Lunch talk on Feb. 26, 2024

AGN selection and demographics: a new age with JWST/MIRI

Speaker: Jianwei Lyu (University of Arizona)

Venue: SWIFAR Building 2111

Time: 12:30 PM, Monday, Feb. 26, 2024

Abstract: 

Completing the census of active galactic nuclei (AGN) activity is the key to study the build-up of supermassive black holes (SMBHs) and understand their relations with the host galaxy properties. Nevertheless, many AGNs are obscured by dust and gas, making the identification of such systems a challenging task even today. In this talk, I will present the first results on the AGN identifications across a wide range of redshift, luminosity, obscuration level and host galaxy properties based on the Systematic Mid-infrared Instrument Legacy Extragalactic Survey (SMILES). By combining the HST and JWST/NIRCam data at shorter wavelengths, we have identified 217 MIRI-detected AGNs over a survey area of ~34 arcmin^2. Despite the extensive pre-JWST efforts of AGN search with the deepest panchromatic data from the X-ray to the radio for the same filed, about 85% of our MIRI AGNs are newly found, demonstrating the unique power of JWST. The MIRI AGN sample includes 111 AGNs in normal massive galaxies at z=0-4, 86 AGN candidates in low-mass galaxies and a high-z sample of 20 AGN candidates at z=4-8.4, where the latter two populations poorly charted in the past. I will talk about what lessons have been learned and some ongoing follow-up studies on this topic.