SF-03-0027

ALMA resolved views of molecular filaments/clumps in the Large Magellanic Cloud: A possible gas flow penetrating one of the most massive protocluster systems in the Local Group

Kazuki Tokuda, Yasuo Fukui, Toshikazu Onishi, Tsuyoshi Inoue, Kisetsu Tsuge, Sarolta Zahorecz, Hidetoshi Sano, Ayu Konishi, Rosie C.-H. Chen, Marta Sewi?o, Suzanne C. Madden, Omnarayani Nayak, Kazuya Saigo, Atsushi Nishimura, Kei E. I. Tanaka, Tsuyoshi Sawada, Remy Indebetouw, Kengo Tachihara, Akiko Kawamura, Margaret Meixner, Tetsuhiro Minamidani, Norikazu Mizuno, Vianney Lebouteiller

We present spatially resolved ALMA observations of molecular filaments in the high-mass star-forming regions N159E-Papillon, W-South, and W-North in the Large Magellanic Cloud (LMC). The N159 region is part of one of the largest giant molecular clouds in the LMC and is an important target for studying the early stages of massive cluster formation. Our CO isotope and 1.3 mm continuum observations with an angular resolution of ~0."25 revealed the presence of impressive hub-filament systems with a typical filament width of ~0.1 pc. These observations discovered embedded high-mass protostars with molecular outflows along massive filaments/clumps, with estimated dynamical times between 1e4 and 1e5 years. These protostellar objects are typically found in a few numbers within each filament or clump, which are separated by a projected distance of ~50 pc. The most massive clump in the observed regions, N159W-North MMS-2, is particularly dense, with a total H2 mass of ~1e4 M_sun and a peak column density of ~1e24 cm^-2. This clump harbors several massive starless-core candidates with masses of ~100 M_sun. CO(1-0) data at a 1" resolution covering the entire molecular cloud revealed a cone-shaped structure extending 30 pc to the north. These observations suggest that a large-scale gas compression event may have facilitated the formation of the massive star-forming complex.
We propose a teardrop inflow model to explain the synchronized and extreme star formation that occurs over a span of about 50 pc, including one of the most massive protocluster clumps in the Local Group. This inflow is driven by the tidal interaction between the LMC and the SMC (Fukui et al. 2017), and is consistent with recent MHD simulations (Inoue et al. 2018) that predict the synchronized formation of the most massive star in the hub, as well as additional star formation along the dense filaments and clumps.