Session 12 - Cosmology, Large-Scale Structure and Distance Scales.
Display session, Monday, June 10
Great Hall,

## [12.13] The Distance to NGC4478 using the Surface Brightness Fluctuation method on HST images

E. Neilsen, Z. Tsvetanov, H. Ford (JHU)

We calculate the distance to NGC 4478 using the surface brightness fluctuations method on parallel data form the Hubble Space Telescope WFPC2 camera. The exposures considered were taken through the F814W filter, which approximates the Johnson I, and through the F606W filter (wide V). We describe the use of Fourier methods for separation of the fluctuations due to statistical variations in the projected number of stars per pixel (which is used to determine the distance) from variations from other sources, which include photon noise, foreground stars, globular clusters, cosmic rays, and variations in the overall structure of the galaxy. We obtain a distance of 16.4 \pm 0.9 Mpc from the F814W images, which is consistent with the distance determined through the use of this method in the K band by Parhe amp; Mould (1994). We report progress our examination of the (approximately 50) globular clusters present in these images, which may also be used as a distance indicator for NGC4478.