Hydroxyl lines towards Puppis A

The 1667-MHz ground-state hydroxyl (OH) line has been observed towards posi tions on Puppis A as well as in the immediate vicinity of this supernova re mnant (SNR). The spectra at two positions on Puppis A show absorption lines at velocities less than +7.6 km s(-1), and emission lines above this veloc ity. Analysis of all four 18 cm OH lines indicates that Puppis A must lie b etween the OH clouds seen in absorption and emission, giving it a v(lsr) of +7.6 km s(-1). This implies that the kinematic distance to Puppis A is 1.3 (-0.8)(+0.6)kpc. The OH clouds in front of Puppis A are slightly anomalousl y excited, as shown by analysis of the four 18 cm OH lines at the two obser ved positions on Puppis A. There is no evidence of any interaction of the S NR with the clouds in front of and behind it.