BWFields: Identification and Analysis of Enclosed Molecular Bubbles by Weight Fields

BWFields constructs a three-dimensional bubble-weight field, $W_{l,b,v}$, which accumulates topological evidence for cavity interiors across multiple signal-to-noise tiers and velocity-integration scales. Coherent cavity interiors are segmented as weight-clumps and associated with surrounding molecular gas, linking candidate bubbles to the structure of their host clouds. The shell morphology is characterised through a two-stage procedure. An initial set of radial intensity profiles, modeled with constrained double-Gaussian fitting, provides first-order estimates of shell radius, thickness, and symmetry. These parameters are then used to extract an emission-defined intensity skeleton via azimuth--radius unwrapping and graph-based ridge tracing, which traces the shell crest and refines the geometric description. A second radial-profile analysis based on the skeleton yields updated morphological parameters that are directly coupled to the kinematic analysis. Bubble kinematics are quantified using azimuthally sampled PV diagnostics and a turbulence-normalised expansion significance. BWFields establishes a scalable and physically interpretable framework for molecular-bubble studies in large surveys, enabling systematic investigations of stellar feedback in the Galactic interstellar medium.