arXiv 1302.44362013-02astro-ph.CO

Herschel-ATLAS：一个双星HyLIRG精确定位一个恒星爆发原椭圆星系团

Herschel-ATLAS: a binary HyLIRG pinpointing a cluster of starbursting proto-ellipticals

R. J. Ivison, A. M. Swinbank, Ian Smail, A. I. Harris, R. S. Bussmann, A. Cooray, P. Cox, Hai Fu, A. Kovacs, M. Krips, D. Narayanan, M. Negrello, R. Neri, J. Pe… 展开作者

R. J. Ivison, A. M. Swinbank, Ian Smail, A. I. Harris, R. S. Bussmann, A. Cooray, P. Cox, Hai Fu, A. Kovacs, M. Krips, D. Narayanan, M. Negrello, R. Neri, J. Penarrubia, J. Richard, D. A. Riechers, K. Rowlands, J. G. Staguhn, T. A. Targett, S. Amber, A. J. Baker, N. Bourne, F. Bertoldi, M. Bremer, J. A. Calanog, D. L. Clements, H. Dannerbauer, A. Dariush, G. De Zotti, L. Dunne, S. A. Eales, D. Farrah, S. Fleuren, A. Franceschini, J. E. Geach, R. D. George, J. C. Helly, R. Hopwood, E. Ibar, M. J. Jarvis, J. -P. Kneib, S. Maddox, A. Omont, D. Scott, S. Serjeant, M. W. L. Smith, M. A. Thompson, E. Valiante, I. Valtchanov, J. Vieira, P. van der Werf

备注：: 15 pages, 8 colour figures; accepted for publication in ApJ
发表信息：: 2013, ApJ, 772, 137
DOI：: 10.1088/0004-637X/772/2/137

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摘要：

通过最广泛的赫歇尔河外成像巡天对最佳候选HyLIRG进行全色观测，在~100 kpc区域内发现了至少四个内在发光的z=2.41星系--一个星爆原椭圆星系团。通过亚弧秒干涉成像，我们测量了准确的气体和恒星形成的表面密度。两个最亮的星系在submm/射电连续谱和CO J=4-3时的半高宽约为3 kpc，在CO J=1-0时为2倍。宽的CO线部分是由于组成星系的数量众多，部分是由于两个反向旋转的气体盘中的大旋转速度-预测这种情况将导致最强烈的星爆，因此将成对出现。这些盘的M（dyn）为几× 10^11兆太阳能，气体含量约为40%。速度色散是适度的，所以盘是不稳定的，可能在与它们的半径相称的尺度上：这些星系正在经历恒星形成的极端爆发，而不仅仅局限于它们的核，接近爱丁顿极限。它们特定的恒星形成率使它们比主序高出5倍，而主序应该包括像这样的大型气体盘。它们的高恒星形成效率很难与简单的体积恒星形成定律相协调。N体和暗物质模拟表明，该系统是B（inary）型~10^14.6-Msun星系团的前身。

英文摘要：

Panchromatic observations of the best candidate HyLIRG from the widest Herschel extragalactic imaging survey have led to the discovery of at least four intrinsically luminous z=2.41 galaxies across a ~100-kpc region - a cluster of starbursting proto-ellipticals. Via sub-arcsecond interferometric imaging we have measured accurate gas and star-formation surface densities. The two brightest galaxies span ~3 kpc FWHM in submm/radio continuum and CO J=4-3, and double that in CO J=1-0. The broad CO line is due partly to the multitude of constituent galaxies and partly to large rotational velocities in two counter-rotating gas disks -- a scenario predicted to lead to the most intense starbursts, which will therefore come in pairs. The disks have M(dyn) of several x 10^11 Msun, and gas fractions of ~40%. Velocity dispersions are modest so the disks are unstable, potentially on scales commensurate with their radii: these galaxies are undergoing extreme bursts of star formation, not confined to their nuclei, at close to the Eddington limit. Their specific star-formation rates place them ~>5x above the main sequence, which supposedly comprises large gas disks like these. Their high star-formation efficiencies are difficult to reconcile with a simple volumetric star-formation law. N-body and dark matter simulations suggest this system is the progenitor of a B(inary)-type ~10^14.6-Msun cluster.

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