25–27 Mar 2026
Asia/Taipei timezone

Tracing AGN Contribution and Number Fraction Across Cosmic Time with JWST

25 Mar 2026, 14:20
3m
Astronomy and Astrophysics Poster Talks

Speaker

Angel Rodriguez Barbosa (National Tsing Hua University)

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. In these systems, dust absorbs the high-energy accretion disk emission and re-radiates it at longer wavelengths, making mid-infrared (IR) observations essential for uncovering the full population of obscured AGN. Tracking the AGN IR contribution and number fraction provides insight into the dominance of AGN activity within galaxies and how common AGNs are across cosmic time. Historically, the AKARI space telescope provided key insights into these populations; however, JWST’s 6.5m mirror offers $\sim$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 (0.4–25.5 $\mu$m) in the GOODS-S field to identify obscured AGN via multi-wavelength SED fitting with CIGALE. Our sample includes 290 AGN across 0 $<$ z $<$ 10.5, 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. 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.

Author

Angel Rodriguez Barbosa (National Tsing Hua University)

Co-author

Dr Tomotsugu Goto (National Tsing Hua University)

Presentation materials