Adding Value to JWST Spectra and Photometry: Stellar Population and Star
Formation Properties of Spectroscopically Confirmed JADES and CEERS Galaxies
at z>7
In this paper, we discuss measurements of the stellar population and star
forming properties for 43 spectroscopically confirmed publicly available
high-redshift z>7 JWST galaxies in the JADES and CEERS observational
programs. We carry out a thorough study investigating the relationship between
spectroscopic features and photometrically derived ones, including from
spectral energy distribution (SED) fitting of models, as well as morphological
and structural properties. We find that the star formation rates (SFRs)
measured from Hβ line emission are higher than those estimated from
Bayesian SED fitting and UV luminosity, with ratios SFRHβ​/ SFRUV​
ranging from 2~13. This is a sign that the star formation history is
consistently rising given the timescales of Hβ vs UV star formation
probes. In addition, we investigate how well equivalent widths (EWs) of
Hβλ4861, [O III] λ4959, and [O III] λ5007 can be
measured from photometry, finding that on average the EW derived from
photometric excesses in filters is 30% smaller than the direct spectroscopic
measurement. We also discover that a stack of the line emitting galaxies shows
a distinct morphology after subtracting imaging that contains only the
continuum. This gives us a first view of the line or ionized gas emission from
z>7 galaxies, demonstrating that this material has a similar distribution,
statistically, as the continuum. We also compare the derived SFRs and stellar
masses for both parametric and non-parametric star formation histories, where
we find that 35% of our sample formed at least 30% of their stellar mass in
recent (< 10 Myr) starburst events.Comment: 17 Pages, 13 Figures, 4 Tables, submitted to MNRA