The KMOS Redshift One Spectroscopic Survey (KROSS): rotational velocities and angular momentum of z ≈ 0.9 galaxies

Harrison, C.M.; Johnson, H.L.; Swinbank, A.M.; Stott, J.P.; Bower, R.G.; Smail, I.; Tiley, A.L.; Bunker, A.J.; Cirasuolo, M.; Sobral, D.; Sharples, R.M.; Best, P.; Bureau, M.; Jarvis, M.J.; Magdis, G.

doi:10.1093/mnras/stx217

The KMOS Redshift One Spectroscopic Survey (KROSS): rotational velocities and angular momentum of z ≈ 0.9 galaxies

Harrison, C.M.; Johnson, H.L.; Swinbank, A.M.; Stott, J.P.; Bower, R.G.; Smail, I.; Tiley, A.L.; Bunker, A.J.; Cirasuolo, M.; Sobral, D.; Sharples, R.M.; Best, P.; Bureau, M.; Jarvis, M.J.; Magdis, G.

Authors

C.M. Harrison

H.L. Johnson

A.M. Swinbank

J.P. Stott

R.G. Bower

Professor Ian Smail ian.smail@durham.ac.uk
Emeritus Professor

A.L. Tiley

A.J. Bunker

M. Cirasuolo

D. Sobral

Professor Ray Sharples r.m.sharples@durham.ac.uk
Professor

P. Best

M. Bureau

M.J. Jarvis

G. Magdis

Abstract

We present dynamical measurements for 586 Hα detected star-forming galaxies from the KMOS (K-band Multi-Object Spectrograph) Redshift One Spectroscopic Survey (KROSS). The sample represents typical star-forming galaxies at this redshift (z = 0.6–1.0), with a median star formation rate of ≈7 M⊙ yr−1 and a stellar mass range of log (M⋆[M⊙])≈9–11. We find that the rotation velocity-stellar mass relationship (the inverse of the Tully-Fisher relationship) for our rotationally-dominated sources (VC/σ0 > 1) has a consistent slope and normalisation as that observed for z = 0 disks. In contrast, the specific angular momentum (j⋆; angular momentum divided by stellar mass), is ≈0.2–0.3 dex lower on average compared to z = 0 disks. The specific angular momentum scales as j s ∝M 0.6±0.2 ⋆ js∝M⋆0.6±0.2 , consistent with that expected for dark matter (i.e., j DM ∝M 2/3 DM jDM∝MDM2/3 ). We find that z ≈ 0.9 star-forming galaxies have decreasing specific angular momentum with increasing Sérsic index. Visually, the sources with the highest specific angular momentum, for a given mass, have the most disk-dominated morphologies. This implies that an angular momentum–mass–morphology relationship, similar to that observed in local massive galaxies, is already in place by z ≈ 1.

Citation

Harrison, C., Johnson, H., Swinbank, A., Stott, J., Bower, R., Smail, I., …Magdis, G. (2017). The KMOS Redshift One Spectroscopic Survey (KROSS): rotational velocities and angular momentum of z ≈ 0.9 galaxies. Monthly Notices of the Royal Astronomical Society, 467(2), 1965-1983. https://doi.org/10.1093/mnras/stx217

Journal Article Type	Article
Acceptance Date	Jan 23, 2017
Online Publication Date	Feb 7, 2017
Publication Date	May 21, 2017
Deposit Date	Feb 2, 2017
Publicly Available Date	Mar 13, 2017
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	467
Issue	2
Pages	1965-1983
DOI	https://doi.org/10.1093/mnras/stx217
Related Public URLs	https://arxiv.org/pdf/1701.05561v2.pdf

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Copyright 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.