2001ApJ...548L..65M

We present observations of C₂H₅OH toward molecular clouds in Sgr A and Sgr B2 and associated with thermal and nonthermal features in the Galactic center (GC). C₂H₅OH emission in Sgr A and Sgr B2 is widespread but not uniform. C₂H₅OH emission is much weaker, or it is not detected in some molecular clouds in both complexes, in particular those with radial velocities between 70 and 120 km.s^–1. While most of the clouds associated with the thermal features do not show C₂H₅OH emission, that associated with the nonthermal radio arc shows emission. The fractional abundance of C₂H₅OH in most of the clouds with radial velocities between 0 and 70 km.s^–1 in Sgr A and Sgr B2 is relatively high, of a few times 10^–8. The C₂H₅OH abundance decreases by more than a factor of 10 (≲10^–9) in the clouds associated with the thermal features. The large abundance of C₂H₅OH in the gas phase indicates that C₂H₅OH has formed in grains and released to gas phase by shocks in the last ∼10⁵ yr. The implications of this finding in the origin of the shocks in the GC is briefly discussed.