# The Effect of Noise on the Dust Temperature-Spectral Index Correlation

 Title: The Effect of Noise on the Dust Temperature-Spectral Index Correlation Author: Shetty, Rahul; Kauffmann, Jens; Schnee, Scott; Goodman, Alyssa A. Note: Order does not necessarily reflect citation order of authors. Citation: Shetty, Rahul, Jens Kauffmann, Scott Schnee and Alyssa A. Goodman. 2009. The effect of noise on the dust temperature-spectral index correlation. Astrophysical Journal 696(1): 676-680. Full Text & Related Files: Goodman_EffectNoise.pdf (357.8Kb; PDF) Abstract: We investigate how uncertainties in flux measurements affect the results from modified blackbody spectral energy distribution (SED) fits. We show that an inverse correlation between the dust temperature T and spectral index β naturally arises from least-squares fits due to the uncertainties, even for sources with a single T and $$\beta$$. Fitting SEDs to noisy fluxes solely in the Rayleigh–Jeans regime produces unreliable T and $$\beta$$ estimates. Thus, for long wavelength observations $$(\lambda > \sim 200 \mu m)$$, or for warm sources $$(T >\sim 60 K)$$, it becomes difficult to distinguish sources with different temperatures. We assess the role of noise in recent observational results that indicate an inverse and continuously varying $$T –\beta$$ relation. Though an inverse and continuous $$T –\beta$$ correlation may be a physical property of dust in the interstellar medium, we find that the observed inverse correlation may be primarily due to noise. Published Version: doi:10.1088/0004-637X/696/1/676 Other Sources: http://arxiv.org/abs/0902.0636v2 Terms of Use: This article is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http://nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of-use#OAP Citable link to this page: http://nrs.harvard.edu/urn-3:HUL.InstRepos:4481286 Downloads of this work: