Miki Kurihara, “Markov-Chain Monte Carlo Fitting of X-ray Light Curves of Active Galactic Nuclei”
Mentors: Sarah Vigeland & Tingting Liu, Physics

Some galaxies in the Universe have a very bright region called Active Galactic Nuclei (AGN) at the center. While AGN has the extreme luminosity compared to other astronomical objects, the number of photons they emit tends to vary according to time. Fitting observed light curve data, which shows its variability, provides us information about the system behind it. We use the Markov-Chain Monte Carlo (MCMC) method to achieve that. We prepared several models, including the power-law and free spectrum. Through the iteration, MCMC tries to find out the best fit parameter set of the model so that the likelihood is maximized. We applied it to data from 30 light curves from the Swift Burst Alert Telescope. As for the power-law model, the results we gained were consistent with the previous independent study.