TIMES II: Investigating the Relation Between Turbulence and Star-forming Environments in Molecular Clouds

TL;DR

This study uses principal component analysis to explore how star formation influences turbulence in molecular clouds, revealing that active star-forming regions exhibit higher turbulence, especially in dense gas, due to dynamical activities like jets and outflows.

Contribution

It demonstrates the relationship between star formation activity and turbulence levels in different gas densities within molecular clouds using PCA analysis.

Findings

Turbulence is highest in active star-forming regions like ISF and L1688.

Dense gas shows more turbulence than diffuse gas in star-forming areas.

Star formation activities contribute to increased turbulence through jets and outflows.

Abstract

We investigate the effect of star formation on turbulence in the Orion A and Ophiuchus clouds using principal component analysis (PCA). We measure the properties of turbulence by applying PCA on the spectral maps in $^{13}$CO, C$^{18}$O, HCO$^+$ $J=$1$-$0, and CS $J=$2$-$1. First, the scaling relations derived from PCA of the $^{13}$CO maps show that the velocity difference ($\delta v$) for a given spatial scale ($L$) is the highest in the integral shaped filament (ISF) and L1688, where the most active star formation occurs in the two clouds. The $\delta v$ increases with the number density and total bolometric luminosity of the protostars in the sub-regions. Second, in the ISF and L1688 regions, the $\delta v$ of C$^{18}$O, HCO$^+$, and CS are generally higher than that of $^{13}$CO, which implies that the dense gas is more turbulent than the diffuse gas in the star-forming regions; stars form in dense gas, and dynamical activities associated with star formation, such as jets and outflows, can provide energy into the surrounding gas to enhance turbulent motions.