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A Spatially Resolved Study of Cold Dust, Molecular Gas, H II Regions, and Stars in the z = 2.12 Submillimeter Galaxy ALESS67.1

Lookup NU author(s): Dr Christopher HarrisonORCiD



This is the final published version of an article that has been published in its final definitive form by Institute of Physics Publishing, 2017.

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© 2017. The American Astronomical Society. All rights reserved. We present detailed studies of a z = 2.12 submillimeter galaxy, ALESS67.1, using sub-arcsecond resolution ALMA, adaptive optics-aided VLT/SINFONI, and Hubble Space Telescope (HST)/CANDELS data to investigate the kinematics and spatial distributions of dust emission (870 μm continuum), 12CO(J = 3-2), strong optical emission lines, and visible stars. Dynamical modeling of the optical emission lines suggests that ALESS67.1 is not a pure rotating disk but a merger, consistent with the apparent tidal features revealed in the HST imaging. Our sub-arcsecond resolution data set allows us to measure half-light radii for all the tracers, and we find a factor of 4-6 smaller sizes in dust continuum compared to all the other tracers, including 12CO; also, ultraviolet (UV) and Hα emission are significantly offset from the dust continuum. The spatial mismatch between the UV continuum and the cold dust and gas reservoir supports the explanation that geometrical effects are responsible for the offset of the dusty galaxy on the IRX-β diagram. Using a dynamical method we derive an , consistent with other submillimeter galaxies (SMGs) that also have resolved CO and dust measurements. Assuming a single value we also derive resolved gas and star formation rate surface densities, and find that the core region of the galaxy ( kpc) follows the trend of mergers on the Schmidt-Kennicutt relationship, whereas the outskirts ( kpc) lie on the locus of normal star-forming galaxies, suggesting different star formation efficiencies within one galaxy. Our results caution against using single size or morphology for different tracers of the star formation activity and gas content of galaxies, and therefore argue the need to use spatially resolved, multi-wavelength observations to interpret the properties of SMGs, and perhaps even for galaxies in general.

Publication metadata

Author(s): Chen C-C, Hodge JA, Smail I, Swinbank AM, Walter F, Simpson JM, Rivera GC, Bertoldi F, Brandt WN, Chapman SC, Da Cunha E, Dannerbauer H, Da Breuck C, Harrison CM, Ivison RJ, Karim A, Knudsen KK, Wardlow JL, Weiss A, Van Der Werf P

Publication type: Article

Publication status: Published

Journal: Astrophysical Journal

Year: 2017

Volume: 846

Issue: 2

Online publication date: 07/09/2017

Acceptance date: 03/08/2017

Date deposited: 05/02/2020

ISSN (print): 0004-637X

ISSN (electronic): 1538-4357

Publisher: Institute of Physics Publishing


DOI: 10.3847/1538-4357/aa863a


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