We present a catalog of galaxy clusters selected via their Sunyaev-Zel'dovich (SZ) effect signature from 2500 deg(2) of South Pole Telescope (SPT) data. This work represents the complete sample of clusters detected at high significance in the 2500 deg(2) SPT-SZ survey, which was completed in 2011. A total of 677 (409) cluster candidates are identified above a signal-to-noise threshold of xi = 4.5 (5.0). Ground-and space-based optical and near-infrared (NIR) imaging confirms overdensities of similarly colored galaxies in the direction of 516 (or 76%) of the xi > 4.5 candidates and 387 (or 95%) of the xi > 5 candidates; the measured purity is consistent with expectations from simulations. Of these confirmed clusters, 415 were first identified in SPT data, including 251 new discoveries reported in this work. We estimate photometric redshifts for all candidates with identified optical and/or NIR counterparts; we additionally report redshifts derived from spectroscopic observations for 141 of these systems. The mass threshold of the catalog is roughly independent of redshift above z similar to 0.25 leading to a sample of massive clusters that extends to high redshift. The median mass of the sample is M-500c(rho(crit)) similar to 3.5 x 10(14) M-circle dot h(70)(-1) 70, the median redshift is z(med) = 0.55, and the highest-redshift systems are at z > 1.4. The combination of large redshift extent, clean selection, and high typical mass makes this cluster sample of particular interest for cosmological analyses and studies of cluster formation and evolution.</P>
Baryon content of massive galaxy clusters at 0.57 < <i>z</i> < 1.33
Chiu, I.,Mohr, J.,McDonald, M.,Bocquet, S.,Ashby, M. L. N.,Bayliss, M.,Benson, B. A.,Bleem, L. E.,Brodwin, M.,Desai, S.,Dietrich, J. P.,Forman, W. R.,Gangkofner, C.,Gonzalez, A. H.,Hennig, C.,Liu, J. Oxford University Press 2016 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.455 No.1
Hlavacek-Larrondo, J.,McDonald, M.,Benson, B. A.,Forman, W. R.,Allen, S. W.,Bleem, L. E.,Ashby, M. L. N.,Bocquet, S.,Brodwin, M.,Dietrich, J. P.,Jones, C.,Liu, J.,Reichardt, C. L.,Saliwanchik, B. R.,S IOP Publishing 2015 The Astrophysical journal Vol.805 No.1
<P>X-ray cavities are key tracers of mechanical (or radio mode) heating arising from the active galactic nuclei (AGNs) in brightest cluster galaxies (BCGs). We report on a survey for X-ray cavities in 83 massive, high-redshift (0.4 < z < 1.2) clusters of galaxies selected by their Sunyaev-Zel'dovich signature in the South Pole Telescope data. Based on Chandra X-ray images, we find a total of six clusters having symmetric pairs of surface brightness depressions consistent with the picture of radio jets inflating X-ray cavities in the intracluster medium (ICM). The majority of these detections are of relatively low significance and require deeper follow-up data in order to be confirmed. Further, this search will miss small (<10 kpc) X-ray cavities that are unresolved by Chandra at high (z greater than or similar to 5) redshift. Despite these limitations, our results suggest that the power generated by AGN feedback in BCGs has remained unchanged for over half of the age of the universe (>7 Gyr at z similar to 0.8). On average, the detected X-ray cavities have powers of (0.8-5) x 10(45) erg s(-1), enthalpies of (3-6) x 10(59) erg, and radii of similar to 17 kpc. Integrating over 7 Gyr, we find that the supermassive black holes in BCGs may have accreted 10(8) to several 10(9) M-circle dot of material to power these outflows. This level of accretion indicates that significant supermassive black hole growth may occur not only at early times, in the quasar era, but at late times as well. We also find that X-ray cavities at high redshift may inject an excess heat of 0.1-1.0 keV per particle into the hot ICM above and beyond the energy needed to offset cooling. Although this result needs to be confirmed, we note that the magnitude of excess heating is similar to the energy needed to preheat clusters, break self-similarity, and explain the excess entropy in hot atmospheres.</P>