2020ApJ...896..127K -
Astrophys. J., 896, 127-127 (2020/June-3)
Multiple outflows in the high-mass cluster-forming region G25.82-0.17.
KIM J., KIM M.K., HIROTA T., KIM K.-T., SUGIYAMA K., HONMA M., BYUN D.-Y., OH C., MOTOGI K., KANG J., KIM J., LIU T., HU B., BURNS R.A., CHIBUEZE J.O., MATSUMOTO N. and SUNADA K.
Abstract (from CDS):
We present results of continuum and spectral line observations with Atacama Large Millimeter/submillimeter Array (ALMA) and 22 GHz water (H2O) maser observations using the KVN (Korean VLBI Network) and VERA (VLBI Exploration of Radio Astrometry) array (KaVA) 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 ultracompact H II 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 CH3OH 8–1-70 E line, known to be a Class I CH3OH maser at 229 GHz, is also detected, showing a mixture of thermal and maser emission. Moreover, the H2O masers are distributed in a region ∼0.''25 shifted from G25.82-W1. The CH3OH 224-215 E line shows a compact ringlike 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☉ and the total mass of 20-84 M☉ 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.
Abstract Copyright:
© 2020. The American Astronomical Society. All rights reserved.
Journal keyword(s):
Star formation - Star-forming regions - Circumstellar disks - Stellar jets - Astrophysical masers - Protostars - Young massive clusters - Young stellar objects - Very long baseline interferometry - Radio interferometry
Nomenclature:
Fig. 1, Table 2: [KKH2020] G25.82-WN (Nos G25.82-E, G25.82-W, G25.82-W1 to G25.82-W3).
Simbad objects:
13
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