Estimation of Distance of the Triangulum Galaxy using Light Curves of Miras Variable Stars by Jianhua Huang
Estimation of distances of galaxies is one essential component to determine the age and composition of our Universe. The Triangulum Galaxy (catalogued as M33) is the third-largest member of the Local Group of galaxies, and one of the most distant permanent objects that can be viewed with the naked eyes. Mira variable stars are a class of pulsating stars characterized by very red colors. In an interdisciplinary project, we used available light curve data to infer the periods and period-luminosity relations (PLR) of Miras in M33, and then infer the distance of M33 by referencing to the known distance of the LMC, a satellite galaxy of the Milky Way. In this talk, I shall discuss various challenges we faced in this project, including dealing with data sparsity, conducting genuine simulation, reducing computational cost, and quantifying uncertainty. I shall also show how statistical ideas were brought into play in dealing with these challenges. The statistical concepts or methods used include Gaussian process regression, semi-parametric inference, Bayesian hierarchical models, and stochastic variational inference.