Galaxy Clustering Statistics of medium-Deep Survey WFPC1 and WFPC2 Images
Session 62 -- Large Scale Structures
Display presentation, Thursday, 2, 1994, 10:00-11:30

[62.01] Galaxy Clustering Statistics of medium-Deep Survey WFPC1 and WFPC2 Images

L. W. Neuschaefer, S. C. Casertano, R. E. Griffiths, K. U. Ratnatunga (Johns Hopkins University), R. A. Windhorst (Arizona State University), R. S. Ellis, G. Gilmore (IoA, Cambridge), R. F. Green (NOAO), J. P. Huchra (CfA), G. D. Illingworth, D. C. Koo (UCSC), J. A. Tyson (Bell Labs)

We extend the analysis of the clustering properties of faint galaxies observed in WFPC1 and WFPC2 images obtained by the Medium-Deep Survey Key project. MDS fields are more than 90\% complete for limiting V magnitudes from 22 to 25 mag. The angular two-point correlation function is measured down to 0.5 arcsec scales and Nth-nearest neighbor statistics are measured from 50 WFPC1 fields and 20 WFPC2 fields. This information is used to place limits on the rate of galaxy merging at redshifts in the range 0.3--0.7. Preliminary results show: 1) very weak clustering at V$\sim$25 mag, consistent with earlier deep surveys, which may suggest contraction of galaxy clusters in proper coordinates; and 2) evidence for a small excess of galaxy pairs at $\leq100 h^{-1}kpc$ which suggests only a moderate merging rate out to z$\leq$0.7. Using 35 WFPC1 fields with imaging in both V (F555W) and I (F785LP) we examine trends of clustering versus color. For a subset of these fields measured galaxy parameters, determined from maximum-likelihood fits of disk and bulge models, are used to examine trends of clustering versus galaxy type. We also examine differences between WFPC1 and WFPC2 imaging as it relates to distinguishing interacting galaxies from HII regions within galaxies.