| Abstract | Optical and 21-cm observations have been made of the small low-luminosity Sb III galaxy NGC 3067. Beyond the nuclear region, rotational velocities rise slowly to 151 km/sec at R = 7.3 kpc, near the limit of the optical disk. The velocity gradient is 5.2 km/sec per kpc. The absorption previously detected along the line of sight to the quasar 3C 232 is located near the minor axis of NGC 3067 at a projected distance of almost two galactic radii. If the absorption arises from gas in circular orbit in the plane of NGC 3067, geometrical considerations require that the rotation velocities continue to rise beyond the optical image, increasing to a velocity near 340 km/sec at R = 40 kpc. Such a velocity implies that 94% of the mass is located beyond the optical image; this mass has a mass/B luminosity ratio greater than 100. Observations at 21 cm at Arecibo have not detected hydrogen clouds at this radial distance, but place an upper limit of 10 to the 7th solar masses for the mass of a single cloud. |
