AAS 195th Meeting, January 2000
Session 120. Clusters of Galaxies and Their Contents
Oral, Saturday, January 15, 2000, 10:00-11:30am, Centennial III

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[120.05] Optical Filaments in Elliptical Galaxies and Clusters: Remnants from a Spiral-Elliptical Interaction?

Robert Mohr (University of Alabama)

In the late 70's and early 80's it was suggested that optical filaments were possible indicators of a cluster gas cooling flow. In this theory, the 107 K x-ray emitting intra-cluster mediums (ICM's) of some clusters had cooling times that were less than a Hubble time. As a result, the ICM began to cool and accrete toward the potential well of the cluster, forming 104 K optically emitting filaments. One troublesome feature of this theory was that observationally the filaments are found to be dusty. It was not believed that these dust grains could survive for long enough times within the 107 K environment.

In the late 80's, optical filaments were discovered around apparently isolated elliptical galaxies. Some isolated ellipticals have x-ray halos -- could they also have cooling flows? In a second theory, it was suggested that optical filaments could be the result of an interaction between an elliptical and a gas-rich companion. Observational research supporting this idea included studies of A1795 and the Perseus cluster. In A1795, dwarf galaxies were found at the ends of some of the filaments. In the Perseus cluster, a possible culprit galaxy was identified.

I have made theoretical arguments and self-gravitating computer simulations of a disk galaxy falling into both an isolated elliptical galaxy and a giant elliptical galaxy in a cluster's core. These arguments and simulations consider both ram-pressure stripping and tidal disruption as possible mechanisms for filament formation and dust injection. I compare my results with observations of both A1795 and the Perseus cluster, both of which support the interaction scenario.

I would like to thank Dr. Gene Byrd, Dr. Richard Miller, Dr. Ray White III, and the University of Alabama for supporting me in this work.

The author(s) of this abstract have provided an email address for comments about the abstract: mohr@hera.astr.ua.edu

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