Radial infall onto a massive molecular filament

The newly discovered Massive Molecular Filament (MMF) G32.02+0.05 (∼ 70 pc long, 10⁵ M⊙) has been shaped and compressed by older generations of massive stars. The similarity of this filament in physical structure (density profile, temperature) to much smaller star-forming filaments, suggests that the mechanism to form such filaments may be a universal process. The densest portion of the filament, apparent as an Infrared Dark Cloud (IRDC) shows a range of massive star formation signatures throughout. We investigate the kinematics in this filament and find widespread inverse P cygni asymmetric line profiles. These line asymmetries are interpreted as a signature of large-scale radial collapse. Using line asymmetries observed with optically thick HCO⁺ (1-0) and optically thin H¹³CO⁺ (1-0) across a range of massive star forming regions in the filament, we estimate the global radial infall rate of the filament to range from a few 100 to a few 1000 M⊙ Myr^-1 pc^-1. At its current infall rate the densest portions of the cloud will more than double their current mass within a Myr.