Using GALFIT to Determine Galaxy Morphologies of Quasars

POSTER

Abstract

Little is known about the morphologies of quasars. Quasars are the brightest of the active galaxies, in which a supermassive black hole is accreting material, creating an accretion disk that outshines the host galaxy. We model images obtained from the Hubble Space Telescope of 22 nearby quasars and the galaxies in their immediate neighborhood using the GALFIT software to determine how well they are fit by typical galaxy profiles. GALFIT is an image analysis algorithm which fits parametric functions to create light profiles from two-dimensional images. We fit the quasars using two main components - a Point Spread Function (PSF), which represents a point source object (the light of the accretion disk), and a Sérsic profile, which models galaxy structures, such as a disk or a bulge. We will present details on the models, including the types of components used in each fit as well as the residual maps after subtracting the model from the data.

*Support for this work was provided by the department of Physics and Astronomy at the University of Northern Colorado and by NASA through a grant from the Space Telescope Science Institute (Program GO-11557), which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555.

Presenters

  • Kaitlyn Raub

    • Physics and Astronomy, University of Northern Colorado

Authors

  • Kaitlyn Raub

    • Physics and Astronomy, University of Northern Colorado

  • Mariana Lazarova

    • Physics and Astronomy, University of Northern Colorado

  • Gabriele Canalizo

    • Physics and Astronomy, University of California Riverside

  • Mark Lacy

    • National Radio Astronomy Observatory, National ALMA Science Center