Herschel-ATLAS: a binary HyLIRG pinpointing a cluster of starbursting proto-ellipticals
| Autor: | Ivison, R. J., Swinbank, A. M., Smail, Ian, Harris, A. I., Bussmann, R. S., Cooray, A., Cox, P., Fu, Hai, Kovacs, A., Krips, M., Narayanan, D., Negrello, M., Neri, R., Penarrubia, J., Richard, J., Riechers, D. A., Rowlands, K., Staguhn, J. G., Targett, T. A., Amber, S., Baker, A. J., Bourne, N., Bertoldi, F., Bremer, M., Calanog, J. A., Clements, D. L., Dannerbauer, H., Dariush, A., De Zotti, G., Dunne, L., Eales, S. A., Farrah, D., Fleuren, S., Franceschini, A., Geach, J. E., George, R. D., Helly, J. C., Hopwood, R., Ibar, E., Jarvis, M. J., Kneib, J. -P., Maddox, S., Omont, A., Scott, D., Serjeant, S., Smith, M. W. L., Thompson, M. A., Valiante, E., Valtchanov, I., Vieira, J., van der Werf, P. |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | 2013, ApJ, 772, 137 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1088/0004-637X/772/2/137 |
| Popis: | 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. Comment: 15 pages, 8 colour figures; accepted for publication in ApJ |
| Databáze: | arXiv |
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