FEASTS
FEASTS (FAST Extended-Atlas-of-Selected-Targets Survey) targets HI-richest galaxies in the Local Volume. It takes advantage of the high sensitivity and low side-lobe of FAST (Five-hundred-meter Aperture Spherical radio Telescope) in China, and aims to map the extended and low-surface density HI, which is typically missed in interferometric observations.
The sample is an almost HI-flux-complete sample of 55 galaxies. These galaxies all have extended HI disks that can be relatively well resolved by FAST's beam of ~3 arcmin (Wang et al. 2025). The observation uses the fast-OTF mode with speed equivalent to drift, and covers the same field multiple (>=6) times to reduce the contamination from RFI and other artifacts. The moment-0 images reach a typical 3-sigma depth of 5e17 cm^-2 (assuming 20 km/s line width). All the data of the observed 55 galaxies has been released on the Data Release Page. If you have any questions, please email Jing Wang.
FEASTS studies the evolution of Local Volume galaxies with grand HI disks. The major science goals include but are not limited to the following:
- A uniform set of HI images taken with FAST for HI-richest galaxies in the Local Volume.
- First characterization of diffuse HI and HI clouds in the IGM/CGM of galaxies.
- A statistical measure of HI radial profiles in/above the CGM-disk interface.
- Modification to the star formation law and star formation theories.
- A new census of HI-rich dwarf satellites.
- Environmental effects that accrete or deplete gas in galaxies.
History of the program as a function of look-back time:
Aug 2023-Aug 2024, observations 2024.
- The team mapped another ~15 galaxies.
Aug 2022-Aug 2023, observations 2023.
- The team mapped 15-20 well-resolved nearby galaxies, which have characteristic RHI>3FWHM the PSF of FAST, or have signature of extended but unconfirmed HI in the literature. All these galaxies have existing interferometric HI images.
Aug 2021-Aug 2022, observations 2022.
- The team has mapped 20 well-resolved nearby galaxies, which have characteristic RHI>3FWHM the PSF of FAST, or have signature of extended but unconfirmed HI in the literature. All these galaxies have existing interferometric HI images. The observations reached a planned 5-sigma limit N_HI~ 10^17.9 cm^2 (20 km/s line widths assumed).An atlas of 10 galaxies observed is shown at the top of this page.
- Below, we highlight the FAST(FEASTS)+WSRT(HALOGAS) combined HI image of the NGC 4631 group, and a video comparing the 3d views of the two datasets. A detailed study of this system is present in (Wang et al. 2023), and summarized here.
Active working groups
(Names of captains highlighted)
TWG1: FAST HI data observation & processing
Qifeng Huang, Yingjie Jing, Ziming Liu, Lister Staveley-Smith, Jie Wang, Jing Wang, Dong Yang
TWG2: interferometric HI data, FAST+interferometric data combination
Xinkai Chen, George Heald, Kelley Hess,Xuchen Lin, Lister Staveley-Smith, Ran Wang, Jing Wang, Fabian Walter
TWG3: multi-wavelength data
Cheng Li, Zezhong Liang, Li Shao, Ran Wang, Zhimin Zhou, Hu Zou
Team of Organization
Jing Wang (PI)