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The energetics of starburst-driven outflows at z ∼1 from KMOS

Lookup NU author(s): Dr Christopher HarrisonORCiD



This is the final published version of an article that has been published in its final definitive form by Oxford University Press, 2019.

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© 2018 The Author(s).We present an analysis of the gas outflow energetics from KMOS observations of ∼529 mainsequence star-forming galaxies at z ∼1 using broad, underlying Hα and forbidden lines of [N II] and [S II]. Based on the stacked spectra for a sample with median star-formation rates and stellar masses of SFR = 7Ṁ yr-1 and M∗ = (1.0±0.1) × 1010Ṁ, respectively, we derive a typical mass outflow rate of Mwind = 1-4Ṁ yr-1 and a mass loading of Mwind / SFR = 0.2- 0.4. By comparing the kinetic energy in the wind with the energy released by supernovae, we estimate a coupling efficiency between the star formation and wind energetics of ∈ ∼ 0.03. The mass loading of the wind does not show a strong trend with star-formation rate over the range ∼2-20Ṁ yr-1, although we identify a trend with stellar mass such that dM/ dt / SFR ∝ M0.26±0.07. Finally, the line width of the broad Hα increases with disc circular velocity with a sub-linear scaling relation FWHMbroad ∝ v0.21 ± 0.05. As a result of this behaviour, in the lowest mass galaxies (M∗≲ 1010Ṁ), a significant fraction of the outflowing gas should have sufficient velocity to escape the gravitational potential of the halo whilst in the highest mass galaxies (M∗≲ 1010Ṁ) most of the gas will be retained, flowing back on to the galaxy disc at later times.

Publication metadata

Author(s): Swinbank AM, Harrison CM, Tiley AL, Johnson HL, Smail I, Stott JP, Best PN, Bower RG, Bureau M, Bunker A, Cirasuolo M, Jarvis M, Magdis GE, Sharples RM, Sobral D

Publication type: Article

Publication status: Published

Journal: Monthly Notices of the Royal Astronomical Society

Year: 2019

Volume: 487

Issue: 1

Pages: 381-393

Print publication date: 01/07/2019

Online publication date: 09/05/2019

Acceptance date: 02/05/2019

Date deposited: 04/02/2020

ISSN (print): 0035-8711

ISSN (electronic): 1365-2966

Publisher: Oxford University Press


DOI: 10.1093/mnras/stz1275


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