Far-Infrared OH Fluorescent Emission in Sagittarius B2

Abstract

We present Infrared Space Observatory (ISO) observations of 16OH and 18OH toward Sgr B2 with a spectral resolution of ~35 km s-1. The OH J=5/2-->3/2 and J=3/2-->1/2 rotational lines of the 2Π1/2 ladder are seen in emission, while the cross-ladder transitions (from the 2Π3/2 J=3/2 to the J=1/2, 3/2, and 5/2 levels of the 2Π1/2 ladder) and the 2Π3/2 J=5/2