South Pole Telescope Detections of the Previously Unconfirmed Planck Early SZ Clusters in the Southern Hemisphere
K. Story, K. A. Aird, K. Andersson, R. Armstrong, G. Bazin, B. A. Benson, L. E. Bleem, M. Bonamente, M. Brodwin, J. E. Carlstrom, C. L. Chang, A. Clocchiatti, T… 展开作者
K. Story, K. A. Aird, K. Andersson, R. Armstrong, G. Bazin, B. A. Benson, L. E. Bleem, M. Bonamente, M. Brodwin, J. E. Carlstrom, C. L. Chang, A. Clocchiatti, T. M. Crawford, A. T. Crites, T. de Haan, S. Desai, M. A. Dobbs, J. P. Dudley, R. J. Foley, E. M. George, M. D. Gladders, A. H. Gonzalez, N. W. Halverson, F. W. High, G. P. Holder, W. L. Holzapfel, S. Hoover, J. D. Hrubes, M. Joy, R. Keisler, L. Knox, A. T. Lee, E. M. Leitch, M. Lueker, D. Luong-Van, D. P. Marrone, J. J. McMahon, J. Mehl, S. S. Meyer, J. J. Mohr, T. E. Montroy, S. Padin, T. Plagge, C. Pryke, C. L. Reichardt, A. Rest, J. Ruel, J. E. Ruhl, B. R. Saliwanchik, A. Saro, K. K. Schaffer, L. Shaw, E. Shirokoff, J. Song, H. G. Spieler, B. Stalder, Z. Staniszewski, A. A. Stark, C. W. Stubbs, K. Vanderlinde, J. D. Vieira, R. Williamson, A. Zenteno
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7 emulateapj pages, 4 figures, 1 table. Revised to match published version
We present South Pole Telescope (SPT) observations of the five galaxy cluster candidates in the southern hemisphere which were reported as unconfirmed in the Planck Early Sunyaev-Zel'dovich (ESZ) sample. One cluster candidate, PLCKESZ G255.62-46.16, is located in the 2500-square-degree SPT SZ survey region and was reported previously as SPT-CL J0411-4819. For the remaining four candidates, which are located outside of the SPT SZ survey region, we performed short, dedicated SPT observations. Each of these four candidates was strongly detected in maps made from these observations, with signal-to-noise ratios ranging from 6.3 to 13.8. We have observed these four candidates on the Magellan-Baade telescope and used these data to estimate cluster redshifts from the red sequence. Resulting redshifts range from 0.24 to 0.46. We report measurements of Y_0.75', the integrated Comptonization within a 0.75' radius, for all five candidates. We also report X-ray luminosities calculated from ROSAT All-Sky Survey catalog counts, as well as optical and improved SZ coordinates for each candidate. The combination of SPT SZ measurements, optical red-sequence measurements, and X-ray luminosity estimates demonstrates that these five Planck ESZ cluster candidates do indeed correspond to real galaxy clusters with redshifts and observable properties consistent with the rest of the ESZ sample.
The Sagittarius Streams in the Southern Galactic Hemisphere
Sloan Digital Sky Survey Data Release 8分析了南银河半球人马座流的结构。与人马座潮汐轨道平行，但距离约10度，有另一个更暗，更贫金属流。我们提供的证据表明，这两个流遵循类似的距离梯度，但有不同的形态学特性和恒星星族。较亮的星流较宽，包含更多富含金属的恒星，并且与较暗的星流相比，具有更丰富的颜色-星等图，有多个转折点和一个突出的红色团块。根据结构性质和恒星星族混合，流的配置类似于北方的“分叉”。在南银河帽区域，有来自鲸鱼座流的潮汐碎片重叠，它穿过人马座流。使用光度和光谱数据，我们表明，蓝色离散人口主要属于人马座和蓝色水平分支恒星主要属于鲸鱼座流在这个混乱的位置在晕。
