2012AJ....143...97A

We have mapped faint 1667 OH line emission (T_A~ 20-40 mK in our ~30' beam) along many lines of sight in the Galaxy covering an area of ~4°x4° in the general direction of l ~ 108°, b ~ 5°. The OH emission is widespread, similar in extent to the local H I (r ≲ 2 kpc) both in space and in velocity. The OH profile amplitudes show a good general correlation with those of H I in spectral channels of ~1 km/s; this relation is described by T_A(OH) ~1.50x10^–4 T_B (H I) for values of T_B(H I) ≲ 60-70 K. Beyond this the H I line appears to "saturate," and few values are recorded above ~90 K. However, the OH brightness continues to rise, by a further factor ~3. The OH velocity profiles show multiple features with widths typically 2-3 km/s, but less than 10% of these features are associated with CO(1-0) emission in existing surveys of the area smoothed to comparable resolution.