Properties of Field Galaxies to $I=22$ from the Medium Deep Survey
Session 106 -- Galaxies: Photometry and Spectrophotometry
Display presentation, Thursday, 12, 1995, 9:20am - 6:30pm

## [106.09] Properties of Field Galaxies to $I=22$ from the Medium Deep Survey

A. C. Phillips, D. A. Forbes, C. Gronwall, G. D. Illingworth, D. C. Koo (Lick Obs., UCSC), R. E. Griffiths, K. Ratnatunga (JHU), R. S. Ellis (IoA, Cambridge Univ.), R. F. Green (NOAO), J. P. Huchra (CfA), J. A. Tyson (Bell Labs), R. A. Windhorst (ASU)

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We present a complete sample of 72 $I\lesssim 22$ field galaxies from two fields observed with the WFPC-II as part of the Medium Deep Survey. Basic observable parameters ($I$ and $V$ photometry, sizes and intensity profiles) have been measured, and are discussed in the context of morphological type and apparent structural peculiarities. The median redshift of the sample is expected to be z$\sim$0.5. Despite lookback times approaching half the age of the universe, we find little evidence for strong evolutionary effects. In particular, we see no extreme color gradients in the galaxies. The size-vs-magnitude relationship shows no indication that this distant sample differs strongly from the local galaxy population, beyond changes predicted by passive evolution and assuming a local luminosity function improved from that of Koo, Gronwall \& Bruzual (1993).

(This work was supported by NASA/HST grants GO-2684-0*-94A from STScI, which is operated by AURA, Inc., under NASA contract NAS5-26555.)