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[71.02] The Physical Conditions for Massive Star Formation: Dust Continuum Maps and Modeling

K. E. Mueller, Y. L. Shirley, N. J. Evans II, H. R. Jacobson (Uni. of Texas)

Fifty-one dense cores associated with water masers were mapped at 350 \micron. These cores are very luminous, 10³ < L/L_\odot < 10⁶, indicative of the formation of massive stars. Dust continuum contour maps and radial intensity profiles are presented for a sample of sources. The spectral energy distributions (SEDs) and normalized radial profiles of dust continuum emission were modeled for 28 sources using a one-dimensional dust radiative transfer code, assuming a power law density distribution in the envelope, n = n_f (r/r_f)^-p. The best-fit density power law exponent, p, ranged from 0.75 to 2.5 with \langle p \rangle = 1.72 ±0.37. Different mass estimates are compared and mean masses are reported within a half-power radius determined from the dust emission, \langle {\rm log} M( < r₃₅₀ ) \rangle = 2.0 ± 0.6, and from CS emission, \langle {\rm log} M( < r_CS ) \rangle = 2.2 ± 0.6. Our results are compared with previous work on different samples, and we examine possible evolutionary indicators for regions forming massive stars. Additionally, for comparison with extragalactic star formation studies, the luminosity to mass ratio is calculated for these sources, \langle L_obs/M_iso \rangle = 1100 ±1230 L_\odot/M_\odot, with a method most parallel to that used in studies of distant galaxies.

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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.