James Webb Space Telescope Feed Post

Harvard ADS: Performance of Photometric Template Fitting for Ultra-High Redshift Galaxies

Paper abstract: JWST has allowed the discovery of a significant population of galaxies at z > 10. Our understanding of the astrophysical properties of these ultra-high redshift galaxies relies on fitting templates, developed using astrophysical models representing our current understanding of high-redshift galaxies. In this work, the highest confidence recent JWST spectroscopic observations are used to evaluate the performance of several high-redshift templates based on two tests: (1) comparing photometric redshifts against spectroscopic redshifts; and (2) comparing the reconstructed spectral energy distributions against observed SEDs. Strict sample selection and error-propagation by bootstrapping is employed to make results robust towards future JWST systematics mitigation. It is shown that some templates perform adequately at high redshift prediction, given a sample selection by observational filters and depth. Other templates work better for SED fitting, but a few objects remain unrepresented in their spectra. We conclude that although templates are usable, models are not yet able to reliably extract astrophysical properties.