ATOMS: ALMA three-millimeter observations of massive star-forming regions – XVIII. On the origin and evolution of dense gas fragments in molecular shells of compact H <scp>ii</scp> regions

ABSTRACT Fragmentation and evolution for the molecular shells of the compact H ii regions are less explored compared to their evolved counterparts. We map nine compact H ii regions with a typical diameter of 0.4 pc that are surrounded by molecular shells traced by CCH. Several to a dozen dense gas fragments probed by H$^{13}$CO$^+$ are embedded in these molecular shells. These gas fragments, strongly affected by the H ii region, have a higher surface density, mass, and turbulence than those outside the shells but within the same pc-scale natal clump. These features suggest that the shells swept up by the early H ii regions can enhance the formation of massive dense structures that may host the birth of higher mass stars. We examine the formation of fragments and find that fragmentation of the swept-up shell is unlikely to occur in these early H ii regions, by comparing the expected time scale of shell fragmentation with the age of H ii region. We propose that the appearance of gas fragments in these shells is probably the result of sweeping up pre-existing fragments into the molecular shell that has not yet fragmented. Taken together, this work provides a basis for understanding the interplay of star-forming sites with an intricate environment containing ionization feedback such as those observed in starburst regions.

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Publication Details

Journal
Monthly Notices of the Royal Astronomical Society
Published
2024-10-23
DOI
https://doi.org/10.1093/mnras/stae2415
Citations
5
Primary Topic
Astrophysics and Star Formation Studies
Type
article
Field-Weighted Citation Impact
1.66

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article

ATOMS: ALMA three-millimeter observations of massive star-forming regions – XVIII. On the origin and evolution of dense gas fragments in molecular shells of compact H ii regions

Tie Liu, Jihye Hwang, Patricio Sanhueza, Xunchuan Liu et al.
5 citations
Monthly Notices of the Royal Astronomical Society
Astrophysics and Star Formation Studies
1.66
article

ATOMS: ALMA three-millimeter observations of massive star-forming regions – XVIII. On the origin and evolution of dense gas fragments in molecular shells of compact H ii regions

Tie Liu, Jihye Hwang, Patricio Sanhueza, Xunchuan Liu, Shanghuo Li, Fengwei Xu, L. K. Dewangan, Ke Wang, Siju Zhang, Chang Won Lee, P. F. Goldsmith, Yong Zhang, L. Bronfman, A. Zavagno, James O. Chibueze, Archana Soam, Guido Garay, Hongli Liu, Jianwen Zhou
article en
5 citations

Abstract

ABSTRACT Fragmentation and evolution for the molecular shells of the compact H ii regions are less explored compared to their evolved counterparts. We map nine compact H ii regions with a typical diameter of 0.4 pc that are surrounded by molecular shells traced by CCH. Several to a dozen dense gas fragments probed by H$^{13}$CO$^+$ are embedded in these molecular shells. These gas fragments, strongly affected by the H ii region, have a higher surface density, mass, and turbulence than those outside the shells but within the same pc-scale natal clump. These features suggest that the shells swept up by the early H ii regions can enhance the formation of massive dense structures that may host the birth of higher mass stars. We examine the formation of fragments and find that fragmentation of the swept-up shell is unlikely to occur in these early H ii regions, by comparing the expected time scale of shell fragmentation with the age of H ii region. We propose that the appearance of gas fragments in these shells is probably the result of sweeping up pre-existing fragments into the molecular shell that has not yet fragmented. Taken together, this work provides a basis for understanding the interplay of star-forming sites with an intricate environment containing ionization feedback such as those observed in starburst regions.

Monthly Notices of the Royal Astronomical SocietyVol. 535(2)
University of Nigeria (NG), Physical Research Laboratory (IN), Jet Propulsion Laboratory (US), Pioneer (United States) (US), Indian Institute of Astrophysics (IN), Sun Yat-sen University (CN), University of South Africa (ZA), Institut Universitaire de France (FR), Yunnan University (CN), Chinese Academy of Sciences (CN), National Institutes of Natural Sciences (JP), The Graduate University for Advanced Studies, SOKENDAI (JP), Peking University (CN), Aix-Marseille Université (FR), Shanghai Astronomical Observatory (CN), Korea Astronomy and Space Science Institute (KR), Galaxies, Etoiles, Physique et Instrumentation (FR), Kavli Institute for Theoretical Sciences (CN), Max Planck Institute for Astronomy (DE), Université Bourgogne Franche-Comté (FR), Max Planck Institute for Radio Astronomy (DE), National Astronomical Observatory of Japan (JP), National Astronomical Observatories (CN), University of Chile (CL), Korea University of Science and Technology (KR)
National Science Foundation, National Aeronautics and Space Administration, U.S. Nuclear Regulatory Commission, California Institute of Technology, Ministry of Science and Technology, Neurosciences Research Foundation, Chinese Academy of Sciences South America Center for Astronomy, National Natural Science Foundation of China, Chinese Academy of Sciences, Alberta Livestock and Meat Agency, Korea Astronomy and Space Science Institute, Ministry of Education, Science and Technology, Institut Universitaire de France, National Astronomical Observatory of Japan, Ministry of Science and ICT, South Korea, Agencia Nacional de Investigación y Desarrollo, Jet Propulsion Laboratory, Japan Society for the Promotion of Science, National Institutes of Natural Sciences, National Key Research and Development Program of China, National Astronomical Observatories, Chinese Academy of Sciences
Openalex Percentile: Top 16%
Astrophysics and Star Formation Studies
1.66
DOIOpen Access PDFOpenAlex
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