Predictions for deep galaxy surveys with JWST from Λ CDM

We present predictions for the outcome of deep galaxy surveys with the James Webb Space Telescope (JWST) obtained from a physical model of galaxy formation in Lambda cold dark matter. We use the latest version of the GALFORM model, embedded within a new(800 Mpc)(3) dark matter only simulation with a halo mass resolution of M-halo > 2 x 10(9) h(-1) M circle dot. For computing full UV-to-mm galaxy spectral energy distributions, including the absorption and emission of radiation by dust, we use the spectrophotometric radiative transfer code GRASIL. The model is calibrated to reproduce a broad range of observational data at z less than or similar to 6, and we show here that it can also predict evolution of the rest-frame far-UV luminosity function for 7 less than or similar to z less than or similar to 10 which is in good agreement with observations. We make predictions for the evolution of the luminosity function from z = 16 to z = 0 in all broad-band filters on the Near InfraRed Camera (NIRCam) and Mid InfraRed Instrument (MIRI) on JWST and present the resulting galaxy number counts and redshift distributions. Our fiducial model predicts that similar to 1 galaxy per field of view will be observable at z similar to 11 for a 10(4) s exposure with NIRCam. A variant model, which produces a higher redshift of reionization in better agreement with Planck data, predicts number densities of observable galaxies similar to 5 x greater at this redshift. Similar observations with MIRI are predicted not to detect any galaxies at z greater than or similar to 6. We also make predictions for the effect of different exposure times on the redshift distributions of galaxies observable with JWST, and for the angular sizes of galaxies in JWST bands.