# HI Galaxies

Using a 19 beam L-band receiver to map the FAST sky in commensal observing mode to reach an rms level of 0.7 mJy/beam at 0.1 MHz (20 km/s) resolution. The survey expect to detect more than several hundred thousands HI galaxies (Duffy et al. 2008, 2012) with MHI< 1011M_sun out to z ~ 0.3 in a range of environments.

Major science goals include:

• Study the HI Large scale structure and test the ΛCDM model
• Obtain the HI Mass Function in different cosmic environments
• Mapping the local Voids
• Mapping the Milky Way (HVCs, Magellanic Stream … )
• Understand the role of neutral hydrogen in galaxy formation and evolution
• Search for High z OH megamaser