From peculiar morphologies to hubble-type spirals: The relation between galaxy dynamics and morphology in star-forming galaxies at z ∼ 1.5

S. Gillman, A. L. Tiley, A. M. Swinbank, C. M. Harrison, Ian Smail, U. Dudzevǐciute, R. M. Sharples, L. Cortese, D. Obreschkow, R. G. Bower, T. Theuns, M. Cirasuolo, D. B. Fisher, K. Glazebrook, Edo Ibar, J. Trevor Mendel, Sarah M. Sweet

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

We present an analysis of the gas dynamics of star-forming galaxies at z ∼ 1.5 using data from the KMOS Galaxy Evolution Survey. We quantify the morphology of the galaxies using HST CANDELS imaging parametrically and non-parametrically. We combine the Hα dynamics from KMOS with the high-resolution imaging to derive the relation between stellar mass (M*) and stellar specific angular momentum (j).We showthat high-redshift star-forming galaxies at z∼1.5 followa power-lawtrend in specific stellar angular momentum with stellarmass similar to that of local late-type galaxies of the form j ∝ M0.53±0.10 . The highest specific angular momentum galaxies are mostly disc-like, although generally both peculiar morphologies and disc-like systems are found across the sequence of specific angular momentum at a fixed stellar mass.We explore the scatterwithin the j-M plane and its correlationwith both the integrated dynamical properties of a galaxy (e.g. velocity dispersion, Toomre Qg, Hα star formation rate surface density-SFR) and its parametrized rest-frame UV/optical morphology (e.g. Sérsic index, bulge to total ratio, clumpiness, asymmetry, and concentration). We establish that the position in the j-M plane is strongly correlated with the star-formation surface density and the clumpiness of the stellar light distribution. Galaxies with peculiar rest-frame UV/optical morphologies have comparable specific angular momentum to disc-dominated galaxies of the same stellar mass, but are clumpier and have higher star formation rate surface densities. We propose that the peculiar morphologies in high-redshift systems are driven by higher star formation rate surface densities and higher gas fractions leading to a more clumpy interstellar medium. 2019 The Author(s).

Original languageEnglish
Pages (from-to)1492-1512
Number of pages21
JournalMonthly Notices of the Royal Astronomical Society
Volume492
Issue number1
DOIs
Publication statusPublished - 1 Feb 2020

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