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LHA 115-N 83 (N83) and LHA 115-N 84 (N84) are HII regions associated with theearly stage of star formation located in the Small Magellanic Cloud (SMC). Wehave analyzed the new HI data taken with the Galactic Australian SquareKilometre Array Pathfinder survey project at a high angular resolution of 30".We found that the two clouds, having $\sim$40 km s$^{-1}$ velocity separation,show complementary distribution with each other, and part of the HI gas isdispersed by the ionization. In addition, the Atacama LargeMillimeter/submillimeter Array observations revealed clumpy CO clouds of10$^{5}$ $M_{\odot}$ in total over an extent of 100 pc, which are also wellcorrelated with the HII regions. There is a hint of displacement between thetwo complementary components, which indicate that the red-shifted HI cloud ismoving from the north to the south by $\sim$100 pc. This motion is similar towhat is found in NGC 602 (Fukui et al. 2020), suggesting a large scalesystematic gas flow. We frame a scenario that the two components collided witheach other and triggered the formation of N83, N84, and six O-type stars aroundthem in a time scale of a few Myr ($\sim$60 pc / 40 km s$^{-1}$). Thesupersonic motion compressed the HI gas to form the CO clouds in thered-shifted HI cloud, some of which are forming O-type stars ionizing the HIIregions in the last Myr. The red-shifted HI cloud probably flows to thedirection of the Magellanic Bridge. The velocity field originated by the closeencounter of the SMC with the Large Magellanic Cloud 200 Myr ago as proposed byFujimoto & Noguchi (1990).

The formation of the HII regions N83 and N84 in the Small Magellanic Cloud triggered by colliding HI flows