Infall Motions in the Hot Core Associated with the Hypercompact H ii Region G345.0061+01.794 B
Komesh T. Garay G. Henkel C. Omar A. Estalella R. Assembay Z. Li D. Guzmán A. Esimbek J. Huang J. He Y. Alimgazinova N. Kyzgarina M. Bekdaulet S. Zhumabay N. Manapbayeva A.
1 May 2024Institute of Physics
Astrophysical Journal
2024#967Issue 1
We report high angular resolution observations, made with the Atacama Large Millimeter Array in band 6, of high excitation molecular lines of CH 3 CN and SO2 and of the H29α radio recombination line toward the G345.0061+01.794 B HC H ii region in order to investigate the physical and kinematical characteristics of its surroundings. Emission was detected in all observed components of the J = 14 →13 rotational ladder of CH 3 CN and in the 304,26-303,27, and 324,28-323,29 lines of SO2. The peak of the velocity-integrated molecular emission is located ∼0.″4 northwest of the peak of the continuum emission. The first-order moment images and channel maps show a velocity gradient of 1.1 km s−1 arcsec−1 across the source and a distinctive spot of blueshifted emission toward the peak of the zero-order moment. The rotational temperature is found to decrease from 252±24 K at the peak position to 166±16 K at its edge, indicating that our molecular observations are probing a hot molecular core that is internally excited. The emission in the H29α line arises from a region of 0.″65 in size, where its peak coincides with that of the dust continuum. We model the kinematical characteristics of the “central blue spot” feature as due to infalling motions, suggesting a central mass of 172.8±8.8 M ⊙. Our observations indicate that this HC H ii region is surrounded by a compact structure of hot molecular gas, which is rotating and infalling toward a central mass, that is most likely confining the ionized region. The observed scenario is reminiscent of a “butterfly pattern” with an approximately edge-on torus and ionized gas roughly parallel to its rotation axis.
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Energetic Cosmos Laboratory, Nazarbayev University, Astana, 010000, Kazakhstan
Institute of Experimental and Theoretical Physics, Al-Farabi Kazakh National University, Almaty, 050040, Kazakhstan
Departamento de Astronomia, Universidad de Chile, Camino el Observatorio 1515 Las Condes, Santiago, Chile
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, Bonn, 53121, Germany
Xinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi, 830011, China
Astronomy Department, King Abdulaziz University, PO Box 80203, Jeddah, 21589, Saudi Arabia
Faculty of Physics and Technology, Al-Farabi Kazakh National University, Almaty, 050040, Kazakhstan
Departament de Física Quàntica i Astrofísica, Institut de Ciències del Cosmos, Universitat de Barcelona, IEEC-UB, Martí i Franquès 1, Barcelona, 08028, Spain
National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo, 181-8588, Japan
Chinese Academy of Sciences, South America Center for Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing, 100101, China
Heriot-Watt International Faculty, Zhubanov University, 263 Zhubanov Brothers Street, Aktobe, 030000, Kazakhstan
Department of Computation and Data Science, Astana IT University, 55/11 Mangilik El Avenue, Astana, 010000, Kazakhstan
Fesenkov Astrophysical Institute, 23 Observatory Street, Almaty, 050020, Kazakhstan
Institute of Mathematics, Physics and Informatics, Abai Kazakh National Pedagogical University, Almaty, 050010, Kazakhstan
Energetic Cosmos Laboratory
Institute of Experimental and Theoretical Physics
Departamento de Astronomia
Max-Planck-Institut für Radioastronomie
Xinjiang Astronomical Observatory
Astronomy Department
Faculty of Physics and Technology
Departament de Física Quàntica i Astrofísica
National Astronomical Observatory of Japan
Chinese Academy of Sciences
Heriot-Watt International Faculty
Department of Computation and Data Science
Fesenkov Astrophysical Institute
Institute of Mathematics
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