We present observations of N _ { 2 } H ^ { + } ( J = 1 \rightarrow 0 ) , HCO ^ { + } ( J = 1 \rightarrow 0 ) , and HCN ( J = 1 \rightarrow 0 ) toward the Serpens Main molecular cloud from the CARMA Large Area Star Formation Survey ( CLASSy ) .
We mapped 150 square arcminutes of Serpens Main with an angular resolution of \sim 7″ .
The gas emission is concentrated in two subclusters ( the NW and SE subclusters ) .
The SE subcluster has more prominent filamentary structures and more complicated kinematics compared to the NW subcluster .
The majority of gas in the two subclusters has subsonic to sonic velocity dispersions .
We applied a dendrogram technique with N _ { 2 } H ^ { + } ( 1-0 ) to study the gas structures ; the SE subcluster has a higher degree of hierarchy than the NW subcluster .
Combining the dendrogram and line fitting analyses reveals two distinct relations : a flat relation between nonthermal velocity dispersion and size , and a positive correlation between variation in velocity centroids and size .
The two relations imply a characteristic depth of 0.15 pc for the cloud .
Furthermore , we have identified six filaments in the SE subcluster .
These filaments have lengths of \sim 0.2 pc and widths of \sim 0.03 pc , which is smaller than a characteristic width of 0.1 pc suggested by Herschel observations .
The filaments can be classified into two types based on their properties .
The first type , located in the northeast of the SE subcluster , has larger velocity gradients , smaller masses , and nearly critical mass-per-unit-length ratios .
The other type , located in the southwest of the SE subcluster , has the opposite properties .
Several YSOs are formed along two filaments which have supercritical mass per unit length ratios , while filaments with nearly critical mass-per-unit-length ratios are not associated with YSOs , suggesting that stars are formed on gravitationally unstable filaments .