2019ApJ...887...79H

G23.33-0.30 is a 600 M_☉ infrared dark molecular filament that exhibits large NH₃ velocity dispersions (σ ∼ 8 km s^–1) and bright, narrow NH₃(3, 3) line emission. We have probed G23.33-0.30 at the < 0.1 pc scale and confirmed that the narrow NH₃(3, 3) line is emitted by four rare NH₃(3, 3) masers, which are excited by a large-scale shock impacting the filament. G23.33-0.30 also displays a velocity gradient along its length, a velocity discontinuity across its width, shock-tracing SiO(5-4) emission extended throughout the filament, and broad turbulent line widths in NH₃(1, 1) through (6, 6), CS(5-4), and SiO(5-4), as well as an increased NH₃ rotational temperature (T_rot) and velocity dispersion (σ) associated with the shocked, blueshifted component. The correlations among T_rot, σ, and V_LSR imply that the shock is accelerating, heating, and adding turbulent energy to the filament gas. Given G23.33-0.30's location within the giant molecular cloud G23.0-0.4, we speculate that the shock and NH₃(3, 3) masers originated from the supernova remnant (SNR) W41, which exhibits additional evidence of an interaction with G23.0-0.4. We have also detected the 1.3 mm dust continuum emission from at least three embedded molecular cores associated with G23.33-0.30. Although the cores have moderate gas masses (M = 7-10 M_☉), their large virial parameters (α = 4-9) suggest that they will not collapse to form stars. The turbulent line widths of the (α > 1) cores may indicate negative feedback due to the SNR shock.