High resolution LAsMA $^{12}$CO and $^{13}$CO observation of the G305 giant molecular cloud complex : II. Effect of feedback on clump properties

TL;DR

This study investigates how feedback from OB stars influences the properties of molecular cloud clumps in G305, revealing triggered star formation and differences from the Galactic average through high-resolution CO observations.

Contribution

It provides new insights into feedback effects on clump properties and star formation in G305 using detailed dendrogram analysis and comparison with Galactic samples.

Findings

Clumps inside G305 have higher surface mass densities.

Feedback correlates positively with clump surface densities.

G305's clump mass distribution suggests triggered star formation.

Abstract

G305 star-forming complex was observed in the 3-2 lines of 12 & 13CO to investigate the effect of feedback from the central OB stars on the complex. The region was decomposed into clumps using dendrogram analysis. A catalog of the clump properties was created. The surface mass densities of the clumps were plotted as a function of the incident 8um flux. A mask of the region with 8um flux >100 MJy/sr was created and clumps were categorized based on the extent of overlap with the mask into "mostly inside" , "partly inside'", & "outside". The surface mass density distribution of each of these populations were plotted. This was followed by comparing the G305 clumps with the Galactic average taken from the ATLASGAL and CHIMPS clumps. Finally, the cumulative distribution functions (CDF) of the clump masses in G305 and their L/M ratios were compared to that of the Galactic sample. The surface mass densities of clumps showed a positive correlation with the incident 8um flux. The data did not have sufficient velocity resolution to discern the effects of feedback on the linewidths of the clumps. The sub-sample of clumps named "mostly inside" had the highest surface mass densities followed by "partly inside" and "outside" sub-samples. These differences between the three sub-samples were shown to be statistically significant using the KS test. The "mostly inside" sample also showed the highest level of fragmentation compared to the other two. These prove that the clumps inside the G305 region are triggered. The G305 clump population is also statistically different from the Galactic average population rejecting redistribution as a likely consequence of feedback. The CDFs of clump masses and their L/M ratios are both flatter than the Galactic average, indicating that feedback in G305 has triggered star formation. The collect and collapse method is the dominant mechanism at play in G305.