Deep H i Mapping of Stephan’s Quintet and Its Neighborhood Cheng, Cheng Lisenfeld, Ute Hickson compact group Galaxy groups H I line emission We thank the referee for careful reading and constructive suggestions. This work is supported by the National Key R&D Programme of China No. 2017YFA0402704 and National Natural Science Foundation of China (NSFC) No. 11873055 and sponsored (in part) by the Chinese Academy of Sciences (CAS) through a grant to the CAS South America Center for Astronomy. C.K.X. acknowledges NSFC grant No. 11733006. C.C. acknowledges NSFC grant No. 11803044 and 12173045. We acknowledge the science research grants from the China Manned Space Project with No. CMS-CSST-2021-A05. N.-Y.T. is sponsored by Zhejiang Lab Open Research Project (No. K2022PE0AB01), Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CAS, National key R&D program of China under grant No. 2018YFE0202900 and the University Annual Scientific Research Plan of Anhui Province (No. 2022AH010013). Y.S.D. acknowledges support from the National Key R&D Program of China for grant No. 2022YFA1605300 and the National Nature Science Foundation of China (NSFC) grants No. 12273051 and 11933003; J.-S.H. acknowledges NSFC grant No. 11933003. U.L. acknowledges support from project PID2020-114414GB-100, financed by MCIN/AEI/10.13039/501100011033, from project P20_00334 financed by the Junta de Andalucía and from FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades/Proyecto A-FQM-510-UGR20. F.R. acknowledges support from the Knut and Alice Wallenberg Foundation. This work made use of data from FAST, a Chinese national mega-science facility built and operated by the National Astronomical Observatories, CAS. We thank P. Jiang, L. Hou, C. Sun, and other FAST operation team members for support in the observations and data reduction, and Y. Huang and K.-X. Lu for helping with the optical spectroscopic observations. C.C. appreciates helpful comments about the usage of matplotlib from Dr. Wenda Zhang. The support of the staff of the Lijiang 2.4 m telescope is acknowledged. Funding for the Lijiang 2.4 m telescope has been provided by the CAS and the People's Government of Yunnan Province. This research has made use of the NASA/IPAC Extragalactic Database, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. We carried out deep mapping observations of the atomic hydrogen (H i) 21 cm line emission in a field centered on the famous galaxy group Stephan's Quintet (SQ), using the Five-hundred-meter Aperture Spherical Telescope (FAST) equipped with a 19-beam receiver. The final data cube reaches an H i column density sensitivity of 5σ = 2.1 × 1017 cm-2 per 20 km s-1 channel with an angular resolution of 4.′0. The discovery of a large diffuse feature of the H i emission in the outskirts of the intragroup medium of SQ was reported in a previous paper (Xu et al.). Here we present a new study of the total H i emission of SQ and the detection of several neighboring galaxies, exploiting the high sensitivity and the large sky coverage of the FAST observations. A total H i mass of M H I = 3.48 ± 0.35 × 1010 M ☉ is found for SQ, which is significantly higher than previous measurements in the literature. This indicates that, contrary to earlier claims, SQ is not H i deficient. The excessive H i gas is mainly found in the velocity ranges of 6200-6400 km s-1 and 6800-7000 km s-1, which were undetected in previous observations that are less sensitive than ours. Our results suggest that the "missing H i"in compact groups may be hidden in the low-density diffuse neutral gas instead of in the ionized gas. 2023-10-11T12:25:05Z 2023-10-11T12:25:05Z 2023-08-23 info:eu-repo/semantics/article Cheng Cheng et al. 2023. Deep H i Mapping of Stephan’s Quintet and Its Neighborhood. ApJ 954 74. [https://doi.org/10.3847/1538-4357/ace03e] https://hdl.handle.net/10481/84954 10.3847/1538-4357/ace03e eng http://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess Atribución 4.0 Internacional Institute of Physics