The Effect of Line-of-Sight Temperature Variation and Noise on Dust Continuum Observations

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The Effect of Line-of-Sight Temperature Variation and Noise on Dust Continuum Observations

Show simple item record Shetty, Rahul Kauffmann, Jens Schnee, Scott Goodman, Alyssa A. Ercolano, Barbara 2010-07-02T13:25:59Z 2009
dc.identifier.citation Rahul, Shetty, Jens Kauffmann, Scott Schnee, Alyssa A. Goodman, and Barbara Ercolano. 2009. The effect of line-of-sight temperature variation and noise on dust continuum observations. Astrophysical Journal 696(2): 2234-2251. en_US
dc.identifier.issn 0004-637X en_US
dc.description.abstract We investigate the effect of line-of-sight temperature variations and noise on two commonly used methods to determine dust properties from dust-continuum observations of dense cores. One method employs a direct fit to a modified blackbody spectral energy distribution (SED); the other involves a comparison of flux ratios to an analytical prediction. Fitting fluxes near the SED peak produces inaccurate temperature and dust spectral index estimates due to the line-of-sight temperature (and density) variations. Longer wavelength fluxes in the Rayleigh-Jeans part of the spectrum \((>{\sim} 600 \mu m\) for typical cores) may more accurately recover the spectral index, but both methods are very sensitive to noise. The temperature estimate approaches the density-weighted temperature, or "column temperature," of the source as short wavelength fluxes are excluded. An inverse temperature-spectral index correlation naturally results from SED fitting, due to the inaccurate isothermal assumption, as well as noise uncertainties. We show that above some "threshold" temperature, the temperatures estimated through the flux ratio method can be highly inaccurate. In general, observations with widely separated wavelengths, and including shorter wavelengths, result in higher threshold temperatures; such observations thus allow for more accurate temperature estimates of sources with temperatures less than the threshold temperature. When only three fluxes are available, a constrained fit, where the spectral index is fixed, produces less scatter in the temperature estimate when compared to the estimate from the flux ratio method. en_US
dc.description.sponsorship Astronomy en_US
dc.language.iso en_US en_US
dc.publisher American Astronomical Society en_US
dc.relation.isversionof doi:10.1088/0004-637X/696/2/2234 en_US
dc.relation.hasversion en_US
dash.license OAP
dc.subject dust en_US
dc.subject extinction en_US
dc.subject infrared: ISM en_US
dc.subject ISM: clouds en_US
dc.subject methods: miscellaneous en_US
dc.subject stars: formation en_US
dc.title The Effect of Line-of-Sight Temperature Variation and Noise on Dust Continuum Observations en_US
dc.type Journal Article en_US
dc.description.version Accepted Manuscript en_US
dc.relation.journal Astrophysical Journal en_US Goodman, Alyssa A. 2010-07-02T13:25:59Z

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