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DYNAMO - I. A sample of H alpha-luminous galaxies with resolved kinematics

Green, AW and Glazebrook, K and McGregor, PJ and Damjanov, I and Wisnioski, E and Abraham, RG and Colless, M and Sharp, RG and Crain, RA and Poole, GB and McCarthy, PJ (2014) DYNAMO - I. A sample of H alpha-luminous galaxies with resolved kinematics. Monthly Notices of the Royal Astronomical Society, 437 (2). pp. 1070-1095. ISSN 0035-8711

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Abstract

DYNAMO is a multiwavelength, spatially resolved survey of local (z ∼ 0.1) star-forming galaxies designed to study evolution through comparison with samples at z _ 2. Half of the sample has integrated Hα luminosities of >1042 erg s−1, the typical lower limit for resolved spectroscopy at z _ 2. The sample covers a range in stellar mass (109–1011M_) and star formation rate (0.2–100M_ yr−1). In this first paper of a series, we present integral-field spectroscopy of Hα emission for the sample of 67 galaxies. We infer gas fractions in our sample as high as _0.8, higher than typical for local galaxies. Gas fraction correlates with stellarmass in galaxies with star formation rates below 10M_ yr−1, as found by COLDGASS, but galaxies with higher star formation rates have higher than expected gas fractions. There is only a weak correlation, if any, between gas fraction and gas velocity dispersion. Galaxies in the sample visually classified as disc-like are offset from the local stellar mass Tully–Fisher relation to higher circular velocities, but this offset vanishes when both gas and stars are included in the baryonic Tully–Fisher relation. The mean gas velocity dispersion of the sample is_50 km s−1, and V/σ ranges from 2 to 10 for most of the discs, similar to ‘turbulent’ galaxies at high redshift. Half of our sample show disc-like rotation, while ∼20 per cent show no signs of rotation. The division between rotating and non-rotating is approximately equal for the sub-samples with either star formation rates >10M_ yr−1, or specific star formation rates typical of the star formation ‘main sequence’ at z _ 2. Across our whole sample, we find good correlation between the dominance of ‘turbulence’ in galaxy discs (as expressed by V/σ ) and gas fraction as has been predicted for marginally stable Toomre discs. Comparing our sample with many others at low- and high-redshift reveals a correlation between gas velocity dispersion and star formation rate. These findings suggest the DYNAMO discs are excellent candidates for local galaxies similar to turbulent z _ 2 disc galaxies.

Item Type: Article
Additional Information: This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record Andrew W. Green, Karl Glazebrook, Peter J. McGregor, Ivana Damjanov, Emily Wisnioski, Roberto G. Abraham, Matthew Colless, Robert G. Sharp, Robert A. Crain, Gregory B. Poole, and Patrick J. McCarthy. DYNAMO – I. A sample of Hα-luminous galaxies with resolved kinematics. MNRAS (January 11, 2014) Vol. 437 1070-1095 doi:10.1093/mnras/stt1882 first published online November 14, 2013 is available online at: http://dx.doi.org/10.1093/mnras/stt1882
Uncontrolled Keywords: 0201 Astronomical And Space Sciences
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
Related URLs:
Date Deposited: 31 Oct 2016 11:01
Last Modified: 31 Oct 2016 11:01
DOI or Identification number: 10.1093/mnras/stt1882
URI: http://researchonline.ljmu.ac.uk/id/eprint/4696

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