A Spatially Resolved Study of Cold Dust, Molecular Gas, H II Regions, and Stars in the z = 2.12 Submillimeter Galaxy ALESS67.1
Artikel i vetenskaplig tidskrift, 2017

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 ?m 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 H? 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-? 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.

submillimeter: galaxies

galaxies: formation

cosmology: observations

galaxies: star formation

galaxies: high-redshift

galaxies: evolution


C. C. Chen

European Southern Observatory (ESO)

University of Durham

J. A. Hodge

Leiden University

I. Smail

University of Durham

A. M. Swinbank

University of Durham

F. Walter

Max Planck-institutet

J. M. Simpson

Academia Sinica

Gabriela Calistro Rivera

Leiden University

F. Bertoldi

Universität Bonn

W. N. Brandt

Pennsylvania State University

S. C. Chapman

Dalhousie University

E. da Cunha

Australian National University

H. Dannerbauer

Universidad de la Laguna

Instituto Astrofisico de Canarias

C. Da Breuck

European Southern Observatory (ESO)

C. M. Harrison

European Southern Observatory (ESO)

R. J. Ivison

University of Edinburgh

European Southern Observatory (ESO)

A. Karim

Universität Bonn

Kirsten Kraiberg Knudsen

Astronomi och plasmafysik

J. L. Wardlow

University of Durham

A. Weiß

Max Planck-institutet

P. van der Werf

Leiden University

Astrophysical Journal

0004-637X (ISSN) 1538-4357 (eISSN)

Vol. 846 108


Astronomi, astrofysik och kosmologi