The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). X. Hot Gas Reveals Deeply Embedded Star Formation
Massive infrared dark clouds (IRDCs) are considered to host the earliest stages of high-mass star formation. In particular, 70 μ m dark IRDCs are the colder and more quiescent clouds. At a scale of about 5000 au using formaldehyde (H _2 CO) emission, we investigate the kinetic temperature of dense c...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2024-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ad18c6 |
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| author | Natsuko Izumi Patricio Sanhueza Patrick M. Koch Xing Lu Shanghuo Li Giovanni Sabatini Fernando A. Olguin Qizhou Zhang Fumitaka Nakamura Ken’ichi Tatematsu Kaho Morii Takeshi Sakai Daniel Tafoya |
| author_facet | Natsuko Izumi Patricio Sanhueza Patrick M. Koch Xing Lu Shanghuo Li Giovanni Sabatini Fernando A. Olguin Qizhou Zhang Fumitaka Nakamura Ken’ichi Tatematsu Kaho Morii Takeshi Sakai Daniel Tafoya |
| author_sort | Natsuko Izumi |
| collection | DOAJ |
| description | Massive infrared dark clouds (IRDCs) are considered to host the earliest stages of high-mass star formation. In particular, 70 μ m dark IRDCs are the colder and more quiescent clouds. At a scale of about 5000 au using formaldehyde (H _2 CO) emission, we investigate the kinetic temperature of dense cores in 12 IRDCs obtained from the pilot Atacama Large Millimeter/submillimeter Array Survey of 70 μ m dark High-mass clumps in Early Stages (ASHES). Compared to the 1.3 mm dust continuum and other molecular lines, such as C ^18 O and deuterated species, we find that H _2 CO is mainly sensitive to low-velocity outflow components rather than to quiescent gas expected in the early phases of star formation. The kinetic temperatures of these components range from 26 to 300 K. The Mach number reaches about 15 with an average value of about 4, suggesting that the velocity distribution of gas traced by H _2 CO is significantly influenced by a supersonic nonthermal component. In addition, we detect warm line emission from HC _3 N and OCS in 14 protostellar cores, which requires high excitation temperatures ( E _u / k ∼ 100 K). These results show that some of the embedded cores in the ASHES fields are in an advanced evolutionary stage, previously unexpected for 70 μ m dark IRDCs. |
| first_indexed | 2024-04-25T01:32:31Z |
| format | Article |
| id | doaj.art-91dd913f772a44caa839b99d4705350b |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-04-25T01:32:31Z |
| publishDate | 2024-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-91dd913f772a44caa839b99d4705350b2024-03-08T11:22:54ZengIOP PublishingThe Astrophysical Journal1538-43572024-01-01963216310.3847/1538-4357/ad18c6The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). X. Hot Gas Reveals Deeply Embedded Star FormationNatsuko Izumi0https://orcid.org/0000-0003-1604-9127Patricio Sanhueza1https://orcid.org/0000-0002-7125-7685Patrick M. Koch2https://orcid.org/0000-0003-2777-5861Xing Lu3https://orcid.org/0000-0003-2619-9305Shanghuo Li4https://orcid.org/0000-0003-1275-5251Giovanni Sabatini5https://orcid.org/0000-0002-6428-9806Fernando A. Olguin6https://orcid.org/0000-0002-8250-6827Qizhou Zhang7https://orcid.org/0000-0003-2384-6589Fumitaka Nakamura8https://orcid.org/0000-0001-5431-2294Ken’ichi Tatematsu9https://orcid.org/0000-0002-8149-8546Kaho Morii10https://orcid.org/0000-0002-6752-6061Takeshi Sakai11https://orcid.org/0000-0003-4521-7492Daniel Tafoya12https://orcid.org/0000-0002-2149-2660Institute of Astronomy and Astrophysics , Academia Sinica, No. 1, Section 2, Roosevelt Road, Taipei 10617, TaiwanNational Astronomical Observatory of Japan, National Institutes of Natural Sciences , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Astronomical Science Program, The Graduate University for Advanced Studies , SOKENDAI, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, JapanInstitute of Astronomy and Astrophysics , Academia Sinica, No. 1, Section 2, Roosevelt Road, Taipei 10617, TaiwanShanghai Astronomical Observatory, Chinese Academy of Sciences , 80 Nandan Road, Shanghai 200030, People's Republic of ChinaMax Planck Institute for Astronomy , Konigstuhl 17, D-69117 