We investigate how uncertainties in flux measurements affect the results from modified blackbody SED fits. We show that an inverse correlation between the dust temperature T and spectral index (beta) 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 >~ 200 micron), or for warm sources (T >~ 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 ISM, we find that the observed inverse correlation may be primarily due to noise.
@article{arxiv.0902.0636,
title = {The Effect of Noise on the Dust Temperature - Spectral Index Correlation},
author = {Rahul Shetty and Jens Kauffmann and Scott Schnee and Alyssa A. Goodman},
journal= {arXiv preprint arXiv:0902.0636},
year = {2011}
}
Comments
14 pages, including 5 Figures; Accepted for publication in ApJ