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

Speaker：Jianwei Lyu (Steward Observatory, University of Arizona)

Time：2:00 pm April 02th (Tuesday)

Location: Lecture Hall, 3rd floor

Report in English

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.

CV：Jianwei Lyu is an assistant researcher professor at the Steward Observatory, University of Arizona and a member of JWST MIRI/NIRCam GTO science team. His major research area is the study of galaxy evolution with a focus on AGN/quasar.  Right now, he is leading several JWST GTO/GO projects ranging from the study of dust grains in the nearby starburst galaxies to the host galaxy properties of most distant quasars in the reionization age. He received his PhD degree in 2020 at the University of Arizona with Dr. George Rieke on the reconciliation of AGN IR properties from z~0 to z~6.