A study of the interstellar medium in line to NGC 5128 from high resolution observations of the supernova 1986G

Interstellar absorption on the line of sight to SN 1986G in NGC 5128 is investigated on the basis of high-resolution high-S/N observations obtained with the Caspec echelle spectrograph at the f/8 Cassegrain focus of the 3.6-m telescope at ESO on May 7-11, 1986. The data are presented in extensive tables and graphs and characterized in detail. Evidence is found for a warped disk or ring of cool gas, spread over a velocity range of about 178 km/sec and with 12 or more distinct clouds absorbing Ca II and Na I; three of the seven components have Ca(+)/Na(0) column-density ratios less than 1. Also detected are two absorption components with vH of 236 and 257 km/sec (possibly associated with high-velocity H I clouds), diffuse interstellar bands at both Galactic and NGC 5128 velocities, and optical CH and CH(+) absorption lines.