A publishing partnership

A Photometric Method for Quantifying Asymmetries in Disk Galaxies

, , and

© 1998. The American Astronomical Society. All rights reserved. Printed in U.S.A.
, , Citation David A. Kornreich et al 1998 AJ 116 2154 DOI 10.1086/300598

1538-3881/116/5/2154

Abstract

A photometric method for quantifying deviations from axisymmetry in optical images of disk galaxies is applied to a sample of 32 face-on and nearly face-on spirals. The method involves comparing the relative fluxes contained within trapezoidal sectors arranged symmetrically about the galaxy center of light, excluding the bulge and/or barred regions. Such a method has several advantages over others, especially when quantifying asymmetry in flocculent galaxies. Specifically, the averaging of large regions improves the signal-to-noise in the measurements; the method is not strongly affected by the presence of spiral arms; and it identifies the kinds of asymmetry that are likely to be dynamically important. Application of this "method of sectors" to R-band images of 32 disk galaxies indicates that about 30% of spirals show deviations from axisymmetry at the 5 σ level.

Export citation and abstract BibTeX RIS

Please wait… references are loading.
10.1086/300598