Arecibo emission-absorption observations of Galactic OH

Observations of OH emission/absorption toward 19 low-Galactic-latitude background-continuum sources are reported. Data obtained at 1.665 and 1.667 GHz using the 12-m radio telescope at Arecibo Observatory during February-March 1984, are presented in extensive tables and graphs and characterized in detail, with reference to theoretical models. A total of 11 OH absorption features were detected toward nine of the sources, with an average of one feature of optical depth 0.02 or greater per 5 kpc of path length and an average column density of 1.6 x 10 to the 12th/sq cm (corrected to b = 90 deg).