WISH (Wide-field Infrared Surveyor for High-redshift) is a space science mission concept whose primary goal is to study the first galaxies in the early universe. WISH will be a Japan-led 1.5m telescope equipped with a 900 arcmin2 wide-field, Near-IR, 0.2-0.5arcsec FWHM, camera that would fly by ~2020 in order to conduct unique ultra-deep and wide-area sky surveys in the wavelength range 1-5 micron. A spectroscopic parallel-mode spectrograph (WISHSpec, Integral-Field Unit) in the same Near-IR range is also planned and would be studied in France under the responsibility of LAM. Although the instrument design is still open, with the parallel mode, we could envisage very deep exposure times in spectroscopy over (relatively) wide areas.
Several photometric surveys are planned (1000deg2 to AB=25, 100deg2 to AB=28 and 0.25deg2 to AB=29) that should take ~75% of the science telescope lifetime. Spectroscopically, we envision two spectroscopic surveys (10deg2 to ~8×10^-16erg/s and ~8×10^-17erg/s). They will allow to detect the first galaxies to z~15 (if any) and to physically study the first generation of stars spectroscopically at 3<z<10. Beyond the above main science case, WISH would be excessively useful to other themes related to the Programme Nationale Cosmologie et Galaxies (PNCG) and the optimal balance between the major science drivers still needs to be defined. The aim of this workshop is therefore to help defining the science case for WISH and more specifically for the spectrograph WISHSpec by bringing together people interested in this matter. This meeting is planned to be informal with ample time for discussion. Last but not least, WISH will be crucial because it will provide a way of selecting targets of interest for the JWST and the ELTs. It will also be complementary to other missions like Euclid/WFIRST/SPICA by providing deep data in the 1-5 micron range.