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We have used the Taeduk Radio Astronomy Observatory to observe the Orion A and Ophiuchus clouds in the J = 1-0 lines of (CO)-C-13, (CO)-O-18, HCN, HCO+, and N2H+ and the J= 2-1 line of CS. The fully sampled maps with uniform noise levels are used to create moment maps. The variations of the line intensity and velocity dispersion with total column density, derived from dust emission maps, are presented and compared to previous work. The CS line traces dust column density over more than one order of magnitude, and the N2H+ line best traces the highest column density regime (log(NH2) > 22.8). Line luminosities, integrated over the cloud, are compared to those seen in other galaxies. The HCO+-to-HCN luminosity ratio in the Orion A cloud is similar to that of starburst galaxies, while that in the Ophiuchus cloud is in between those of active galactic nuclei and starburst galaxies.

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 (CO)-C-13, (CO)-O-18, HCO+ J = 1-0, and CS J = 2-1. First, the scaling relations derived from PCA of the (CO)-C-13 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 subregions. Second, in the ISF and L1688 regions, the delta v of (CO)-O-18, HCO+, and CS are generally higher than that of (CO)-C-13, 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.

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 (CO)-C-13, (CO)-O-18, HCO+ J = 1-0, and CS J = 2-1. First, the scaling relations derived from PCA of the (CO)-C-13 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 subregions. Second, in the ISF and L1688 regions, the delta v of (CO)-O-18, HCO+, and CS are generally higher than that of (CO)-C-13, 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.

We have used the Taeduk Radio Astronomy Observatory to observe the Orion A and Ophiuchus clouds in the J = 1-0 lines of (CO)-C-13, (CO)-O-18, HCN, HCO+, and N2H+ and the J= 2-1 line of CS. The fully sampled maps with uniform noise levels are used to create moment maps. The variations of the line intensity and velocity dispersion with total column density, derived from dust emission maps, are presented and compared to previous work. The CS line traces dust column density over more than one order of magnitude, and the N2H+ line best traces the highest column density regime (log(NH2) > 22.8). Line luminosities, integrated over the cloud, are compared to those seen in other galaxies. The HCO+-to-HCN luminosity ratio in the Orion A cloud is similar to that of starburst galaxies, while that in the Ophiuchus cloud is in between those of active galactic nuclei and starburst galaxies.