The ALMA-ATOMS survey: A sample of weak hot core candidates identified through line stacking
Abstract
Hot cores represent critical astrophysical environments for high-mass star formation, distinguished by their rich spectra of organic molecular emission lines. We aim to utilize high-angular resolution molecular line data from 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. We propose to use spectral stacking and imaging techniques of complex organic molecules (COMs) in the ALMA-ATOMS survey, including line identification & weights, segmentation of line datacubes, resampling, stacking and normalization, moment 0 maps, and data analysis, to search for hot core candidates. We classify cores with dense emission of CH3OH and at least one molecule from the other six molecules as hot core candidates. 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 those 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. 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.
Cite
@article{arxiv.2504.06802,
title = {The ALMA-ATOMS survey: A sample of weak hot core candidates identified through line stacking},
author = {Zi-Yang Li and Xunchuan Liu and Tie Liu and Sheng-Li Qin and Paul F. Goldsmith and Pablo García and Yaping Peng and Li Chen and Yunfan Jiao and Zhiping Kou and Chuanshou Li and Jiahang Zou and Mengyao Tang and Shanghuo Li and Meizhu Liu and Guido Garay and Fengwei Xu and Wenyu Jiao and Qiu-Yi Luo and Suinan Zhang and Qi-Lao Gu and Xiaofeng Mai and Yan-Kun Zhang and Jixiang Weng and Chang Won Lee and Patricio Sanhueza and Sami Dib and Swagat R. Das and Xindi Tang and Leonardo Bronfman and Prasanta Gorai and Ken'ichi Tatematsu and Hong-Li Liu and Dongting Yang and Zhenying Zhang and Xianjin Shen},
journal= {arXiv preprint arXiv:2504.06802},
year = {2025}
}