Giant molecular filaments in the Milky Way

摘要: Context. Filamentary structures are common morphological features of the cold, molecular interstellar medium (ISM). Recent studies have discovered massive, hundred-parsec-scale filaments that may be connected to large-scale, Galactic spiral arm structure. Addressing nature these giant (GMFs) requires a census their occurrence and properties. Aims: We perform systematic search GMFs in fourth quadrant determine basic physical Methods: identify based on dust extinction signatures near- mid-infrared velocity structure probed by 13CO line emission. use emission ATLASGAL data estimate total dense gas masses GMFs. combine our sample with an earlier from literature study environment Results: nine quadrant: six Centaurus three inter-arm regions. Combining this using same identification criteria first results 16 GMFs, which located within arms. The sizes 80-160 pc 13CO-derived between 5-90 × 104M⊙. Their mass fractions 1.5-37%, is higher also compare different GMF-identification methods find extinction-based techniques overlap only partially, thereby highlighting need both achieve complete census.