2021ApJ...908...62C

We present the first spectroscopically resolved Hα emission map of the Large Magellanic Cloud's (LMC) galactic wind. By combining new Wisconsin H-alpha Mapper observations (I_Hα >= 10 mR) with existing H I 21 cm emission observations, we (1) mapped the LMC's nearside galactic wind over a local standard of rest (LSR) velocity range of +50 <= v_LSR <= +250 km s^–1, (2) determined its morphology and extent, and (3) estimated its mass, outflow rate, and mass-loading factor. We observe Hα emission from this wind to typically 1° off the LMC's H I disk. Kinematically, we find that the diffuse gas in the warm-ionized phase of this wind persists at both low (<=100 km s^–1) and high (>=100 km s^–1) velocities, relative to the LMC's H I disk. Furthermore, we find that the high-velocity component spatially aligns with the most intense star-forming region, 30 Doradus. We, therefore, conclude that this high-velocity material traces an active outflow. We estimate the mass of the warm (T_e ≃ 10⁴ K) ionized phase of the nearside LMC outflow to be log(M_ionized/M_☉)=7.51±0.15 for the combined low and high-velocity components. Assuming an ionization fraction of 75% and that the wind is symmetrical about the LMC disk, we estimate that its total (neutral and ionized) mass is log(M_total/M_☉)=7.93, its mass-flow rate is {dot}M_outflow~1.43M_☉yr^–1, and its mass-loading factor is η ≃ 4.54. Our average mass-loading factor results are roughly a factor of 2.5 larger than previous Hα imaging and UV absorption line studies, suggesting that those studies are missing nearly half the gas in the outflows.