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Recent studies have shown that galaxies at cosmic noon are redder in the center and bluer in the outskirts, mirroring results in the local universe. These color gradients could be caused by gradients in either the stellar age or dust opacity; however, distinguishing between these two causes is impossible with rest-frame optical photometry alone. Here we investigate the underlying causes of the gradients from spatially resolved rest-frame U - V versus V - J color-color diagrams measured from early observations with the James Webb Space Telescope. We use 1-4 mu m NIRCam photometry from the CEERS survey of a sample of 54 galaxies with log M-* /M-circle dot > 10 at redshifts 1.7 < z < 2.3 selected from the 3D-HST catalog. We model the light profiles in the F115W, F200W, and F356W NIRCam bands using imcascade, a Bayesian implementation of the multi-Gaussian expansion technique that flexibly represents galaxy profiles using a series of Gaussians. We construct resolved rest-frame U - V and V - J color profiles. The majority of star-forming galaxies have negative gradients (i.e., redder in the center, bluer in the outskirts) in both U - V and V - J colors consistent with radially decreasing dust attenuation. A smaller population (roughly 15%) of star-forming galaxies have positive U - V but negative V - J gradients implying centrally concentrated star formation. For quiescent galaxies, we find a diversity of UVJ color profiles, with roughly one-third showing star formation in their center. This study showcases the potential of JWST to study the resolved stellar populations of galaxies at cosmic noon.

One of the most fundamental baryonic matter components of galaxies is the neutral atomic hydrogen (H I). At low redshifts, this component can be traced directly through the 21 cm transition, but to infer the H I gas content of the most distant galaxies, a viable tracer is needed. We here investigate the fidelity of the fine-structure transition of the (P-2(3/2) - P-2(1/3)) transition of singly ionized carbon C II at 158 mu m as a proxy for H I in a set simulated galaxies at z approximate to 6, following the work by Heintz et al. We select 11,125 star-forming galaxies from the SIMBA simulations, with far-infrared line emissions postprocessed and modeled within the SIGAME framework. We find a strong connection between C II and H I, with the relation between this C I relation (beta([C II])) being anticorrelated with the gas-phase metallicity of the simulated galaxies. We further use these simulations to make predictions for the total baryonic matter content of galaxies at z approximate to 6, and specifically the H I gas mass fraction. We find mean values of M-H I/M-* = 1.4 and M-H I/ M-bar,M-tot = 0.45. These results provide strong evidence for H I being the dominant baryonic matter component by mass in galaxies at z approximate to 6.

We present the first spatially resolved measurements of galaxy properties in the JWST ERO SMACS0723 field. We perform a comprehensive analysis of five $5

With just a month of data, JWST is already transforming our view of the Universe, revealing and resolving starlight in unprecedented populations of galaxies. Although ``HST-dark" galaxies have previously been detected at long wavelengths, these observations generally suffer from a lack of spatial resolution which limits our ability to characterize their sizes and morphologies. Here we report on a first view of starlight from a subset of the HST-dark population that are bright with JWST/NIRCam (4.4$\mu$m<24.5mag) and very faint or even invisible with HST ($<$1.6$\mu$m). In this Letter we focus on a dramatic and unanticipated population of physically extended galaxies ($\gtrsim$0.17''). These 12 galaxies have photometric redshifts $2

We report the archival discovery of Ly alpha emission from the bright ultraviolet galaxy Y002 at z = 7.677, spectroscopically confirmed by its ionized carbon [C II] 158 mu m emission line. The Ly alpha line is spatially associated with the rest-frame UV stellar emission (M-UV similar to-22, 2x brighter than M-UV*), and it appears offset from the peak of the extended [C II] emission at the current similar to 1 '' spatial resolution. We derive an estimate of the unobscured SFRUV = (22 +/- 1) M-circle dot yr(-1) and set an upper limit of SFRIR < 15 M-circle dot yr(-1) from the far-infrared (FIR) wavelength range, which globally places Y002 on the SFR(UV-FIR)-L-[C II] correlation observed at lower redshifts. In terms of velocity, the peak of the Ly alpha emission is redshifted by Delta nu(Ly alpha) similar to 500 km s(-1) from the systemic redshift set by [C II] and a high-velocity tail extends up to similar to 1000 km s(-1). The velocity offset is up to similar to 3.5x higher than the average estimate for similarly UV-bright emitters at z similar to 6-7, which might suggest that we are witnessing the merging of two clumps. A combination of strong outflows and the possible presence of an extended ionized bubble surrounding Y002 would likely facilitate the escape of copious Ly alpha light, as indicated by the large equivalent width EW0(Ly alpha) = 24(-6)(+5) angstrom. Assuming that [C II] traces the neutral hydrogen, we estimate a H I gas fraction of M-H I/M* greater than or similar to 8 for Y002 as a system and speculate that patches of high H I column densities could contribute to explaining the observed spatial offsets between Ly alpha- and [C II]-emitting regions. The low dust content, implied by the nondetection of the FIR continuum emission at rest frame similar to 160 mu m, would be sufficient to absorb any potential Ly alpha photons produced within the [C II] clump as a result of large H I column densities.

We present the localization and host galaxies of one repeating and two apparently nonrepeating fast radio bursts (FRBs). FRB 20180301A was detected and localized with the Karl G. Jansky Very Large Array to a star-forming galaxy at z = 0.3304. FRB20191228A and FRB20200906A were detected and localized by the Australian Square Kilometre Array Pathfinder to host galaxies at z = 0.2430 and z = 0.3688, respectively. We combine these with 13 other well-localized FRBs in the literature, and analyze the host galaxy properties. We find no significant differences in the host properties of repeating and apparently nonrepeating FRBs. FRB hosts are moderately star forming, with masses slightly offset from the star-forming main sequence. Star formation and low-ionization nuclear emission-line region emission are major sources of ionization in FRB host galaxies, with the former dominant in repeating FRB hosts. FRB hosts do not track stellar mass and star formation as seen in field galaxies (more than 95% confidence). FRBs are rare in massive red galaxies, suggesting that progenitor formation channels are not solely dominated by delayed channels which lag star formation by gigayears. The global properties of FRB hosts are indistinguishable from core-collapse supernovae and short gamma-ray bursts hosts, and the spatial offset (from galaxy centers) of FRBs is mostly inconsistent with that of the Galactic neutron star population (95% confidence). The spatial offsets of FRBs (normalized to the galaxy effective radius) also differ from those of globular clusters in late- and early-type galaxies with 95% confidence.