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Durham University

Department of Physics

Staff profile

Publication details for Professor Ian Smail

Oteo, I., Ivison, R.J., Dunne, L., Smail, I., Swinbank, A.M., Zhang, Z.-Y., Lewis, A., Maddox, S., Riechers, D., Serjeant, S., Van der Werf, P., Biggs, A.D., Bremer, M., Cigan, P., Clements, D.L., Cooray, A., Dannerbauer, H., Eales, S., Ibar, E., Messias, H., Michałowski, M.J., Pérez-Fournon, I. & van Kampen, E. (2016). Witnessing the Birth of the Red Sequence: ALMA High-resolution Imaging of [C II] and Dust in Two Interacting Ultra-red Starbursts at z = 4.425. The Astrophysical Journal 827(1): 34.

Author(s) from Durham

Abstract

Exploiting the sensitivity and spatial resolution of the Atacama Large Millimeter/submillimeter Array, we have studied the morphology and the physical scale of the interstellar medium—both gas and dust—in SGP 38326, an unlensed pair of interacting starbursts at z = 4.425. SGP 38326 is the most luminous star bursting system known at z > 4, with a total IR luminosity of L IR ~ 2.5 × 1013 L ⊙ and a star formation rate of ~ 4500 M ⊙ yr−1. SGP 38326 also contains a molecular gas reservoir among the most massive yet found in the early universe, and it is the likely progenitor of a massive, red-and-dead elliptical galaxy at z ~ 3. Probing scales of ~0farcs1 or ~800 pc we find that the smooth distribution of the continuum emission from cool dust grains contrasts with the more irregular morphology of the gas, as traced by the [C ii] fine structure emission. The gas is also extended over larger physical scales than the dust. The velocity information provided by the resolved [C ii] emission reveals that the dynamics of the two interacting components of SGP 38326 are each compatible with disk-like, ordered rotation, but also reveals an ISM which is turbulent and unstable. Our observations support a scenario where at least a subset of the most distant extreme starbursts are highly dissipative mergers of gas-rich galaxies.