| Abstract | The molecular gas distribution in the nuclear regions of galaxies can be classified into three types: a core (C) type with a high-density peak toward the nucleus; a compact-ring (CR) type with ring radius of ~ 200 pc; and a broad-ring (BR) type with ring radius of 750 pc. We discuss the possibility of using the ring radius as a cosmic distance indicator for galaxies up to about 100 Mpc. We stress that this geometrical method is independent of such correction factors as extinction and reddening. |
