Weak disks in rapidly rotating elliptical galaxies

Carter, D. 1987, Ap. J. 312, 514.

An ellipse-fitting and Fourier analysis technique is used to search for systematic deviations of the isophotes of rapidly rotating elliptical galaxies from ellipses. Three or four of the galaxies show such deviations, and this is interpreted as evidence for the presence of weak disks within these galaxies. A model of NGC 4697, the galaxy which shows the strongest deviations, as the superposition of a de Vaucouleurs law spheroid and an exponential disk inclined at 10 deg to the line of sight explains the observations well. The disk luminosity in this model is 2.1 percent of the total. Such disks could also be present in other rapidly rotating elliptical galaxies, but if they were inclined at 30 deg or more to the line of sight they would be very hard to detect. The inclination-corrected peak surface brightness of the disk is 21.55 mag/sq arcsec in B.