Central Surface Brightness Profiles in Brightest Cluster Galaxies

2004 • 2004cbhg.sympE..36L

Authors • Laine, S. • van der Marel, R. P. • Lauer, T. R. • Postman, M. • O'Dea, C. P. • Owen, F. N.

Abstract • We present results from an HST WFPC2 I-band imaging study of the centers of 81 brightest cluster galaxies (BCGs). The images show a rich variety of morphological features. We were able to derive surface brightness profiles for 60 galaxies. Of those, 88% have well-resolved cores. The remaining twelve percent have ``power-law'' profiles. Therefore, the central structure of even the brightest galaxies shows a bimodality. A correlation between the power-law BCGs and the so-called α parameter, related to the slope of the surface brightness profile at a large radius, suggests a scenario in which elliptical galaxies evolve from power-law profiles to core profiles through accretion and merging. This is consistent with theoretical scenarios which invoke the formation of massive black hole binaries during merger events.

Links

• POSTSCRIPT http://www.obs.carnegiescience.edu/ociw/symposia/series/symposium1/ms/laine_ms.ps.gz