[Previous] | [Session 42] | [Next]
G. A. Wegner (Dartmouth College), J. J. Mohr (University of Illinois)
Relative distances to the galaxy cluster Abell 2199 and two sub-components of the neighboring Abell 2197 cluster, A2197E and A2197W, are derived using the fundamental plane (FP) method from new imaging and spectroscopy obtained using the 2.4 m Hiltner and 3.5 m WIYN telescopes. The new velocity dispersions, \sigma, were combined with the literature data and yield a final sample of 75 early-type galaxies in the clusters. The fundamental planes were fit assuming that the FP parameters are the same, but the clusters are at different distances. For the FP this yields a = 1.25 ± 0.02 and b = 0.34 ±0.01, but the A2197W clump lies 0.05 ±0.01 farther away than A2199 and the smaller A2197E, if separate, is found to be at 0.00 ±0.02. We use the newly measured distances and relative velocities to construct a dynamical model for the complex system. With an estimated virial mass of 1.1 \times 1015 solar masses for the system and an outgoing velocity of about 500 km/s for A2197W relative to A2199, the often used radial infall model cannot provide a bound outgoing orbit for A2197W so a more complicated analysis appears to be required.
[Previous] | [Session 42] | [Next]
Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.