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Combining the public JWST /NIRCam imaging programs CEERS, PRIMER, and JADES, spanning a total area of |$\sim 500\, {\rm arcmin}^2$|⁠ , we obtain a sample of |$\gt $| 30 000 galaxies at |$z_{\rm phot}\sim 4\!-\!9$| that allows us to perform a complete, rest-optical-selected census of the galaxy population at |$z\gt 3$|⁠. Comparing the stellar mass |$M_*$| and the UV-slope |$\beta$| distributions between JWST - and HST -selected samples, we generally find very good agreement and no significant biases. Nevertheless, JWST enables us to probe a new population of UV-red galaxies that was missing from previous HST -based Lyman-break galaxy (LBG) samples. We measure galaxy stellar mass functions (SMFs) at |$z\sim 4\!-\!9$| down to limiting masses of |$10^{7.5}\!-\!10^{8.5}\, {\rm M_\odot }$|⁠ , finding steep low-mass slopes over the entire redshift range, reaching values of |$\alpha \approx -2$| at |$z\gtrsim 6$|⁠. At the high-mass end, UV-red galaxies dominate at least out to |$z\sim 6$|⁠. The implied redshift evolution of the SMF suggests a rapid build-up of massive dust-obscured or quiescent galaxies from |$z\sim 6$| to |$z\sim 4$| as well as an enhanced efficiency of star formation towards earlier times (⁠|$z\gtrsim 6$|⁠). Finally, we show that the galaxy mass density grows by a factor |$\sim 20\times$| from |$z\sim 9$| to |$z\sim 4$|⁠. Our results emphasize the importance of rest-frame optically selected samples in inferring accurate distributions of physical properties and studying the mass build-up of galaxies in the first 1.5 Gyr of cosmic history. [ABSTRACT FROM AUTHOR]

The physical properties of galaxies are encoded within their spectral energy distribution and require comparison with models to be extracted. These models must contain a synthetic stellar population and, where infrared data are to be used, also consider prescriptions for energy reprocessing and re-emission by dust. While many such models have been constructed, there are few analyses of the impact of stellar population model choice on derived dust parameters, or vice versa. Here, we apply a simple framework to compare the impact of these choices, combining three commonly used stellar population synthesis models and three dust emission models. We compare fits to the ultraviolet to far-infrared spectral energy distributions of a validation sample of infrared-luminous galaxies. We find that including different physics, such as binary stellar evolution, in the stellar synthesis model can introduce biases and uncertainties in the derived parameters of the dust and stellar emission models, largely due to differences in the far-ultraviolet emission available for reprocessing. This may help to reconcile the discrepancy between the cosmic star formation rate and stellar mass density histories. Notably the inclusion of a dusty stellar birth cloud component in the dust emission model provides more flexibility in accommodating the stellar population model, as its re-emission is highly sensitive to the ultraviolet radiation field spectrum and density. Binary populations favour a longer birth cloud dissipation time-scale than is found when assuming only single star population synthesis. [ABSTRACT FROM AUTHOR]

We present constraints on the physical properties (including stellar mass, age, and star formation rate) of 207 6 ≲ z ≲ 8 galaxy candidates from the Reionization Lensing Cluster Survey (RELICS) and Spitzer-RELICS surveys. We measure photometry using T-PHOT and perform spectral energy distribution fitting using EAzY and BAGPIPES. Of the 207 candidates for which we could successfully measure (or place limits on) Spitzer fluxes, 23 were demoted to likely z < 4. Among the high-z candidates, we find intrinsic stellar masses between 1 × 106M⊙ and 4 × 109M⊙, and rest-frame UV absolute magnitudes between −22.6 and −14.5 mag. While our sample is mostly comprised of galaxies, it extends to. Our sample spans ∼4 orders of magnitude in stellar mass and star formation rates, and exhibits ages that range from maximally young to maximally old. We highlight 11 z ≥ 6.5 galaxies with detections in Spitzer/IRAC imaging, several of which show evidence for some combination of evolved stellar populations, large contributions of nebular emission lines, and/or dust. Among these is PLCKG287+32-2013, one of the brightest z ∼ 7 candidates known (AB mag 24.9 at 1.6 μm) with a Spitzer 3.6 μm flux excess suggesting strong [O iii ] + H-β emission (∼1000 Å rest-frame equivalent width). We discuss the possible uses and limits of our sample and present a public catalog of Hubble + Spitzer photometry along with physical property estimates for all objects in the sample. Because of their apparent brightnesses, high redshifts, and variety of stellar populations, these objects are excellent targets for follow-up with the James Webb Space Telescope. [ABSTRACT FROM AUTHOR]