Gravitational collapse and accretion flows in the hub filament system G323.46-0.08

TL;DR

This study investigates the dynamics of the hub filament system G323.46-0.08, revealing gravitational collapse, filamentary accretion flows, and their role in forming a central high-mass star-forming clump.

Contribution

It provides new observational evidence of filamentary accretion flows feeding a high-mass star-forming region, supported by velocity gradient analysis and model fitting.

Findings

Filaments show large-scale velocity gradients channeling material into the central clump.

The accretion rate onto the clump is estimated at 1216 M Myr-1.

PV diagrams reveal gravitational collapse signatures and mass accretion along filaments.

Abstract

We studied the hub filament system G323.46-0.08 based on archival molecular line data from the SEDIGISM 13CO survey and infrared data from the GLIMPSE, MIPS, and Hi-GAL surveys. G323.46-0.08 consists of three filaments, F-north, F-west, and F-south, that converge toward the central high_mass clump AGAL 323.459-0.079. F-west and Part 1 of the F-south show clear large-scale velocity gradients 0.28 and 0.44 km s-1 pc-1, respectively. They seem to be channeling materials into AGAL 323.459-0.079. The minimum accretion rate was estimated to be 1216 M Myr-1. A characteristic V-shape appears around AGAL 323.459-0.079 in the PV diagram, which traces the accelerated gas motions under gravitational collapse. This has also been supported by model fitting results. All three filaments are supercritical and they have fragmented into many dense clumps. The seesaw patterns near most dense clumps in the PV diagram suggests that mass accretion also occurs along the filament toward the clumps. Our results show that filamentary accretion flows appear to be an important mechanism for supplying the materials necessary to form the central high-mass clump AGAL 323.459-0.079 and to propel the star forming activity taking place therein.