Spectral Templates Optimal for Selecting Galaxies at z > 8 with JWST

Understand

The selection of high-redshift galaxies often involves spectral energy distribution (SED) fitting to photometric data, an expectation for contamination levels, and measurement of sample completeness -- all vetted through comparison to spectroscopic redshift measurements of a sub-sample.

• The first JWST data is now being taken over several extragalactic fields, to different depths and across various areas, which will be ideal for the discovery and classification of galaxies out to distances previously uncharted.
• As spectroscopic redshift measurements for sources in this epoch will not be initially available to compare with the first photometric measurements of z > 8 galaxies, robust photometric redshifts are of the utmost importance.
• Galaxies at z > 8 are expected to have bluer rest-frame ultraviolet (UV) colors than typically-used model SED templates, which could lead to catastrophic photometric redshift failures.