Se-Heon Oh (Korea Astronomy and Space Science Institute)

Se-Heon Oh colloquium: 2D Bayesian Automated Tilted-ring fitting of disk galaxies in large HI galaxy surveys

Abstract

The WALLABY kinematics working group has defined a detailed strategy to parameterise the kinematics of spatially resolved disk-dominated galaxies from ASKAP WALLABY. We designed a conceptual pipeline for extracting reliable galaxy kinematics, utilising three algorithms: 2D tilted-ring analysis and DISKFIT which operate on 2D velocity fields, and TIRIFIC which operates on 3D data cubes. In this talk, I will present a newly developed 2D tilted-ring fitting algorithm based on a Bayesian MCMC technique, the so-called 2DBAT which enables us to derive rotation curves of galaxies in a fully automated manner. Its performance was tested using a sample of galaxies from Local Volume HI Survey (LVHIS) as well as artificial galaxies, correctly recovering their rotation curves derived in manual with standard tilted-ring analysis software. Together with TIRIFIC and DISKFIT, this new Bayesian 2D tilted-ring fitter will comprise the WALLABY kinematics pipeline, and enable us to perform kinematic analysis of an unprecedented number (> 5,000) of resolved galaxies from the upcoming SKA pathfinders' galaxy surveys including ASKAP WALLABY.