The Effect of Noise in Dust Emission Maps on the Derivation of Column Density, Temperature, and Emissivity Spectral Index

We have mapped the central 10'x10' of the dense core TMC-1C at 450, 850 and1200 microns using SCUBA on the James Clerk Maxwell Telescope and MAMBO on theIRAM 30m telescope. We show that although one can, in principle, use images atthese wavelengths to map the emissivity spectral index, temperature and columndensity independently, noise and calibration errors would have to be less than2% to accurately derive these three quantities from a set of three emissionmaps. Because our data are not this free of errors, we use our emission maps tofit the dust temperature and column density assuming a constant value of theemissivity spectral index and explore the effects of noise on the derivedphysical parameters. We find that the derived extinction values for TMC-1C arelarge for a starless core (80 mag Av), and the derived temperatures are low (6K) in the densest regions of the core, using our derived value of beta = 1.8.Comment: 23 pages including 9 figures, accepted by Ap