English

Multiple outflows in the high-mass cluster forming region, G25.82-0.17

Astrophysics of Galaxies 2020-07-01 v1 Solar and Stellar Astrophysics

Abstract

We present results of continuum and spectral line observations with ALMA and 22 GHz water (H2_2O) 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 CH3_3OH 81_{-1}-70_{0} E line, known to be a class I CH3_3OH maser at 229 GHz is also detected showing a mixture of thermal and maser emission. Moreover, the H2_2O masers are distributed in a region ~0.25" shifted from G25.82-W1. The CH3_3OH 224_{4}-215_{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.

Keywords

Cite

@article{arxiv.2005.05006,
  title  = {Multiple outflows in the high-mass cluster forming region, G25.82-0.17},
  author = {Jungha Kim and Mi Kyoung Kim and Tomoya Hirota and Kee-Tae Kim and Koichiro Sugiyama and Mareki Honma and Do-young Byun and Chungsik Oh and Kazuhito Motogi and Jihyun Kang and Jeongsook Kim and Tie Liu and Bo Hu and Ross A. Burns and James O. Chibueze and Naoko Matsumoto and Kazuyoshi Sunada},
  journal= {arXiv preprint arXiv:2005.05006},
  year   = {2020}
}

Comments

28 pages, 9 figures, accepted to ApJ