@misc{10481/84954,
year = {2023},
month = {8},
url = {https://hdl.handle.net/10481/84954},
abstract = {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.},
organization = {Anhui Province
	2022AH010013, 2022YFA1605300},
organization = {CAMS-CAS},
organization = {Proyecto
	A-FQM-510-UGR20},
organization = {Zhejiang Lab Open Research Project
	K2022PE0AB01},
organization = {Chinese Academy of Sciences South America Center for Astronomy
 11733006, 11803044, 12173045, CMS-CSST-2021-A05	CASSACA},
organization = {Consejería de Transformación Económica, Industria, Conocimiento y Universidades},
organization = {National Natural Science Foundation of China
 11873055, 11933003, 12273051, MCIN/AEI/10.13039/501100011033, P20_00334, PID2020-114414GB-100	NSFC},
organization = {Chinese Academy of Sciences
 CAS},
organization = {Knut och Alice Wallenbergs Stiftelse},
organization = {European Regional Development Fund
 	ERDF},
organization = {People's Government of Yunnan Province},
organization = {Junta de Andalucía},
organization = {National Key Research and Development Program of China
 2017YFA0402704, 2018YFE0202900	NKRDPC},
publisher = {Institute of Physics},
keywords = {Hickson compact group},
keywords = {Galaxy groups},
keywords = {H I line emission},
title = {Deep H i Mapping of Stephan’s Quintet and Its Neighborhood},
doi = {10.3847/1538-4357/ace03e},
author = {Cheng, Cheng and Lisenfeld, Ute},
}