Infall Motions in the Hot Core Associated with Hypercompact HII Region G345.0061+01.794 B
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| Autores principales: | , , , , , , , , , , , , , , , |
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2023
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| author | Komesh, Toktarkhan Garay, Guido Henkel, Christian Omar, Aruzhan Estalella, Robert Assembay, Zhandos Li, Dalei Guzmán, Andrés Esimbek, Jarken Huang, Jiasheng He, Yuxin Alimgazinova, Nazgul Kyzgarina, Meiramgul Bekdaulet, Shukirgaliyev Zhumabay, Nurman Manapbayeva, Arailym |
| author_facet | Komesh, Toktarkhan Garay, Guido Henkel, Christian Omar, Aruzhan Estalella, Robert Assembay, Zhandos Li, Dalei Guzmán, Andrés Esimbek, Jarken Huang, Jiasheng He, Yuxin Alimgazinova, Nazgul Kyzgarina, Meiramgul Bekdaulet, Shukirgaliyev Zhumabay, Nurman Manapbayeva, Arailym |
| contents | We report high angular resolution observations, made with the Atacama Large Millimeter Array in band 6, of high excitation molecular lines of $\rm CH_3CN$ and $\rm SO_2$ and of the H29$α$ radio recombination line towards 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$\rightarrow$13 rotational ladder of $\rm CH_3CN$ and in the $30_{4,26}-30_{3,27}$ and $32_{4,28}-32_{3,29}$ lines of $\rm SO_2$. The peak of the velocity integrated molecular emission is located $\sim$0$\,.\!\!^{\prime\prime}$4 northwest of the peak of the continuum emission. The first-order moment images and channel maps show a velocity gradient, of 1.1 km s$^{-1}$ arcsec$^{-1}$, across the source, and a distinctive spot of blueshifted emission towards the peak of the zero-order moment. The rotational temperature is found to decrease from 252$\pm24$ Kelvin at the peak position to 166$\pm16$ Kelvin at its edge, indicating that our molecular observations are probing a hot molecular core that is internally excited. The emission in the H29$α$ line arises from a region of 0$\,.\!\!^{\prime\prime}$65 in size, where its peak coincides with that of the dust continuum. We model the kinematical characteristics of the "central blue spot" feature as due to infalling motions, suggesting a central mass of 172.8$\pm8.8 M_{\odot}$. 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. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2307_07459 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Infall Motions in the Hot Core Associated with Hypercompact HII Region G345.0061+01.794 B Komesh, Toktarkhan Garay, Guido Henkel, Christian Omar, Aruzhan Estalella, Robert Assembay, Zhandos Li, Dalei Guzmán, Andrés Esimbek, Jarken Huang, Jiasheng He, Yuxin Alimgazinova, Nazgul Kyzgarina, Meiramgul Bekdaulet, Shukirgaliyev Zhumabay, Nurman Manapbayeva, Arailym Astrophysics of Galaxies We report high angular resolution observations, made with the Atacama Large Millimeter Array in band 6, of high excitation molecular lines of $\rm CH_3CN$ and $\rm SO_2$ and of the H29$α$ radio recombination line towards 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$\rightarrow$13 rotational ladder of $\rm CH_3CN$ and in the $30_{4,26}-30_{3,27}$ and $32_{4,28}-32_{3,29}$ lines of $\rm SO_2$. The peak of the velocity integrated molecular emission is located $\sim$0$\,.\!\!^{\prime\prime}$4 northwest of the peak of the continuum emission. The first-order moment images and channel maps show a velocity gradient, of 1.1 km s$^{-1}$ arcsec$^{-1}$, across the source, and a distinctive spot of blueshifted emission towards the peak of the zero-order moment. The rotational temperature is found to decrease from 252$\pm24$ Kelvin at the peak position to 166$\pm16$ Kelvin at its edge, indicating that our molecular observations are probing a hot molecular core that is internally excited. The emission in the H29$α$ line arises from a region of 0$\,.\!\!^{\prime\prime}$65 in size, where its peak coincides with that of the dust continuum. We model the kinematical characteristics of the "central blue spot" feature as due to infalling motions, suggesting a central mass of 172.8$\pm8.8 M_{\odot}$. 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. |
| title | Infall Motions in the Hot Core Associated with Hypercompact HII Region G345.0061+01.794 B |
| topic | Astrophysics of Galaxies |
| url | https://arxiv.org/abs/2307.07459 |