Spectral Templates Optimal for Selecting Galaxies at z > 8 with JWST by Rebecca L. Larson et al. on Monday 21 November

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. We use a combination of BPASS and Cloudy models

to create a supporting set of templates that match the predicted rest-UV colors

of z > 8 the simulated galaxies in a mock catalog (Yung et al. 2022), which

mimics expected field depths and areas of the Cosmic Evolution Early Release

Science Survey (CEERS: m$_{5\sigma}$ ~ 28.6 over ~100 arcmin$^2$; Finkelstein

et al. 2022a, Bagley et al. 2022). We use EAZY to highlight the improvements in

redshift recovery with the inclusion of our new template set and suggest

criteria for selecting galaxies at 8 < z < 10 with JWST, providing an important

test case for observers venturing into this new era of astronomy.

arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.10035v1