Multiple outflows in the high-mass cluster forming region, G25.82-0.17. (arXiv:2005.05006v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Kim_J/0/1/0/all/0/1">Jungha Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_M/0/1/0/all/0/1">Mi Kyoung Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hirota_T/0/1/0/all/0/1">Tomoya Hirota</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_K/0/1/0/all/0/1">Kee-Tae Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sugiyama_K/0/1/0/all/0/1">Koichiro Sugiyama</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Honma_M/0/1/0/all/0/1">Mareki Honma</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Byun_D/0/1/0/all/0/1">Do-young Byun</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Oh_C/0/1/0/all/0/1">Chungsik Oh</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Motogi_K/0/1/0/all/0/1">Kazuhito Motogi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kang_J/0/1/0/all/0/1">Jihyun Kang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Kim_J/0/1/0/all/0/1">Jeongsook Kim</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liu_T/0/1/0/all/0/1">Tie Liu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Hu_B/0/1/0/all/0/1">Bo Hu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Burns_R/0/1/0/all/0/1">Ross A. Burns</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Chibueze_J/0/1/0/all/0/1">James O. Chibueze</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Matsumoto_N/0/1/0/all/0/1">Naoko Matsumoto</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Sunada_K/0/1/0/all/0/1">Kazuyoshi Sunada</a>
We present results of continuum and spectral line observations with ALMA and
22 GHz water (H$_2$O) maser observations using KaVA and VERA toward a high-mass
star-forming region, G25.82-0.17. Multiple 1.3 mm continuum sources are
revealed, indicating the presence of young stellar objects (YSOs) at different
evolutionary stages, namely an ultra-compact HII region, G25.82-E, a high-mass
young stellar object (HM-YSO), G25.82-W1, and starless cores, G25.82-W2 and
G25.82-W3. Two SiO outflows, at N-S and SE-NW orientations, are identified. The
CH$_3$OH 8$_{-1}$-7$_{0}$ E line, known to be a class I CH$_3$OH maser at 229
GHz is also detected showing a mixture of thermal and maser emission. Moreover,
the H$_2$O masers are distributed in a region ~0.25″ shifted from G25.82-W1.
The CH$_3$OH 22$_{4}$-21$_{5}$ E line shows a compact ring-like structure at
the position of G25.82-W1 with a velocity gradient, indicating a rotating disk
or envelope. Assuming Keplerian rotation, the dynamical mass of G25.82-W1 is
estimated to be $>$25 M$_{odot}$ and the total mass of 20 M$_odot$-84
M$_odot$ is derived from the 1.3 mm continuum emission. The driving source of
the N-S SiO outflow is G25.82-W1 while that of the SE-NW SiO outflow is
uncertain. Detection of multiple high-mass starless$/$protostellar cores and
candidates without low-mass cores implies that HM-YSOs could form in individual
high-mass cores as predicted by the turbulent core accretion model. If this is
the case, the high-mass star formation process in G25.82 would be consistent
with a scaled-up version of low-mass star formation.
We present results of continuum and spectral line observations with ALMA and
22 GHz water (H$_2$O) maser observations using KaVA and VERA toward a high-mass
star-forming region, G25.82-0.17. Multiple 1.3 mm continuum sources are
revealed, indicating the presence of young stellar objects (YSOs) at different
evolutionary stages, namely an ultra-compact HII region, G25.82-E, a high-mass
young stellar object (HM-YSO), G25.82-W1, and starless cores, G25.82-W2 and
G25.82-W3. Two SiO outflows, at N-S and SE-NW orientations, are identified. The
CH$_3$OH 8$_{-1}$-7$_{0}$ E line, known to be a class I CH$_3$OH maser at 229
GHz is also detected showing a mixture of thermal and maser emission. Moreover,
the H$_2$O masers are distributed in a region ~0.25″ shifted from G25.82-W1.
The CH$_3$OH 22$_{4}$-21$_{5}$ E line shows a compact ring-like structure at
the position of G25.82-W1 with a velocity gradient, indicating a rotating disk
or envelope. Assuming Keplerian rotation, the dynamical mass of G25.82-W1 is
estimated to be $>$25 M$_{odot}$ and the total mass of 20 M$_odot$-84
M$_odot$ is derived from the 1.3 mm continuum emission. The driving source of
the N-S SiO outflow is G25.82-W1 while that of the SE-NW SiO outflow is
uncertain. Detection of multiple high-mass starless$/$protostellar cores and
candidates without low-mass cores implies that HM-YSOs could form in individual
high-mass cores as predicted by the turbulent core accretion model. If this is
the case, the high-mass star formation process in G25.82 would be consistent
with a scaled-up version of low-mass star formation.
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