A study of dynamical processes in the Orion KL region using ALMA--
  Probing molecular outflow and inflow
  This work reports a high spatial resolution observations toward Orion KL
region with high critical density lines of CH$_{3}$CN (12$_{4}$-11$_{4}$) and
CH$_{3}$OH (8$_{-1, 8}$-7$_{0, 7}$) as well as continuum at $\sim$1.3 mm band.
The observations were made using the Atacama Large Millimeter/Submillimeter
Array with a spatial resolution of $\sim$1.5$^{\prime\prime}$ and sensitives
about 0.07 K and $\sim$0.18 K for continuum and line, respectively. The
observational results showed that the gas in the Orion KL region consists of
jet-propelled cores at the ridge and dense cores at east and south of the
region, shaped like a wedge ring. The outflow has multiple lobes, which may
originate from an explosive ejection and is not driven by young stellar
objects. Four infrared bubbles were found in the Spitzer/IRAC emissions. These
bubbles, the distributions of the previously found H$_2$ jets, the young
stellar objects and molecular gas suggested that BN is the explosive center.
The burst time was estimated to be $\leq$ 1300 years. In the mean time,
signatures of gravitational collapse toward Source I and hot core were detected
with material infall velocities of 1.5 km~s$^{-1}$ and $\sim$ 0.6 km~s$^{-1}$,
corresponding to mass accretion rates of 1.2$\times$10$^{-3}$M$_{\sun}$/Yr and
8.0$\times$10$^{-5}$M$_{\sun}$/Yr, respectively. These observations may support
that high-mass stars form via accretion model, like their low-mass
counterparts.
