The ALMA-ATOMS survey: A sample of weak hot core candidates identified through line stacking
Year: 2025
Type: article
Abstract: Context. Hot cores represent critical astrophysical environments for high-mass star formation, distinguished by their rich spectra of organic molecular emission lines. Nevertheless, comprehensive statistical analyses of extensive hot core samples remain relatively scarce in current astronomical research. Aims. We aim to utilize high-angular-resolution molecular line data from the Atacama Large Millimeter and Submillimeter Array (ALMA) to identify hot cores, with a particular focus on weak-emission candidates, and to provide one of the largest samples of hot core candidates to date. Methods. We propose to use spectral stacking and imaging techniques of complex organic molecules (COMs) in the ALMA-ATOMS survey, including line identification and weights, segmentation of line datacubes, resampling, stacking and normalization, moment 0 maps, and data analysis, to search for hot core candidates. The molecules involved include CH3OH, CH3OCHO, C2H5CN, C2H5OH, CH3OCH3, CH3COCH3, and CH3CHO. We classify cores with dense emission of CH3OH and at least one molecule from the other six molecules as hot core candidates. Results. In addition to the existing sample of 60 strong hot cores from the ALMA-ATOMS survey, we have detected 40 new weak candidates through stacking. All hot core candidates display compact emission from at least one of the other six COM species. For the strong sample, the stacking method provides molecular column density estimates that are consistent with previous fitting results. For the newly identified weak candidates, all species except CH3CHO show compact emission in the stacked image, which cannot be fully resolved spatially. These weak candidates exhibit column densities of COMs that are approximately one order of magnitude lower than the ones of the strong sample. The entire hot core sample, including the weak candidates, reveals tight correlations between the compact emission of CH3OH and other COM species, suggesting they may share a similar chemical environment for COMs, with CH3OH potentially acting as a precursor for other COMs. Among the 100 hot cores in total, 43 exhibit extended CH3CHO emission spatially correlated with SiO and H13CO+, suggesting that CH3CHO may form in widely distributed shock regions. Conclusions. The molecular line stacking technique is used to identify hot core candidates in this work, leading to the identification of 40 new hot core candidates. Compared to spectral line fitting methods, it is faster and more convenient, and enables weaker hot cores to be detected with greater sensitivity.
Authors: Zi-Yang Li, Xunchuan Liu, Tie Liu, Sheng-Li Qin, Paul F. Goldsmith, Pablo García, Yaping Peng, Li Chen, Yunfan Jiao, Zhiping Kou, Chuanshou Li, Jiahang Zou, Mengyao Tang, Shanghuo Li, Meizhu Liu, Guido Garay, Fengwei Xu, Wenyu Jiao, Qiu-Yi Luo, Suinan Zhang, Qi-Lao Gu, Xiaofeng Mai, Yan-Kun Zhang, Jixiang Weng, Chang Won Lee, Patricio Sanhueza, Sami Dib, Swagat R. Das, Xindi Tang, Leonardo Bronfman, Prasanta Gorai, Ken’ichi Tatematsu, Hong-Li Liu, Dongting Yang, Zhenying Zhang, Xianjin Shen
Institutions: Yunnan University, Shanghai Astronomical Observatory, Jet Propulsion Laboratory, Chinese Academy of Sciences, Universidad Católica del Norte, National Astronomical Observatories, Kunming University of Science and Technology, University of Chinese Academy of Sciences, Chuxiong Normal University, Nanjing University, Guangzhou University, University of Chile, University of Cologne, Peking University, Korea Astronomy and Space Science Institute, Korea University of Science and Technology, Max Planck Institute for Astronomy, Xinjiang Astronomical Observatory, University of Oslo, National Institutes of Natural Sciences, National Astronomical Observatory of Japan
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Aeronautics and Space Administration, California Institute of Technology, National Natural Science Foundation of China, Chinese Academy of Sciences, Korea Astronomy and Space Science Institute, Ministry of Education, Science and Technology, Ministry of Science and ICT, South Korea, Agencia Nacional de Investigación y Desarrollo, Jet Propulsion Laboratory, Japan Society for the Promotion of Science
OpenAlex ID: W6884497603
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