The Structure of the Virgo Cluster from Surface Brightness Fluctuations inHubble Space TelescopeImages

Surface brightness fluctuations (SBF) in Hubble Space Telescope ( HST ) Wide Field Planetary Camera 2 images of elliptical galaxies provide the precision necessary to examine the internal structure of the Virgo galaxy cluster. In a sample of 15 elliptical galaxies with observations from the HST archive, we find that most galaxies are within 2 Mpc of NGC 4486, but several galaxies (including NGC 4406) are significantly in the foreground or background. The measured redshifts and distances suggest that all sample galaxies are gravitationally bound to the galaxy cluster. The SBF distances presented here show good agreement with other SBF distance measurements and with distance measurements made using other methods. We include a brief overview of the SBF method, as well as a more detailed description of the SBF calibration used with the data included in this study, which was taken in the HST F814W filter.