Swinbank, M. and Harrison, C. and Trayford, J. and Schaller, M. and Smail, I. and Schaye, J. and Theuns, T. and Smit, R. and Alexander, D. and Bacon, R. and Bower, R. and Contini, T. and Crain, R. and de Breuck, C. and Decarli, R. and Epinat, B. and Fumagalli, M. and Furlong, M. and Galametz, A. and Johnson, H.L. and Lagos, C. and Richard, J. and Vernet, J. and Sharples, R. and Sobral, D. and Stott, J.P. (2017) 'Angular momentum evolution of galaxies over the past 10 Gyr : a MUSE and KMOS dynamical survey of 400 star-forming galaxies from z = 0.3 to 1.7.', Monthly notices of the Royal Astronomical Society., 467 (3). pp. 3140-3159.
We present a MUSE and KMOS dynamical study 405 star-forming galaxies at redshift z = 0.28–1.65 (median redshift z¯= 0.84). Our sample is representative of the star-forming “main-sequence”, with star-formation rates of SFR = 0.1–30M⊙ yr−1 and stellar masses M⋆ = 108–1011 M⊙. For 49 ± 4% of our sample, the dynamics suggest rotational support, 24 ± 3% are unresolved systems and 5 ± 2% appear to be early-stage major mergers with components on 8–30 kpc scales. The remaining 22 ± 5% appear to be dynamically complex, irregular (or face-on systems). For galaxies whose dynamics suggest rotational support, we derive inclination corrected rotational velocities and show these systems lie on a similar scaling between stellar mass and specific angular momentum as local spirals with j⋆ = J /M⋆ ∝ M 2/3 ⋆ but with a redshift evolution that scales as j⋆ ∝ M 2/3 ⋆ (1 + z) −1 . We also identify a correlation between specific angular momentum and disk stability such that galaxies with the highest specific angular momentum (log(j⋆ / M2/3 ⋆ ) > 2.5) are the most stable, with Toomre Q = 1.10 ± 0.18, compared to Q = 0.53± 0.22 for galaxies with log(j⋆ / M2/3 ⋆ ) < 2.5. At a fixed mass, the HST morphologies of galaxies with the highest specific angular momentum resemble spiral galaxies, whilst those with low specific angular momentum are morphologically complex and dominated by several bright star-forming regions. This suggests that angular momentum plays a major role in defining the stability of gas disks: at z ∼ 1, massive galaxies that have disks with low specific angular momentum, are globally unstable, clumpy and turbulent systems. In contrast, galaxies with high specific angular have evolved in to stable disks with spiral structure where star formation is a local (rather than global) process.
|Full text:||(AM) Accepted Manuscript|
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|Publisher Web site:||https://doi.org/10.1093/mnras/stx201|
|Publisher statement:||This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.|
|Date accepted:||24 January 2017|
|Date deposited:||13 February 2017|
|Date of first online publication:||25 January 2017|
|Date first made open access:||13 March 2017|
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