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تسجيل مستخدم جديدInfrared Surface Brightness Distances to Cepheids: a comparison of Bayesian and linear-bisector calculations
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We have compared the results of Bayesian statistical calculations and linear-bisector calculations for obtaining Cepheid distances and radii by the infrared surface brightness method. We analyzed a set of 38 Cepheids using a Bayesian Markov Chain Monte Carlo method that had been recently studied with a linear-bisector method. The distances obtained by the two techniques agree to 1.5 pm 0.6% with the Bayesian distances being larger. The radii agree to 1.1% pm 0.7% with the Bayesian determinations again being larger. We interpret this result as demonstrating that the two methods yield the same distances and radii. This implies that the short distance to the LMC found in recent linear-bisector studies of Cepheids is not caused by deficiencies in the mathematical treatment. However, the computed uncertainties in distance and radius for our dataset are larger in the Bayesian calculation by factors of 1.4-6.7. We give reasons to favor the Bayesian computations of the uncertainties. The larger uncertainties can have a significant impact upon interpretation of Cepheid distances and radii obtained from the infrared surface brightness method.
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Bayesian statistical calculations and linear-bisector calculations for obtaining Cepheid distances and radii by the infrared surface brightness method have been compared for a set of 38 Cepheids. The distances obtained by the two techniques agree to
1.5%+/-0.6% and the radii agree to 1.1%+/-0.7%. Thus the two methods yield the same distances and radii at the 2 sigma level. This implies that the short distance to the LMC found in recent linearbisector studies of Cepheids is not a result of simplifications in the mathematical approach. The computed uncertainties in distance and radius are larger in the Bayesian calculation typically by a factor of three.
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