Outflow and Infall in a Sample of Massive Star Forming Regions II: Large Scale Kinematics

TL;DR

This study maps large-scale kinematics in massive star-forming regions, revealing infall and outflow dynamics, mass transfer rates, and shock luminosities, advancing understanding of massive star formation processes.

Contribution

It provides detailed measurements of infall and outflow regions, mass rates, and shock luminosities in multiple massive star-forming regions, using new SiO and HCO+ observations.

Findings

Four sources show infall signatures.

Outflow and infall mass ratio less than one.

Large-scale infall rate comparable to small-scale rate.

Abstract

We present maps of seven sources selected from Klaassen & Wilson (2007a) in SiO (J=8-7) and HCO$^+$ and H$^{13}$CO$^+$ (J=4-3) which were obtained using HARP-B on the James Clerk Maxwell Telescope. We find that four out of our seven sources have infall signatures based on their HCO$^+$ emission profiles. From our maps, we have determined the extent of both the outflowing and infalling regions towards these sources, and constrained the amount of infalling and outflowing mass as well as the mass infall rate for each massive star forming region. From our SiO observations, we estimate the source luminosity required to shock the surroundings of these massive star forming regions and find luminosities similar to those of the HII regions themselves. We find that the ratio between our infall and outflow masses is less than one, suggesting high mass entrainment rates in the molecular outflows. We also find that the large scale molecular infall rate towards G10.6-0.4 is comparable to the small scale molecular infall rate found in previous studies.