THOR-HI (top) observations and their respective filaments from the Hessian analysis (bottom) toward the Galactic longitude range of the region of interest (ROI) A, as defined in Fig. 7. The yellow circles correspond to the positions and sizes of the supernova remnants in the Green (2019) catalog. The cyan circles correspond to the positions and sizes of the HII regions in the Anderson et al. (2014) catalog with v_LSR within ±10 km s⁻¹ of the central velocity indicated in the figure. The magenta crosses mark the position of the THOR OH 1720-MHz masers in that velocity range.