The CANDELS-Area Prism Epoch of Reionization Survey (CAPERS)

JWST provides transformational new capabilities for surveying galaxy evolution during the early phases of cosmic history. Multi-band imaging with NIRCam is revealing an unexpectedly bright population of galaxy candidates at z > 9.5, more abundant than most theoretical models had predicted. NIRCam also images a richly diverse population of galaxies at 4 < z < 9.5 at rest-frame optical wavelengths that can be observed by HST only at z < 3. Spectroscopy with NIRSpec is the essential next step beyond imaging to confirm the most distant galaxy candidates, to determine accurate redshifts needed to robustly quantify galaxy statistics and map large scale structure, to measure physical conditions of the interstellar medium and detailed stellar population properties, and to diagnose the history of reionization using direct measurements of the Lyman alpha damping wing and its evolution. Our proposed CANDELS-Area Prism Epoch of Reionization Survey (CAPERS) will obtain deep NIRSpec prism observations to confirm or refute more than 100 z > 9.5 galaxy candidates identified in three wide-field public NIRCam survey fields from CEERS and PRIMER, while also measuring redshifts for approximately 2000 galaxies selected by NIRCam imaging of optical rest-frame light at 4 < z < 9.5, and 10000 galaxies at all redshifts. CAPERS will build a spectroscopic legacy data set that will serve as a resource for studying galaxy evolution and as a foundation for further, future detailed spectroscopy with JWST's NIRSpec and MIRI and with millimeter and radio observatories.