Insights into bulge evolution during the last ~10 Gyrs.
Witnessing Disc Galaxy Evolution Through The Eyes of their Stellar Structures
Joshua Argyle
University of St Andrews
J. Mendéz-Abreu & V. Wild
Bulges of disc galaxies are theorised to play a pivotal role in the evolution of their host. However, the formation of the bulge and its relation to the galaxy size and mass distribution remains poorly understood. The evolution of bulges since z ∼ 2 is thought to be mainly driven by two competitive processes: secular vs. externally triggered events. These leave differing imprints, especially in the morphology and kinematics of the bulge population. We present the results of a study of the structural evolution of disc galaxies over the redshift range 0 < z < 2, with focus on the central regions. With the aid of extensive simulations of galaxy images, we have carefully selected comparable samples situated in suitable redshift regimes. Our analysis is based on a bulge-disc decomposition of ~300 galaxies with M* > 10^9 M ⊙ taken from CANDELS WFC3/IR imaging within COSMOS, in the range 0.5 < z < 2, with comparisons to galaxies at z = 0.02-0.2 from SDSS. We utilise a new adaptive Markov Chain Monte Carlo (MCMC) algorithm with inbuilt diagnostic tests to achieve fast convergence and parameter estimates. This offers a powerful investigative tool for these high redshift galaxies where the parameter space becomes poorly constrained due to the limited signal-to-noise and resolution. A description and interpretation of the structural evolution of disc galaxies over the past 10 billion years will be presented.
09:00 - 10:30