J Molina
The kiloparsec-scale gas kinematics in two star-forming galaxies at z ∼ 1.47 seen with ALMA and VLT-SINFONI
Molina, J; Ibar, Edo; Smail, I; Swinbank, AM; Villard, E; Escala, A; Sobral, D; Hughes, TM
Authors
Edo Ibar
Professor Ian Smail ian.smail@durham.ac.uk
Emeritus Professor
Professor Mark Swinbank a.m.swinbank@durham.ac.uk
Professor
E Villard
A Escala
D Sobral
TM Hughes
Abstract
We present Atacama Large Millimeter/submillimeter Array (ALMA) CO(J = 2 − 1) observations of two main-sequence star-forming galaxies at z ∼ 1.47 taken from the High-Z Emission Line Survey (HiZELS). These two systems have been previously reported to be molecular gas rich fH2≡MH2/(MH2+M⋆)∼0.8. We carried out a follow-up study to resolve, at ∼kpc-scales, the CO emission. These new observations are combined with our earlier ALMA observations (sensitive to diffuse CO emission) and compared with our previous Hα-based study at matched spatial resolution. One target is marginally resolved in CO(2-1), showing complex dynamics with respect to the ionised gas traced by Hα. While the other source is spatially resolved, enabling a detailed exploration of its internal dynamical properties. In this system, both gaseous phases show similar spatial extension, rotation velocities and velocity dispersions (Vrot ∼ σv ∼ 100 km s−1) suggesting a rotational velocity to velocity dispersion ratio consistent with unity. By comparing the ionized and molecular gas tracers through the use of a two-dimensional kinematic model, we estimate a median depletion time τdep = 2.3 ± 1.2 Gyr for the galaxy as a whole. This value is in agreement with the average τdep value observed in local star-forming galaxies at similar spatial scales. Using a thick-disk dynamical modelling, we derive a dynamical mass Mdyn = (1.59 ± 0.19) × 1011 M⊙ within ≈6 kpc. This suggests a dark matter fraction (fDM ≡ MDM/Mdyn of 0.59 ± 0.10, in agreement with the average fDM value derived from stacked rotation curve analysis of galaxies at similar redshift range.
Journal Article Type | Article |
---|---|
Acceptance Date | Jun 8, 2019 |
Online Publication Date | Jun 13, 2019 |
Publication Date | Aug 31, 2019 |
Deposit Date | Jun 14, 2019 |
Publicly Available Date | Jun 14, 2019 |
Journal | Monthly Notices of the Royal Astronomical Society |
Print ISSN | 0035-8711 |
Electronic ISSN | 1365-2966 |
Publisher | Royal Astronomical Society |
Peer Reviewed | Peer Reviewed |
Volume | 487 |
Issue | 4 |
Pages | 4856-4869 |
DOI | https://doi.org/10.1093/mnras/stz1643 |
Public URL | https://durham-repository.worktribe.com/output/1299702 |
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Copyright Statement
© 2019 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.
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