1995A&AS..114..147B

Six southern spiral galaxies, with diameters between 5' and 8', were mapped with the SEST in the ¹²CO(1-0) line. CO emission was detected in five of the galaxies. The 43" beam of the SEST, at 115GHz, was small enough for determining the general distribution of the gas, which is centrally peaked in all the cases, and the velocity field from which we could derive the major axis position angle and the rotation curve. The latter is, in general, very steep at the centre and quite flat after the turn-over point. It was used to estimate the total mass of the galaxy up to the farthest measured point. The gas mass was estimated from the CO and H I global velocity profiles. On three of the galaxies the ¹²CO(2-1) and ¹³CO(1-0) lines were also observed on their centres, the first one on a 10" grid, covering a region of 20"x20", and the second on one point towards the centre. The average ratio between the intensities of the ¹²CO(2-1) and ¹²CO(1-0) spectra is 1.3 in the three cases. The detections of the ¹³CO(1-0) were only marginal. A good correlation has been found between the CO and the continuum emission at 843MHz.