# CEERS Key Paper VI: JWST/MIRI Uncovers a Large Population of Obscured AGN at High Redshifts

**Authors:** G. Yang, K. I. Caputi, C. Papovich, P. Arrabal Haro, M. B. Bagley, P. Behroozi, E. F. Bell, L. Bisigello, V. Buat, D. Burgarella, Y. Cheng, N. J. Cleri, R. Dave, M. Dickinson, D. Elbaz, H. C. Ferguson, S. L. Finkelstein, N. A. Grogin, N. P. Hathi, M. Hirschmann  
**arXiv:** [2303.11736](https://arxiv.org/abs/2303.11736)  
**Date:** 2023-03-21  
**Summary page:** https://www.summarizepaper.com/en/paper/2303.11736v1/

## Key points

- Study focuses on using mid-infrared observations to identify heavily obscured AGN in the distant universe
- Researchers utilize data from MIRI onboard JWST, specifically from CEERS
- Objects classified into three categories: star-forming galaxies (SF), SF-AGN mixed objects, and AGN
- Sample consists of 418 star-forming galaxies, 111 SF-AGN mixed objects, and 31 AGN
- Objects span a redshift range of approximately 0 to 5
- Median SEDs derived for each source type and publicly released
- Median MIRI SED of AGN similar to hot dust-obscured galaxies and Seyfert 2s, suggesting emissions predominantly from AGN-heated hot dust
- BHAD estimates compared with X-ray measurements; good agreement at redshifts below 3 but higher estimates at redshifts above 3 due to missed objects by X-ray surveys
- High-redshift BHAD estimates substantially higher than those derived from X-ray data by approximately one dex around redshifts 4 to 5
- MIRI's power in identifying heavily obscured AGN not detected by X-ray surveys at high redshifts highlighted
- Results contribute to understanding the AGN population and their growth over cosmic time.

## Summary

This study focuses on the use of mid-infrared observations to identify heavily obscured Active Galactic Nuclei (AGN) in the distant universe. The researchers utilize data from the Mid-Infrared Instrument (MIRI) onboard the James Webb Space Telescope (JWST), specifically from the Cosmic Evolution Early Release Science Survey (CEERS). By analyzing spectral energy distribution (SED) modeling, they classify MIRI-selected objects into three categories: star-forming galaxies (SF), SF-AGN mixed objects, and AGN. The sample consists of 418 star-forming galaxies, 111 SF-AGN mixed objects, and 31 AGN, obtained from four MIRI pointings covering approximately 9 square arcminutes. These objects span a redshift range of approximately 0 to 5. The researchers derive median SEDs for each source type and publicly release them. Interestingly, they find that the median MIRI SED of AGN is similar to the typical SEDs of hot dust-obscured galaxies and Seyfert 2s, suggesting that the mid-infrared emissions in these sources are predominantly from AGN-heated hot dust. Furthermore, based on their SED-fit results, the researchers estimate the black hole accretion density (BHAD), which represents the total black hole growth rate per comoving volume as a function of redshift. They compare their BHAD estimates with X-ray measurements and find good agreement at redshifts below 3. However, at higher redshifts (z > 3), they identify a total of 28 AGN and SF-AGN mixed objects that were missed by X-ray surveys. Consequently, their high-redshift BHAD estimates are substantially higher than those derived from X-ray data by approximately one dex at redshifts around 4 to 5. These findings highlight the power of MIRI in identifying a large population of heavily obscured AGN that are not detected by X-ray surveys at high redshifts. The results contribute to our understanding of the AGN population and their growth over cosmic time.