From Fluxes to Physical Properties: Understanding the SEDs of galaxies
by
Viviana Acquaviva(Rutgers University)
→
Europe/Stockholm
FA31
FA31
Description
Spectral Energy Distribution (SED) fitting plays a key role in our understanding of a galaxy's physical properties and star formation history. The idea of comparing theoretical templates to observations in order to find which models best resemble the data is simple and powerful; however, it is essential that it is implemented while avoiding biasing assumptions on the shape of the probability distribution function, and while maximizing the accuracy in the reported uncertainties.
MCMC algorithms are suitable statistical tools for this purpose, because they enable efficient, reliable estimation of parameter expectation values and uncertainties and allow one to explore parameter spaces of high dimensionality while minimizing CPU time.
I will introduce GalMC, our publicly available MCMC algorithm for SED fitting, present the results obtained for two stacked samples of Lyman Alpha Emitting galaxies at z ~ 3 from the MUSYC survey, and discuss the dependence of the inferred SED parameters on the assumptions made in modeling the stellar populations.
I will also present GalFish, an algorithm based on the Fisher Matrix formalism that allows one to forecast the achievable constraints on SED fitting parameters extremely quickly before the data are taken. By comparing the predictions obtained by using GalMC and GalFish, I will show that the latter can be used to easily optimize the experimental setup of planned astronomical surveys.
