Galaxy Zoo: Star Formation Histories of Barred Galaxies using Structural Decomposition of Galaxy Images
Sandor Kruk
University of Oxford
Chris Lintott (University of Oxford), Brooke Simmons (University of Oxford), Rebecca Smethurst (University of Oxford) And Galaxy Zoo Team
Understanding the effect of the different physical appearances of galaxies on their evolution is crucial in our interpretation of the present day Universe. We study the star formation history of stellar populations in disc galaxy structures (bars, bulges and discs), using morphological classifications from the Galaxy Zoo project. Galaxy Zoo is a highly successful citizen science project that provides probabilistic estimates of morphologies for more than 200,000 galaxies. Using data from the Sloan Digital Sky Survey we have created a representative sample of ~10,000 local disc galaxies (z < 0.06) which have been visually examined by volunteers for the presence of a bar. On these galaxies, we have performed three-component (bar/bulge/disc) parametric decomposition using the 2D fitting algorithm GALFIT. We discuss the use of various surface brightness profiles to model the three components to get the best fits. Using multiple band SDSS images, we investigate the most probable star formation histories of galaxies using a Bayesian analysis approach. We examine the role and importance of the large-scale galactic bars on the star formation history, by splitting the sample into barred and unbarred late-type spirals. Using Galaxy Zoo morphologies we are able to perform 2D bar/bulge/disc decomposition on the largest sample of disc galaxies to date and study the secular evolution of their detailed stellar structures.