2006AJ....131...70L

We investigate the ability of infrared integral-field spectrographs to map the velocity fields of high-redshift galaxies, presenting a formalism that can be applied to any telescope and imaging spectrograph system. We discuss the 5 σ limiting line fluxes that current integral-field spectrographs reach and extend this discussion to consider future large-aperture telescopes with cryogenically cooled adaptive reimaging optics. In particular, we simulate observations of spectral line emission from star-forming regions at redshifts z=0.5-2.6 using a variety of spatial sampling scales and give predictions for the signal-to-noise ratio expected as a function of redshift. Using values characteristic of the Keck II telescope and the new OSIRIS spectrograph, we calculate integral-field signal-to-noise ratio maps for a sample of U_nGR color-selected star-forming galaxies at redshift z∼2-2.6 and demonstrate that OSIRIS will be able to reconstruct the two-dimensional projected velocity fields of these galaxies on scales of 100 mas (∼1 kpc at redshift z∼2). With signal-to-noise ratios per spatial sample up to ∼20, OSIRIS will in some cases be able to distinguish between merger activity and ordered disk rotation. Structures on scales smaller than 1 kpc may be detected by OSIRIS for particularly bright sources and will be easy targets for future 30 m class telescopes.