H I studies of the Sculptor group galaxies. V - NGC 253

Abstract

A study of the kinematics of the Sculptor group galaxy NGC 300 is presented. VLA* observations of the H I line show a dramatically warped H I disk just outside the optical disk. A two-component mass model, fitted to the data, gives a total mass of 2.4?1010 script M sign? at the last observed point of the rotation curve. This value implies a (script M sign/LB)global?11 script M sign?/L? for the galaxy which is compared with the total dynamical (script M sign/LB)dyn of the group. This comparison suggests that dark matter is probably more concentrated around the galaxies of the group than uniformly distributed in the intergalactic medium.