Outflows in Star-forming Galaxies: Stacking Analyses of Resolved Winds
  and the Relation to Their Hosts' Properties
  Outflows form an integral component in regulating the gas cycling in and out
of galaxies, although their impact on the galaxy hosts is still poorly
understood. Here we present an analysis of 405 high mass (log
M$_{*}$/M$_{\odot}\geqslant10$), star-forming galaxies (excluding AGN) with low
inclinations at $z\sim$0, using stacking techniques of the NaD
$\lambda\lambda$5889,5895 A neutral gas tracer in IFU observations from the
MaNGA DR15 survey. We detect outflows in the central regions of 78/405 galaxies
and determine their extent and power through the construction of stacked
annuli. We find outflows are most powerful in central regions and extend out to
$\sim$1R$_{e}$, with declining mass outflow rates and loading factors as a
function of radius. The stacking of spaxels over key galaxy quantities reveals
outflow detections in regions of high $\Sigma_{\text{SFR}}$ ($\gtrsim$0.01
M$_{\odot}$yr$^{-1}$kpc$^{-2}$) and $\Sigma_{M_{*}}$ ($\gtrsim$10$^{7}$
M$_{\odot}$kpc$^{-2}$) along the resolved main sequence. Clear correlations
with $\Sigma_{\text{SFR}}$ suggest it is the main regulator of outflows, with a
critical threshold of $\sim$0.01 M$_{\odot}$yr$^{-1}$kpc$^{-2}$ needed to
escape the weight of the disk and launch them. Furthermore, measurements of the
H$\delta$ and D$_{n}$4000 indices reveal virtually identical star formation
histories between galaxies with outflows and those without. Finally, through
stacking of HI 21 cm observations for a subset of our sample, we find outflow
galaxies show reduced HI gas fractions at central velocities compared to their
non-detection control counterparts, suggestive of some removal of HI gas,
likely in the central regions of the galaxies, but not enough to completely
quench the host.
