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EPOCHS VII: discovery of high-redshift (6.5 (6.5 < z <12) AGN candidates in JWST ERO and PEARLS data

Juodžbalis, I, Conselice, CJ, Singh, M, Adams, N, Ormerod, K, Harvey, T, Austin, D, Volonteri, M, Cohen, SH, Jansen, RA, Summers, J, Windhorst, RA, D’Silva, JCJ, Koekemoer, AM, Coe, D, Driver, SP, Frye, B, Grogin, NA, Marshall, MA, Nonino, M , Pirzkal, N, Robotham, A, Ryan Jr, RE, Ortiz III, R, Tompkins, S, Willmer, CNA and Yan, H (2023) EPOCHS VII: discovery of high-redshift (6.5 (6.5 < z <12) AGN candidates in JWST ERO and PEARLS data. Monthly Notices of the Royal Astronomical Society, 525 (1). pp. 1353-1364. ISSN 0035-8711

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Abstract

We present an analysis of a sample of robust high-redshift galaxies selected from the ‘blank’ fields of the Prime Extragalactic Areas for Reionization Science (PEARLS) survey and Early Release Observations (ERO) data from JWST with the aim of selecting candidate high-redshift active galactic nuclei (AGN). Sources were identified from this parent sample using a threefold selection procedure, which includes spectral energy distribution (SED) fitting to identify sources that are best fitted by AGN SED templates, a further selection based on the relative performance of AGN and non-AGN models, and finally morphological fitting to identify compact sources of emission, resulting in a purity-oriented procedure. Using this procedure, we identify a sample of nine AGN candidates at 6.5 < z < 12, from which we constrain their physical properties as well as measure a lower bound on the AGN fraction in this redshift range of 5 ± 1 per cent. As this is an extreme lower limit due to our focus on purity and our SEDs being calibrated for unobscured Type 1 AGN, this demonstrates that AGN are perhaps quite common at this early epoch. The rest-frame UV colours of our candidate objects suggest that these systems are potentially candidate obese black hole galaxies (OBGs). We also investigate Chandra and VLA maps of these areas from which we calculate detection limits. Of note is a z = 11.9 candidate source exhibiting an abrupt morphological shift in the reddest band as compared to bluer bands, indicating a potential merger or an unusually strong outflow.

Item Type: Article
Uncontrolled Keywords: 0201 Astronomical and Space Sciences; Astronomy & Astrophysics
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press (OUP)
SWORD Depositor: A Symplectic
Date Deposited: 23 Sep 2024 16:29
Last Modified: 23 Sep 2024 16:30
DOI or ID number: 10.1093/mnras/stad2396
URI: https://researchonline.ljmu.ac.uk/id/eprint/24248
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