Chuan-Peng Zhang
National Astronomical Observatories, Chinese Academy of Sciences
About Me
| Social Media | ADS Library · MPIA · GitHub · Flickr |
| cpzhang@nao.cas.cn | |
| Address | Beijing, China |
| Phone | 010-64867671 |
| Office | A232 @ NAOC |
Current Work
The FAST All Sky H I Survey (FASHI) conducted with the Five-hundred-meter Aperture Spherical radio Telescope (FAST) has mapped ∼19 500 deg2 of the sky north of DEC = −14°, detecting 156 411 extragalactic H I sources at z < 0.09 with a median sensitivity of 0.57 mJy beam−1 at a velocity resolution of 6.4 km 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 H I mass function (HIMF) using a completeness‑corrected sample of over 109 000 sources. The HIMF is robustly constrained down to MHI ∼ 106.2 M⊙. When systematic uncertainties are included, the HIMF is well described by a single-Schechter function with a characteristic mass log(Ms/h70−2 M⊙) = 9.89 ± 0.02, low-mass end slope α = −1.31 ± 0.02 and amplitude φs = (6.38 ± 0.49) × 10−3 h703 Mpc−3 dex−1. The derived cosmic H I density is ΩHI = (4.71 ± 0.03stat ± 0.40sys) × 10−4 h70−1.
FASHI provides the most extensive and sensitive H I catalog to date, establishing an important benchmark for studies of gas accretion, galaxy evolution, and large-scale structure in the local universe.