The energetics of starburst-driven outflows at z=1 from KMOS. (arXiv:1906.05311v1 [astro-ph.GA])

The energetics of starburst-driven outflows at z=1 from KMOS. (arXiv:1906.05311v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Swinbank_M/0/1/0/all/0/1">Mark Swinbank</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Harrison_C/0/1/0/all/0/1">Chris Harrison</a> (2,1), <a href="http://arxiv.org/find/astro-ph/1/au:+Tiley_A/0/1/0/all/0/1">Alfie Tiley</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Johnson_H/0/1/0/all/0/1">Helen Johnson</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Smail_I/0/1/0/all/0/1">Ian Smail</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Stott_J/0/1/0/all/0/1">John Stott</a> (3), <a href="http://arxiv.org/find/astro-ph/1/au:+Best_P/0/1/0/all/0/1">Philip Best</a> (6), <a href="http://arxiv.org/find/astro-ph/1/au:+Bower_R/0/1/0/all/0/1">Richard Bower</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Bureau_M/0/1/0/all/0/1">Martin Bureau</a> (4), <a href="http://arxiv.org/find/astro-ph/1/au:+Bunker_A/0/1/0/all/0/1">Andy Bunker</a> (4), <a href="http://arxiv.org/find/astro-ph/1/au:+Cirasuolo_M/0/1/0/all/0/1">Michele Cirasuolo</a> (2), <a href="http://arxiv.org/find/astro-ph/1/au:+Jarvis_M/0/1/0/all/0/1">Matt Jarvis</a> (4), <a href="http://arxiv.org/find/astro-ph/1/au:+Magdis_G/0/1/0/all/0/1">Georgios Magdis</a> (5), <a href="http://arxiv.org/find/astro-ph/1/au:+Sharples_R/0/1/0/all/0/1">Ray Sharples</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Sobral_D/0/1/0/all/0/1">David Sobral</a> (3) (1: Durham, 2: ESO, 3: Lancaster, 4: Oxford, 5: Copenhagen, 6: Edinburgh)

We present an analysis of the gas outflow energetics of 529 main-sequence
star-forming galaxies at z~1 using KMOS observations of the broad, underlying
H-alpha 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
Mo/yr and M* = (1.0+/-0.1)x10^10 Mo respectively, we derive a typical mass
outflow rate of dM/dt = 1-4 Mo/yr and a mass loading of dM/dt/SFR = 0.2–0.4.
The mass loading of the wind does not show a strong trend with star-formation
rate over the range SFR ~ 2–20 Mo/yr, although we identify a trend with
stellar mass such that dM/dt/SFR ~ M*^(0.26+/-0.07). Finally, we find that the
line width of the broad H-alpha increases with disk circular velocity with a
sub-linear scaling relation FWHM_broad ~ v^(0.21+/-0.05). As a result of this
behavior, in the lowest mass galaxies (M* < 10^10 Mo), 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* >
10^10 Mo) most of the gas will be retained, flowing back on to the galaxy disk
at later times.

We present an analysis of the gas outflow energetics of 529 main-sequence
star-forming galaxies at z~1 using KMOS observations of the broad, underlying
H-alpha 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
Mo/yr and M* = (1.0+/-0.1)x10^10 Mo respectively, we derive a typical mass
outflow rate of dM/dt = 1-4 Mo/yr and a mass loading of dM/dt/SFR = 0.2–0.4.
The mass loading of the wind does not show a strong trend with star-formation
rate over the range SFR ~ 2–20 Mo/yr, although we identify a trend with
stellar mass such that dM/dt/SFR ~ M*^(0.26+/-0.07). Finally, we find that the
line width of the broad H-alpha increases with disk circular velocity with a
sub-linear scaling relation FWHM_broad ~ v^(0.21+/-0.05). As a result of this
behavior, in the lowest mass galaxies (M* < 10^10 Mo), 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* >
10^10 Mo) most of the gas will be retained, flowing back on to the galaxy disk
at later times.

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