ALBERT

Description: In the cores of some clusters of galaxies the hot intracluster plasma is dense enough that it should cool radiatively in the cluster's lifetime, leading to continuous 'cooling flows' of gas sinking towards the cluster centre, yet no such cooling flow has been observed. The low observed star-formation rates and cool gas masses for these 'cool-core' clusters suggest that much of the cooling must be offset by feedback to prevent the formation of a runaway cooling flow. Here we report X-ray, optical and infrared observations of the galaxy cluster SPT-CLJ2344-4243 (ref. 11) at redshift z = 0.596. These observations reveal an exceptionally luminous (8.2 x 10(45) erg s(-1)) galaxy cluster that hosts an extremely strong cooling flow (around 3,820 solar masses a year). Further, the central galaxy in this cluster appears to be experiencing a massive starburst (formation of around 740 solar masses a year), which suggests that the feedback source responsible for preventing runaway cooling in nearby cool-core clusters may not yet be fully established in SPT-CLJ2344-4243. This large star-formation rate implies that a significant fraction of the stars in the central galaxy of this cluster may form through accretion of the intracluster medium, rather than (as is currently thought) assembling entirely via mergers.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉McDonald, M -- Bayliss, M -- Benson, B A -- Foley, R J -- Ruel, J -- Sullivan, P -- Veilleux, S -- Aird, K A -- Ashby, M L N -- Bautz, M -- Bazin, G -- Bleem, L E -- Brodwin, M -- Carlstrom, J E -- Chang, C L -- Cho, H M -- Clocchiatti, A -- Crawford, T M -- Crites, A T -- de Haan, T -- Desai, S -- Dobbs, M A -- Dudley, J P -- Egami, E -- Forman, W R -- Garmire, G P -- George, E M -- Gladders, M D -- Gonzalez, A H -- Halverson, N W -- Harrington, N L -- High, F W -- Holder, G P -- Holzapfel, W L -- Hoover, S -- Hrubes, J D -- Jones, C -- Joy, M -- Keisler, R -- Knox, L -- Lee, A T -- Leitch, E M -- Liu, J -- Lueker, M -- Luong-Van, D -- Mantz, A -- Marrone, D P -- McMahon, J J -- Mehl, J -- Meyer, S S -- Miller, E D -- Mocanu, L -- Mohr, J J -- Montroy, T E -- Murray, S S -- Natoli, T -- Padin, S -- Plagge, T -- Pryke, C -- Rawle, T D -- Reichardt, C L -- Rest, A -- Rex, M -- Ruhl, J E -- Saliwanchik, B R -- Saro, A -- Sayre, J T -- Schaffer, K K -- Shaw, L -- Shirokoff, E -- Simcoe, R -- Song, J -- Spieler, H G -- Stalder, B -- Staniszewski, Z -- Stark, A A -- Story, K -- Stubbs, C W -- Suhada, R -- van Engelen, A -- Vanderlinde, K -- Vieira, J D -- Vikhlinin, A -- Williamson, R -- Zahn, O -- Zenteno, A -- England -- Nature. 2012 Aug 16;488(7411):349-52. doi: 10.1038/nature11379.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA. mcdonald@space.mit.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/22895340" target="_blank"〉PubMed〈/a〉

Description: In the past decade, our understanding of galaxy evolution has been revolutionized by the discovery that luminous, dusty starburst galaxies were 1,000 times more abundant in the early Universe than at present. It has, however, been difficult to measure the complete redshift distribution of these objects, especially at the highest redshifts (z 〉 4). Here we report a redshift survey at a wavelength of three millimetres, targeting carbon monoxide line emission from the star-forming molecular gas in the direction of extraordinarily bright millimetre-wave-selected sources. High-resolution imaging demonstrates that these sources are strongly gravitationally lensed by foreground galaxies. We detect spectral lines in 23 out of 26 sources and multiple lines in 12 of those 23 sources, from which we obtain robust, unambiguous redshifts. At least 10 of the sources are found to lie at z 〉 4, indicating that the fraction of dusty starburst galaxies at high redshifts is greater than previously thought. Models of lens geometries in the sample indicate that the background objects are ultra-luminous infrared galaxies, powered by extreme bursts of star formation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Vieira, J D -- Marrone, D P -- Chapman, S C -- De Breuck, C -- Hezaveh, Y D -- Weibeta, A -- Aguirre, J E -- Aird, K A -- Aravena, M -- Ashby, M L N -- Bayliss, M -- Benson, B A -- Biggs, A D -- Bleem, L E -- Bock, J J -- Bothwell, M -- Bradford, C M -- Brodwin, M -- Carlstrom, J E -- Chang, C L -- Crawford, T M -- Crites, A T -- de Haan, T -- Dobbs, M A -- Fomalont, E B -- Fassnacht, C D -- George, E M -- Gladders, M D -- Gonzalez, A H -- Greve, T R -- Gullberg, B -- Halverson, N W -- High, F W -- Holder, G P -- Holzapfel, W L -- Hoover, S -- Hrubes, J D -- Hunter, T R -- Keisler, R -- Lee, A T -- Leitch, E M -- Lueker, M -- Luong-Van, D -- Malkan, M -- McIntyre, V -- McMahon, J J -- Mehl, J -- Menten, K M -- Meyer, S S -- Mocanu, L M -- Murphy, E J -- Natoli, T -- Padin, S -- Plagge, T -- Reichardt, C L -- Rest, A -- Ruel, J -- Ruhl, J E -- Sharon, K -- Schaffer, K K -- Shaw, L -- Shirokoff, E -- Spilker, J S -- Stalder, B -- Staniszewski, Z -- Stark, A A -- Story, K -- Vanderlinde, K -- Welikala, N -- Williamson, R -- England -- Nature. 2013 Mar 21;495(7441):344-7. doi: 10.1038/nature12001. Epub 2013 Mar 13.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, USA. vieira@caltech.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23485967" target="_blank"〉PubMed〈/a〉