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

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

doi:10.1093/mnras/stz1275

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

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

Authors

Professor Mark Swinbank a.m.swinbank@durham.ac.uk
Professor

C.M. Harrison

A.L. Tiley

H.L. Johnson

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

J.P. Stott

P.N. Best

R.G. Bower

M. Bureau

A. Bunker

M. Cirasuolo

M. Jarvis

G.E. Magdis

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

D. Sobral

Abstract

We present an analysis of the gas outflow energetics from KMOS observations of 529 main-sequence star-forming galaxies at z 1 using broad, underlying Hα and forbid- den lines of [Nii] and [Sii]. Based on the stacked spectra for a sample with median star- formation rates and stellar masses of SFR=7M⊙ / yr and M⋆ =(1.0±0.1)×1010M⊙ respectively, we derive a typical mass outflow rate of ˙Mwind =1–4M⊙ 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 ǫ 0.03. The mass loading of the wind does not show a strong trend with star-formation rate over the range 2–20M⊙ 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 disk circular velocity with a sub-linear scal- ing relation FWHMbroad /v0.21±0.05. As a result of this behavior, in the lowest mass galaxies (M⋆ < ∼ 1010M⊙), a significant fraction of the outflowing gas should have suf- ficient velocity to escape the gravitational potential of the halo whilst in the highest mass galaxies (M⋆ > ∼ 1010M⊙) most of the gas will be retained, flowing back on to the galaxy disk at later times.

Citation

Swinbank, A., Harrison, C., Tiley, A., Johnson, H., Smail, I., Stott, J., …Sobral, D. (2019). The energetics of starburst-driven outflows at z ∼ 1 from KMOS. Monthly Notices of the Royal Astronomical Society, 487(1), 381-393. https://doi.org/10.1093/mnras/stz1275

Journal Article Type	Article
Acceptance Date	May 2, 2019
Online Publication Date	May 9, 2019
Publication Date	Jul 31, 2019
Deposit Date	May 17, 2019
Publicly Available Date	May 17, 2019
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	487
Issue	1
Pages	381-393
DOI	https://doi.org/10.1093/mnras/stz1275