Density and Temperature Structure of TMC-1C from 450 and 850 micron Maps

Abstract

We have mapped the central 10'x10' of the dense core TMC-1C at 450 and 850 microns using SCUBA on the James Clerk Maxwell Telescope. The unusually high quality of the 450 micron map allows us to make a detailed analysis of the temperature and column density profiles of the core. We find that the dust temperature at the center of TMC-1C is 7 K, rising to 11 K at the edges. We discuss the possibility and effects of a variable emissivity spectral index on the derived mass profile. The low dust temperature of TMC-1C results in a high derived mass for the core, significantly larger than the virial mass estimated from the linewidth of the N2H+ (1-0) transition. This result is valid within a wide range of dust properties and ellipticities of the core. The N2H+ (1-0) spectra, taken with the IRAM 30m telescope, show signs of self-absorption, which provide evidence of sub-sonic infall motions. The derived density profile and infall velocity is compared to the predictions of several popular star formation models, and the Bonnor-Ebert model isthe best fit analytic model.

38 pages, 13 Figures, accepted to ApJ