http://arxiv.org/abs/1808.01129
Huang et al. [arXiv:1804.03101] have analysed the population of known galactic Double Neutron Stars (DNSs) regarding the total masses of these systems. They suggest the existence of two sub-populations, and report likelihood-based preference for a two-component Gaussian mixture model over a single Gaussian distribution. This note offers a cautionary perspective on model selection for this data set: A pure likelihood ratio test can encourage overfitting, which can be avoided by penalising models with a higher number of free parameters. Re-examining the DNS total mass data set within the class of Gaussian mixture models, this is achieved through several simple and well-established statistical tests, including information criteria (AICc, BIC), cross-validation and Bayesian evidence ratios. While this re-analysis confirms the basic finding that a two-component mixture is consistent with the data, the model selection criteria consistently indicate that there is no robust preference for it over a single-component fit. Additional DNS discoveries will be needed to settle the question of sub-populations.
D. Keitel
Mon, 6 Aug 18
11/33
Comments: 8 pages and 10 figures including appendices, comments welcome
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