Caltech Postdoc Launch Seminar

Lunch will be served at 11:45 AM Please RSVP for lunch.

Dr. Wuji Wang

Discovery of Close Companions around Radio-Loud Active Galactic Nuclei 11.5 GyrAgo Using State-of-the-art Ground- and Space-based Observatories

Mergers are important in stellar mass buildup and triggering feedback especially in high-redshift universe. High-z radio galaxies (z>2, radio loud type-2 quasars) are known to trace dense protocluster environment and host by M_star~1011 galaxies. The view on 10s of kpc scales is elusive until recent high sensitivity observatories.  In this talk, I will present our joint ALMA+JWST/NIRSpec IFU view around the center of four z=3.5 radio AGN. We ubiquitously discover ~12 companion systems <18 kpc using two independent methods: (i) peculiar [OIII] kinematics; (ii) [CII] emissions. We estimate that these systems having M_dyn~109-11 which indicates minor merger scenario. ALL [CII] emitting blobs are detected offset from the AGN position suggesting that cold gas doesn't reside in the massive host. Out results indicates that these mergers could be the trigger of the most powerful AGN jet at the beginning of Cosmic Noon. They bring gas to the super massive black holes in the gas-poor host and ignite the AGN feedback. We also find that they can impact the propagation of the jet, e.g., deflecting the jet. Overall, they play important role in the evolution of the progenitor of massive galaxy clusters. Our new discover is an important guide for 10s of kpc scales galaxy evolution (galaxy-galaxy merger) in the early universe.

For more information, please contact Sejun Kim by email at [email protected] or visit this link to fill up the form and nominate yourself as a speaker.