Previous abstract Next abstract
We describe the results of our investigation into possible mechanisms influencing galaxy orientations using position angles and ellipticities for a sample of $\sim1000$ galaxies located in the Pisces-Perseus supercluster. Our data consists of digitized images from POSS I blue and red plates obtained with the Automated Plate Scanner (APS). We fit a 2-dimensional bulge plus disk model to the galaxy images. The resulting position angles and ellipticities are used to investigate whether there is any alignment of galaxy orientations due either to the local tidal field or to the formation mechanisms responsible for the supercluster. Since any modern remnant of the formation history of the supercluster is expected to introduce at best a weak level of modern galaxy alignments, removing biasing is of upmost importance.
K/S tests with approximately one quarter of the expected total dataset indicate a 99\% probability that our overall position angle distribution is random. We will continue checking for alignments over the entire supercluster ridge, but we also plan to perform a test of alignments of nearest neighbor galaxies, both for Pisces-Perseus galaxies and galaxies in the field. This will provide a measure of the observed versus chance alignments. This study should provide the most accurate determination to date of the extent of galaxy alignments due to early formation mechanisms.
Tuesday program listing