TY - JOUR

T1 - The energetics of starburst-driven outflows at z ∼ 1 from KMOS

AU - Swinbank, A. M.

AU - Harrison, Chris M.

AU - Tiley, Alfred L.

AU - Johnson, Helen L.

AU - Smail, Ian

AU - Stott, John

AU - Best, Philip N.

AU - Bower, Richard

AU - Bureau, Martin

AU - Cirasuolo, M.

AU - Jarvis, Matt

AU - Magdis, Georgios E.

AU - Sharples, Ray M.

AU - Sobral, David

N1 - This is a pre-copy-editing, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The definitive publisher-authenticated version A M Swinbank, C M Harrison, A L Tiley, H L Johnson, Ian Smail, J P Stott, P N Best, R G Bower, M Bureau, A Bunker, M Cirasuolo, M Jarvis, G E Magdis, R M Sharples, D Sobral, The energetics of starburst-driven outflows at z ∼ 1 from KMOS, Monthly Notices of the Royal Astronomical Society, Volume 487, Issue 1, July 2019, Pages 381–393 is available online at: https://academic.oup.com/mnras/article/487/1/381/5487523

PY - 2019/7/1

Y1 - 2019/7/1

N2 - 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 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 = 7 M⊙ / yr and M⋆ = (1.0 ± 0.1) × 1010 M⊙ respectively, we derive a typical mass outflow rate of \dot{M}_wind = 1-4 M⊙ yr-1 and a mass loading of \dot{M}_wind / 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 ɛ ˜ 0.03. The mass loading of the wind does not show a strong trend with star-formation rate over the range ˜ 2-20 M⊙ yr-1, although we identify a trend with stellar mass such that dM / dt / SFR ∝ M_\star ^{0.26± 0.07}. Finally, the line width of the broad Hα increases with disk circular velocity with a sub-linear scaling relation FWHMbroad ∝ v0.21 ± 0.05. As a result of this behavior, in the lowest mass galaxies (M_\star ≲10^{10} M⊙), 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_\star ≳10^{10} M⊙) most of the gas will be retained, flowing back on to the galaxy disk at later times.

AB - 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 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 = 7 M⊙ / yr and M⋆ = (1.0 ± 0.1) × 1010 M⊙ respectively, we derive a typical mass outflow rate of \dot{M}_wind = 1-4 M⊙ yr-1 and a mass loading of \dot{M}_wind / 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 ɛ ˜ 0.03. The mass loading of the wind does not show a strong trend with star-formation rate over the range ˜ 2-20 M⊙ yr-1, although we identify a trend with stellar mass such that dM / dt / SFR ∝ M_\star ^{0.26± 0.07}. Finally, the line width of the broad Hα increases with disk circular velocity with a sub-linear scaling relation FWHMbroad ∝ v0.21 ± 0.05. As a result of this behavior, in the lowest mass galaxies (M_\star ≲10^{10} M⊙), 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_\star ≳10^{10} M⊙) most of the gas will be retained, flowing back on to the galaxy disk at later times.

M3 - Journal article

VL - 487

SP - 381

EP - 393

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 1

ER -