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| Materiálatiipa: | Preprint |
| Almmustuhtton: |
2024
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| Fáttát: | |
| Liŋkkat: | https://arxiv.org/abs/2410.17455 |
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| _version_ | 1866917813023670272 |
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| author | Zhang, Siju Liu, Tie Wang, Ke Zavagno, Annie Garay, Guido Liu, Hongli Xu, Fengwei Liu, Xunchuan Sanhueza, Patricio Soam, Archana Zhou, Jian-wen Li, Shanghuo Goldsmith, Paul F. Zhang, Yong Chibueze, James O. Lee, Chang Won Hwang, Jihye Bronfman, Leonardo Dewangan, Lokesh K. |
| author_facet | Zhang, Siju Liu, Tie Wang, Ke Zavagno, Annie Garay, Guido Liu, Hongli Xu, Fengwei Liu, Xunchuan Sanhueza, Patricio Soam, Archana Zhou, Jian-wen Li, Shanghuo Goldsmith, Paul F. Zhang, Yong Chibueze, James O. Lee, Chang Won Hwang, Jihye Bronfman, Leonardo Dewangan, Lokesh K. |
| contents | Fragmentation and evolution for the molecular shells of the compact HII regions are less explored compared to their evolved counterparts. We map nine compact HII 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 H13CO+ are embedded in these molecular shells. These gas fragments, strongly affected by the HII 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 HII 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 HII regions, by comparing the expected time scale of shell fragmentation with the age of HII 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. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2410_17455 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | 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 HII regions Zhang, Siju Liu, Tie Wang, Ke Zavagno, Annie Garay, Guido Liu, Hongli Xu, Fengwei Liu, Xunchuan Sanhueza, Patricio Soam, Archana Zhou, Jian-wen Li, Shanghuo Goldsmith, Paul F. Zhang, Yong Chibueze, James O. Lee, Chang Won Hwang, Jihye Bronfman, Leonardo Dewangan, Lokesh K. Astrophysics of Galaxies Solar and Stellar Astrophysics Fragmentation and evolution for the molecular shells of the compact HII regions are less explored compared to their evolved counterparts. We map nine compact HII 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 H13CO+ are embedded in these molecular shells. These gas fragments, strongly affected by the HII 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 HII 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 HII regions, by comparing the expected time scale of shell fragmentation with the age of HII 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. |
| title | 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 HII regions |
| topic | Astrophysics of Galaxies Solar and Stellar Astrophysics |
| url | https://arxiv.org/abs/2410.17455 |