paper

Seeking Edge-on Galaxies with Substantial Extraplanar Dust Using a Radiative Transfer Model: Determination of the Model Parameter Uncertainties for EON_10.477_41.954 (FGC 79)

arXiv:1909.00550 · doi:10.1093/mnras/stz2442

Abstract

We have revisited the target EON_10.477_41.954 in order to determine more accurately the uncertainties in the model parameters that are important for target classification (i.e., galaxies with or without substantial extraplanar dust). We performed a Markov-Chain Monte Carlo (MCMC) analysis for the fifteen parameters of the three-dimensional radiative-transfer galaxy model we used previously for target classification. To investigate the convergence of the MCMC sampling---which is usually neglected in the literature but should not be---we monitored the integrated autocorrelation time (), and we achieved effective sample sizes for all the model parameters. The confidence intervals are unstable at the beginning of the iterations where the values of are increasing, but they become stable in later iterations where those values are almost constant. The final confidence intervals are times larger than the nominal uncertainties used in our previous study (the standard deviation of three best-fit results). Thus, those nominal uncertainties are not good proxies for the model-parameter uncertainties. Although the position of EON_10.477_41.954 in the target-classification plot (the scale-height to diameter ratio of dust vs that of light-source) decreases by about % when compared to our previous study, its membership in the ``high-group''---i.e., among galaxies with substantial extraplanar dust---nevertheless remains unchanged.

18 pages, 12 figures, 3 tables, MNRAS in press

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