A highly flattened stellar disk in the elliptical galaxy NGC 4564

Abstract

We present the R band isophotal shape analysis of the E6 elliptical galaxy NGC 4564 by fittng ellipses to the observed isophotes using Fourier expansion procedure. The galaxy is found to have pointy isophotes, showing excess light along its major axis throughout the range of radii. An examination of the residual image obtained by subtracting a smooth elliptical model from the original galaxy image leads to the detection of a fairly prominent stellar disk along its apparent major axis. We use an iterative method to decompose the surface brightness profile into a pure elliptical bulge, obeying de Vaucouleurs law and an exponential disk to derive the best fit parameters of the two components. The stellar disk is highly flattened in consistent with the kinematics of the galaxy.