CARMA large area star formation survey: Structure and kinematics of dense gas in serpens main

Katherine I. Lee, Manuel Fernández-López, Shaye Storm, Leslie W. Looney, Lee G. Mundy, Dominique Segura-Cox, Peter Teuben, Erik Rosolowsky, Héctor G. Arce, Eve Charis Ostriker, Yancy L. Shirley, Woojin Kwon, Jens Kauffmann, John J. Tobin, Adele L. Plunkett, Marc W. Pound, Demerese M. Salter, N. H. Volgenau, Che Yu Chen, Konstantinos TassisAndrea Isella, Richard M. Crutcher, Charles F. Gammie, Leonardo Testi

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We present observations of N2H+ (J = 1 → 0), HCO+ (J = 1 → 0), and HCN (J = 1 → 0) toward the Serpens Main molecular cloud from the CARMA Large Area Star Formation Survey (CLASSy). We mapped 150 arcmin2 of Serpens Main with an angular resolution of ∼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. Themajority of gas in the two subclusters has subsonic to sonic velocity dispersions.We applied a dendrogram technique with N2H+(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 ∼0.2 pc and widths of ∼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.

Original languageEnglish (US)
Article number76
JournalAstrophysical Journal
Issue number2
StatePublished - Dec 20 2014

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • ISM: clouds
  • ISM: kinematics and dynamics
  • ISM: molecules
  • ISM: structure
  • Stars: formation


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