Rogier Windhorst (ASU), Chris Conselice and Larry Petro (STScI) made realistic simulations of NGST images of galaxies at z=1-15 using as the input data base a systematic imaging survey of 37 nearby galaxies with the Hubble Space Telescope Wide Field and Planetary Camera 2 in the mid-UV filter F300W (centered at 2930 Angstroms).

The local comparison sample is used as benchmark to calculate what to expect for the morphology and surface brightness distribution of faint and distant galaxies in deep NGST fields at z=1-15, assuming no evolution. That is, the HST mid-UV images at z=0 are taken at face value and used to simulate what such objects would have looked like to NGST under realistic observing conditions. At the near-IR wavelengths of NGST, these objects will be observed in their rest frame far- or mid-UV.

Below we show the example of one galaxy for one set of assumptions for telescope and observing parameters. The Windhorst et al article (PDF) contains many more galaxies and different sets of assumptions.

These images show the merger UGC06471 and UGC06472 at different redshifts. The first image is the original HST/WFPC2 F300W image of this z=0.01 galaxy pair. The middle image is the simulated NGST 1.76 micron image if this same galaxy pair was at z=5.0. The right image is for z=12.0 and at a wavelength of 3.81 micron.

The simulations were made assuming a 6m NGST mirror, exposing for one hour. The cosmology was Lambda CDM with a Hubble constant of 70 km/s/Mpc. The full details of models and assumptions are described in the Windhorst et al. article (PDF).