Hubble Ultra Deep Parallel Fields

Using an i-z>1.4 cut, we find 30 i-dropouts over 21-arcmin^2^ down to z_(850,AB)_=28.1, or 1.4 i-dropouts arcmin^-2^, with significant field-to-field variation (as expected from cosmic variance).

This extends i-dropout searches some ~0.9mag further down the luminosity function than was possible in the Great Observatories Origins Deep Survey (GOODS) fields, yielding a ~7 times increase in surface density. An estimate of the size evolution for UV-bright objects is obtained by comparing the composite radial flux profile of the bright i-dropouts (z_(850,AB)_<27.2) with scaled versions of the Hubble Deep Field North and South U-dropouts.