4-8 October 2015
Hans Harnack Haus
Europe/Berlin timezone
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Contribution Poster

Poster session

L1495-B218 Filaments in Taurus seen in NH$_3$ and CCS


  • Mr. Youngmin SEO

Primary authors



We present NH$_3$ and CCS observations of the L1495-B218 filaments in the Taurus molecular cloud covering over a 3 degree angular range using the K-band focal plane array on the 100m Green Bank Telescope. The L1495-B218 filaments form an interconnected, nearby, large complex extending over 8 pc. We observed NH$_3$ (1,1) \& (2,2) and CCS 2$_1$ $-$ 1$_2$ with a spectral resolution of 0.038 km/s and a spatial resolution of 31$''$. Most of NH$_3$ peaks coincide with intensity peaks in dust continuum maps at 500 $\mu$m, while only three regions, B216, L1495A and east of B213, are bright in CCS. B216 (L1521B) is bright in CCS but dim in NH$_3$ with no protostar, which suggests that it is chemically young. The other two bright CCS regions are actively forming stars and have bright NH$_3$ cores with CCS envelopes and strong infall signatures in HCN and HCO$^+$ 1-0, suggesting that these two regions are accreting new materials from surroundings cloud. We analyze the properties of 55 NH$_3$ structures including 39 leaves and 16 branches that are identified using the CSAR algorithm, which is a hybrid of seeded-watershed and binary dendrogram algorithms. Through a virial analysis of NH$_3$ leaves, we found that only 9 out of 39 NH$_3$ leaves are gravitationally bound and that 12 out of 30 gravitationally unbound leaves are pressure-confined. Our data suggest that a dense core may form as a pressure-confined structure, evolve to a gravitationally bound core, and undergo collapse to form a protostar.