Speaker
Description
Active galactic nuclei (AGN) are pivotal drivers of galaxy evolution, yet many remain undetected in ultraviolet and optical surveys due to heavy dust obscuration. Tracking the AGN infrared (IR) contribution and number fraction (AGN fraction of IR-selected galaxies) provides insight into the dominance of AGN activity within galaxies and how common AGNs are across cosmic time. In these systems, dust absorbs the high-energy accretion disk emission and re-radiates it at longer wavelengths, making mid-IR observations essential for uncovering the full population of obscured AGN. Historically, the AKARI space telescope provided key insights into these populations; however, JWST’s 6.5m mirror offers ∼90 times the sensitivity of AKARI’s 0.68m aperture, allowing for the detection of much fainter objects during early stages of galaxy growth. Utilizing the JWST Systematic Mid-infrared Instrument Legacy Extragalactic Survey (SMILES) and the JWST Advanced Deep Extragalactic Survey (JADES), we leverage continuous optical to mid-IR coverage (5–25 μm) in the GOODS-S field to identify obscured AGN via multi- wavelength SED fitting with CIGALE. Our sample includes 278 AGN across 0 < z < 6, a seven-fold increase over previous JWST Cosmic Evolution Early Release Science (CEERS) survey studies due to the larger 15-pointing SMILES MIRI footprint. We find that both the AGN IR contribution and number fraction increase significantly with redshift, while decreasing as a function of total IR luminosity. This suggests that at higher redshifts, the IR galaxy luminosity is dominated by AGN activity and is primarily driven by abundant gas reservoirs and frequent mergers in the early universe, whereas in the local universe, high IR luminosity is increasingly dominated by intense starburst activity rather than black hole accretion. These results highlight JWST’s capacity to reveal previously hidden populations, suggesting that AGN activity was more prevalent and energetically dominant in the early universe.
| Participate the oral/poster presentation award competition | Yes |
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