2026-09-10 中国科学院（CAS）
＜関連情報＞
- https://english.cas.cn/newsroom/cas-in-media/202609/t20260910_1195130.shtml
- https://link.springer.com/article/10.1007/s11433-026-3072-1
FAST全天H IサーベイDR2：FASHIカタログとH I質量関数 The FAST all sky Hi survey DR2: The FASHI catalog and the Hi mass function
Chuan-Peng Zhang,Ming Zhu,Peng Jiang,Hong Guo,Jin-Long Xu,Xiao-Lan Liu,Nai-Ping Yu,Cheng Cheng,Jing Wang,Jie Wang & FAST Collaboration
Science China Physics, Mechanics & Astronomy Published:08 September 2026
DOI:https://doi.org/10.1007/s11433-026-3072-1
Abstract
The FAST All Sky Hi Survey (FASHI) conducted with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) has mapped ∼19500 deg2 of the sky north of DEC = −14°, detecting 156 411 extragalactic Hi sources at z < 0.09 with a median sensitivity of 0.57 mJy beam−1 at a velocity resolution of 6.4km s−1. The survey achieves unprecedented depth and area coverage, significantly improving upon previous single-dish surveys. Through a detailed completeness analysis that accounts for the survey’s non-uniform sensitivity and line-width dependence, we construct a robust Hi mass function (HIMF) using a completeness-corrected sample of over 109000 sources. The HIMF is robustly constrained down to MHI ∼ 106.2M⊙. When systematic uncertainties are included, the HIMF is well described by a single-Schechter function with a characteristic mass log(Ms/h−270M⊙) = 9.89 ± 0.02, low-mass end slope α = −1.31 ± 0.02 and amplitude ϕs = (6.38 ± 0.49) × 10−3h370 Mpc−3 dex−1. The derived cosmic Hi density is ΩHI = (4.71 ± 0.03stat ± 0.40sys) × 10−4h−170. FASHI provides the most extensive and sensitive Hi catalog to date, establishing an important benchmark for studies of gas accretion, galaxy evolution, and large-scale structure in the local universe.
