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EPOCHS VII: Discovery of high redshift (6.5 < z < 12) AGN candidates in JWST ERO and PEARLS data Published: 7/14/2023 3:03:24 PM Updated: 7/18/2023 12:36:08 PM

Paper abstract: We present an analysis of a sample of robust high redshift galaxies selectedphotometrically from the `blank' fields of the Prime Extragalactic Areas forReionization Science (PEARLS) survey and Early Release Observations (ERO) dataof the James Webb Space Telescope (JWST) with the aim of selecting candidatehigh redshift active galactic nuclei (AGN). Sources were identified from theparent sample using a threefold selection procedure, which includes spectralenergy distribution (SED) fitting to identify sources that are best fitted byAGN SED templates, a further selection based on the relative performance of AGNand non-AGN models, and finally morphological fitting to identify compactsources of emission, resulting in a purity-oriented procedure. Using thisprocedure, we identify a sample of nine AGN candidates at 6.5 < z < 12, fromwhich we constrain their physical properties as well as measure a lower boundon the AGN fraction in this redshift range of 5 \pm 1\%. As this is anextreme lower limit due to our focus on purity and our SEDs being calibratedfor unobscured Type 1 AGN, this demonstrates that AGN are perhaps quite commonat this early epoch. The rest-frame UV colors of our candidate objects suggestthat these systems are potentially candidate obese black hole galaxies (OBG),or AGN with very little galaxy component. We also investigate emission from oursample sources from fields overlapping with Chandra and VLA surveys, allowingus to place X-ray and 3 GHz radio detection limits on our candidates. Of noteis a z = 11.9 candidate source exhibiting an abrupt morphological shift inthe reddest band as compared to the bluer bands, indicating a potential mergeror an unusually strong outflow.