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Abstract The first wave of observations with JWST has revealed a striking overabundance of luminous galaxies at early times (z> 10) compared to models of galaxies calibrated to pre-JWST data. Early observations have also uncovered a large population of supermassive black holes (SMBHs) atz> 6. Because many of the high-zobjects appear extended, the contribution of active galactic nuclei (AGNs) to the total luminosity has been assumed to be negligible. In this work, we use a semi-empirical model for assigning AGNs to galaxies to show that active galaxies can boost the stellar luminosity function (LF) enough to solve the overabundance problem while simultaneously remaining consistent with the observed morphologies of high-zsources. We construct a model for the composite AGN+galaxy LF by connecting dark matter halo masses to galaxy and SMBH masses and luminosities, accounting for dispersion in the mapping between host galaxy and SMBH mass and luminosity. By calibrating the model parameters — which characterize the M_∙-M_*relation — to a compilation ofz> 10 JWST UVLF data, we show that AGN emission can account for the excess luminosity under a variety of scenarios, including one where 10% of galaxies host BHs of comparable luminosities to their stellar components. Using a sample of simulated objects and real observations, we demonstrate that such low-luminosity AGNs can be `hidden' in their host galaxies and be missed in common morphological analyses. We find that for this explanation to be viable, our model requires a population of BHs that are overmassive (M_∙/M_*~ 10^-2) with respect to their host galaxies compared to the local relation and are more consistent with the observed relation atz= 4-8. We explore the implications of this model for BH seed properties and comment on observational diagnostics necessary to further investigate this explanation. 

Undergraduate physics and astronomy students are expected to engage with scientific literature as they begin their research careers, yet reading comprehension skills are rarely explicitly taught in major courses. We seek to determine the efficacy of a reading assignment designed to improve undergraduate astronomy (or related) majors’ perceived ability to engage with research literature by using accessible summaries of current research written by experts in the field. During the 2022–2023 academic year, faculty members from six institutions incorporated reading assignments using accessible summaries from Astrobites into their undergraduate astronomy major courses, surveyed their students before and after the activities, and participated in follow-up interviews with our research team. Quantitative and qualitative survey data from 52 students show that students’ perceptions of their abilities to understand jargon and identify the main takeaways of a paper significantly improved with the use of the tested assignment template. Additionally, students reported increased confidence in their abilities within astronomy after exposure to these assignments, and instructors having valued a ready-to-use resource for incorporating reading comprehension into their pedagogy. This exploratory case study, using Astrobites-based assignments, suggests that incorporating current research into the undergraduate classroom through accessible literature summaries may increase students’ confidence and ability to engage with research literature, thereby assisting in their preparation for participation in research careers. 

ABSTRACT The formation of the first stars marks a watershed moment in the history of our Universe. As the first luminous structures, these stars (also known as Population III, or Pop III stars) seed the first galaxies and begin the process of reionization. We construct an analytic model to self-consistently trace the formation of Pop III stars inside minihaloes in the presence of the fluctuating ultraviolet background, relic dark matter (DM)-baryon relative velocities from the early universe, and an X-ray background, which largely work to suppress cooling of gas and delay the formation of this first generation of stars. We demonstrate the utility of this framework in a semi-analytic model for early star formation that also follows the transition between Pop III and Pop II star formation inside these haloes. Using our new prescription for the criteria allowing Pop III star formation, we follow a population of DM haloes from z = 50 through z = 6 and examine the global star formation history, finding that each process defines its own key epoch: (i) the stream velocity dominates at the highest redshifts (z ≳ 30), (ii) the UV background sets the tone at intermediate times (30 ≳ z ≳ 15), and (iii) X-rays control the end of Pop III star formation at the latest times (z ≲ 15). In all of our models, Pop III stars continue to form down to z ∼ 7–10, when their supernovae will be potentially observable with forthcoming instruments. Finally, we identify the signatures of variations in the Pop III physics in the global 21-cm spin–flip signal of atomic hydrogen.