Deep HI Disk Radial Profiles and the R001 Size-Mass Relation in Galaxies
Using total-power FAST 21-cm imaging that reaches the 0.01 solar-mass-per-square-parsec level, defines a new galaxy-disk radius R001 at that iso-density contour and shows the outer HI radial profile is self-similar when normalized by R001, giving a very tight R001 versus HI-mass size-mass relation. The R001/R1 ratio correlates with a galaxy's HI-to-stellar-mass ratio and specific star-formation rate but not with stellar mass, HI mass or dark-matter mass, implying self-similar outer-disk gas transport absent major tidal interactions.
FEASTS: Radial Distribution of HI Surface Densities down to 0.01 Msun/pc2 of 35 Nearby Galaxies
Maps the neutral atomic hydrogen (HI) disks of 35 nearby galaxies with the FAST radio telescope in the FEASTS survey, reaching the very faint 0.01 solar-mass-per-square-parsec surface-density level -…