Astrophys. J., 805, 185 (2015/June-1)
An ammonia spectral map of the L1495-B218 filaments in the Taurus molecular cloud. I. Physical properties of filaments and dense cores.
SEO Y.M., SHIRLEY Y.L., GOLDSMITH P., WARD-THOMPSON D., KIRK J.M., SCHMALZL M., LEE J.-E., FRIESEN R., LANGSTON G., MASTERS J. and GARWOOD R.W.
Abstract (from CDS):
We present deep NH3 observations of the L1495-B218 filaments in the Taurus molecular cloud covering over a 3° angular range using the K-band focal plane array on the 100 m Green Bank Telescope. The L1495-B218 filaments form an interconnected, nearby, large complex extending over 8 pc. We observed NH3(1, 1) and (2, 2) with a spectral resolution of 0.038 km/s and a spatial resolution of 31". Most of the ammonia peaks coincide with intensity peaks in dust continuum maps at 350 and 500 µm. We deduced physical properties by fitting a model to the observed spectra. We find gas kinetic temperatures of 8-15 K, velocity dispersions of 0.05-0.25 km/s, and NH3column densities of 5x1012 to 1x1014/cm2. The CSAR algorithm, which is a hybrid of seeded-watershed and binary dendrogram algorithms, identifies a total of 55 NH3structures, including 39 leaves and 16 branches. The masses of the NH3sources range from 0.05 to 9.5 M☉. The masses of NH3leaves are mostly smaller than their corresponding virial mass estimated from their internal and gravitational energies, which suggests that these leaves are gravitationally unbound structures. Nine out of 39 NH3 leaves are gravitationally bound, and seven out of nine gravitationally bound NH3leaves are associated with star formation. We also found 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.
ISM: clouds - ISM: molecules - radio lines: ISM - stars: formation
Table 1: [SSG2015] NN, [SSG2015] NN.N, [SSG2015] NN.NN, [SSG2015] NN.NNN N=55.
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