Heidelberg, GermanyINAF , Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125, Firenze, ItalyInstitute of Astronomy, National Tsing Hua University , Hsinchu 30013, TaiwanCenter for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USANational Astronomical Observatory of Japan, National Institutes of Natural Sciences , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Astronomical Science Program, The Graduate University for Advanced Studies , SOKENDAI, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Department of Astronomy, Graduate School of Science, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanNational Astronomical Observatory of Japan, National Institutes of Natural Sciences , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Astronomical Science Program, The Graduate University for Advanced Studies , SOKENDAI, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, JapanNational Astronomical Observatory of Japan, National Institutes of Natural Sciences , 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan; Department of Astronomy, Graduate School of Science, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, JapanGraduate School of Informatics and Engineering, The University of Electro-Communications , Chofu, Tokyo 182-8585, JapanDepartment of Space, Earth and Environment, Chalmers University of Technology , Onsala Space Observatory, SE-439 92 Onsala, SwedenMassive infrared dark clouds (IRDCs) are considered to host the earliest stages of high-mass star formation. In particular, 70 μ m dark IRDCs are the colder and more quiescent clouds. At a scale of about 5000 au using formaldehyde (H _2 CO) emission, we investigate the kinetic temperature of dense cores in 12 IRDCs obtained from the pilot Atacama Large Millimeter/submillimeter Array Survey of 70 μ m dark High-mass clumps in Early Stages (ASHES). Compared to the 1.3 mm dust continuum and other molecular lines, such as C ^18 O and deuterated species, we find that H _2 CO is mainly sensitive to low-velocity outflow components rather than to quiescent gas expected in the early phases of star formation. The kinetic temperatures of these components range from 26 to 300 K. The Mach number reaches about 15 with an average value of about 4, suggesting that the velocity distribution of gas traced by H _2 CO is significantly influenced by a supersonic nonthermal component. In addition, we detect warm line emission from HC _3 N and OCS in 14 protostellar cores, which requires high excitation temperatures ( E _u / k ∼ 100 K). These results show that some of the embedded cores in the ASHES fields are in an advanced evolutionary stage, previously unexpected for 70 μ m dark IRDCs.https://doi.org/10.3847/1538-4357/ad18c6Infrared dark cloudsStar formationStar forming regionsMassive starsProtoclustersProtostars |
| spellingShingle | Natsuko Izumi Patricio Sanhueza Patrick M. Koch Xing Lu Shanghuo Li Giovanni Sabatini Fernando A. Olguin Qizhou Zhang Fumitaka Nakamura Ken’ichi Tatematsu Kaho Morii Takeshi Sakai Daniel Tafoya The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). X. Hot Gas Reveals Deeply Embedded Star Formation The Astrophysical Journal Infrared dark clouds Star formation Star forming regions Massive stars Protoclusters Protostars |
| title | The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). X. Hot Gas Reveals Deeply Embedded Star Formation |
| title_full | The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). X. Hot Gas Reveals Deeply Embedded Star Formation |
| title_fullStr | The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). X. Hot Gas Reveals Deeply Embedded Star Formation |
| title_full_unstemmed | The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). X. Hot Gas Reveals Deeply Embedded Star Formation |
| title_short | The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). X. Hot Gas Reveals Deeply Embedded Star Formation |
| title_sort | alma survey of 70 μm dark high mass clumps in early stages ashes x hot gas reveals deeply embedded star formation |
| topic | Infrared dark clouds Star formation Star forming regions Massive stars Protoclusters Protostars |
| url | https://doi.org/10.3847/1538-4357/ad18c6 |
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