Dye, S., Furlanetto, C., Swinbank, A.M., Vlahakis, C., Nightingale, J.W., Dunne, L., Eales, S.A., Smail, Ian, Oteo, I., Hunter, T., Negrello, M., Dannerbauer, H., Ivison, R.J., Gavazzi, R., Cooray, A. and van der Werf, Paul
(2015)
Revealing the complex nature of the strong gravitationally lensed system H-ATLAS J090311.6+003906 using ALMA.
Monthly Notices of the Royal Astronomical Society, 452
(3).
pp. 2258-2268.
ISSN 1365-2966
Abstract
We have modelled Atacama Large Millimetre/sub-millimetre Array (ALMA) long baseline imaging of the strong gravitational lens system H-ATLAS J090311.6+003906 (SDP.81). We have reconstructed the distribution of band 6 and 7 continuum emission in the z = 3.042 source and determined its kinematic properties by reconstructing CO(5 4) and CO(8–7) line emission in bands 4 and 6. The continuum imaging reveals a highly non-uniform distribution of dust with clumps on scales of ∼200 pc. In contrast, the CO line emission shows a relatively smooth, disc-like velocity field which is well fitted by a rotating disc model with an inclination angle of (40 ± 5)◦ and an asymptotic rotation velocity of 320 km s−1. The inferred dynamical mass within 1.5 kpc is (3.5 ± 0.5) × 1010 MΘ which is comparable to the total molecular gas masses of (2.7 ± 0.5) × 1010 MΘ and (3.5 ± 0.6) × 1010 MΘ from the dust continuum emission and CO emission, respectively. Our new reconstruction of the lensed Hubble Space Telescope near-infrared emission shows two objects which appear to be interacting, with the rotating disc of gas and dust revealed by ALMA distinctly offset from the near-infrared emission. The clumpy nature of the dust and a low value of the Toomre parameter of Q ∼ 0.3 suggest that the disc is in a state of collapse. We estimate a star formation rate in the disc of 470 ± 80 MΘ yr−1 with an efficiency ∼65 times greater than typical low-redshift galaxies. Our findings add to the growing body of evidence that the most infrared luminous, dust obscured galaxies in the high-redshift Universe represent a population of merger-induced starbursts.
| Item Type: |
Article
|
| Additional Information: |
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
| Keywords: |
gravitational lensing: strong, galaxies: structure |
| Schools/Departments: |
University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy |
| Identification Number: |
10.1093/mnras/stv1442 |
| Depositing User: |
Dye, Simon
|
| Date Deposited: |
02 May 2017 10:17 |
| Last Modified: |
12 Oct 2017 22:38 |
| URI: |
https://eprints.nottingham.ac.uk/id/eprint/42260 |
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