A massive, cooling-flow-induced starburst in the core of a luminous cluster of galaxies

作者：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; Dehaan 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

来源：Nature, 2012, 488(7411): 349-352.

DOI：10.1038/nature11379

In the cores of some clusters of galaxies the hot intracluster plasma is dense enough that it should cool radiatively in the cluster%26apos;s lifetime(1-3), leading to continuous %26apos;cooling flows%26apos; of gas sinking towards the cluster centre, yet no such cooling flow has been observed. The low observed star-formation rates(4,5) and cool gas masses(6) for these %26apos;cool-core%26apos; clusters suggest that much of the cooling must be offset by feedback to prevent the formation of a runaway cooling flow(7-10). 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 starformation 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.

• 出版日期2012-8-16