An ALMA view of molecular filaments in the Large Magellanic Cloud II: An early stage of high-mass star formation embedded at colliding clouds in N159W-South. (arXiv:1811.04400v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Tokuda_K/0/1/0/all/0/1">Kazuki Tokuda</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fukui_Y/0/1/0/all/0/1">Yasuo Fukui</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Harada_R/0/1/0/all/0/1">Ryohei Harada</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Saigo_K/0/1/0/all/0/1">Kazuya Saigo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tachihara_K/0/1/0/all/0/1">Kengo Tachihara</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Tsuge_K/0/1/0/all/0/1">Kisetsu Tsuge</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Inoue_T/0/1/0/all/0/1">Tsuyoshi Inoue</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Torii_K/0/1/0/all/0/1">Kazufumi Torii</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nishimura_A/0/1/0/all/0/1">Atsushi Nishimura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zahorecz_S/0/1/0/all/0/1">Sarolta Zahorecz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Nayak_O/0/1/0/all/0/1">Omnarayani Nayak</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Meixner_M/0/1/0/all/0/1">Margaret Meixner</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Minamidani_T/0/1/0/all/0/1">Tetsuhiro Minamidani</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kawamura_A/0/1/0/all/0/1">Akiko Kawamura</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Mizuno_N/0/1/0/all/0/1">Norikazu Mizuno</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Indebetouw_R/0/1/0/all/0/1">Remy Indebetouw</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sewilo_M/0/1/0/all/0/1">Marta Sewiło</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Madden_S/0/1/0/all/0/1">Suzanne Madden</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Galametz_M/0/1/0/all/0/1">Maud Galametz</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Lebouteiller_V/0/1/0/all/0/1">Vianney Lebouteiller</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chen_C/0/1/0/all/0/1">C.-H. Rosie Chen</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Onishi_T/0/1/0/all/0/1">Toshikazu Onishi</a>
We have conducted ALMA CO isotopes and 1.3 mm continuum observations toward
filamentary molecular clouds of the N159W-South region in the Large Magellanic
Cloud with an angular resolution of $sim$0.”25 ($sim$0.07 pc). Although the
previous lower resolution ($sim$1″) ALMA observations revealed that there is a
high-mass protostellar object at an intersection of two linear-shaped filaments
in $^{13}$CO with the length scale of $sim$10 pc (Fukui et al. 2015), the
spatially resolved observations, in particular, toward the highest column
density part traced by the 1.3 mm continuum emission, the N159W-South clump,
show complicated hub-filamentary structures. We also discovered that there are
multiple protostellar sources with bipolar outflows along the massive filament.
The redshifted/blueshifted components of the $^{13}$CO emission around the
massive filaments/protostars show complementary distributions to each other,
which is considered to be a possible piece of evidence for a cloud-cloud
collision. We propose a new scenario that the supersonically colliding gas flow
triggered the formation of both the massive filament and protostars. This is a
modification of the earlier scenario of cloud-cloud collision which postulated
the two filamentary clouds prior to the high-mass star formation by Fukui et
al. (2015). A recent theoretical study of the shock compression in colliding
molecular flows by Inoue et al. (2018) demonstrates that the formation of
filaments with hub-structure is a usual outcome of the collision, lending
support for the present scenario. In the theory the filaments are formed as
dense parts in a shock compressed sheet-like layer, which resembles “an
umbrella with pokes”.
We have conducted ALMA CO isotopes and 1.3 mm continuum observations toward
filamentary molecular clouds of the N159W-South region in the Large Magellanic
Cloud with an angular resolution of $sim$0.”25 ($sim$0.07 pc). Although the
previous lower resolution ($sim$1″) ALMA observations revealed that there is a
high-mass protostellar object at an intersection of two linear-shaped filaments
in $^{13}$CO with the length scale of $sim$10 pc (Fukui et al. 2015), the
spatially resolved observations, in particular, toward the highest column
density part traced by the 1.3 mm continuum emission, the N159W-South clump,
show complicated hub-filamentary structures. We also discovered that there are
multiple protostellar sources with bipolar outflows along the massive filament.
The redshifted/blueshifted components of the $^{13}$CO emission around the
massive filaments/protostars show complementary distributions to each other,
which is considered to be a possible piece of evidence for a cloud-cloud
collision. We propose a new scenario that the supersonically colliding gas flow
triggered the formation of both the massive filament and protostars. This is a
modification of the earlier scenario of cloud-cloud collision which postulated
the two filamentary clouds prior to the high-mass star formation by Fukui et
al. (2015). A recent theoretical study of the shock compression in colliding
molecular flows by Inoue et al. (2018) demonstrates that the formation of
filaments with hub-structure is a usual outcome of the collision, lending
support for the present scenario. In the theory the filaments are formed as
dense parts in a shock compressed sheet-like layer, which resembles “an
umbrella with pokes”.
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