Our Spotlight Series highlights recent advances in AGN science, with a strong emphasis on participation from early-career researchers, and includes plenty of time for community discussion following the presentations. 

Central Shocks and Metal-Enriched Outflows: A New View of AGN Feedback

Speaker

Peixin Zhu (Harvard University)

Abstract

The growth of galaxies and their central supermassive black holes (SMBHs) is tightly linked. However, the exact impact of active galactic nuclei (AGNs) feedback on the host galaxy is still uncertain, with different observations suggesting AGNs enhance, suppress, or do not affect the host galaxy star formation rate. Resolving these controversies requires proper treatment of shocks, which are known to exist with AGN-driven outflow and yet are difficult to distinguish from AGN emission. In my talk, I will present a new theoretical three-dimensional diagram built for integral-field spectroscopy that cleanly separates star formation, AGN, and shock-dominated spaxels. Furthermore, these separation results can be combined with theoretical diagnostics to map the spatial distribution of gas-phase metallicity, ionization parameter, and gas pressure within these galaxies. After applying this new technique to 8 nearby Seyfert galaxies, we reveal that AGN and star formation coexist in the galaxy center, and fast shocks are present at the base of AGN outflows in some galaxies. We also find that outflowing gas is systematically metal-enhanced relative to adjacent star-forming rings. I will discuss how these results refine the picture of AGN feedback and the implications for nuclear enrichment and gas transport.

Investigating AGN Feeding and Feedback Through Circumnuclear Gas Kinematics in NGC 3079 and NGC 1068

Speaker

Dr. Ming-Yi Lin (University of Toledo)

Abstract

Studying gas kinematics in the circumnuclear regions (< 100 pc) of nearby AGNs on spatial scales of <10 pc provides insights into gas transport toward the supermassive black hole (SMBH) and the impact of AGN feedback in both radiative and kinetic forms. The kinematics of cold molecular gas are observed with radio interferometers (ALMA and NOEMA), while the warm molecular gas in the near-IR are studied using adaptive optics (AO)-assisted integral field spectrographs (IFS; Keck/OSIRIS). In this talk, I will use NGC 1068 and NGC 3079, two nearby Compton-thick AGNs, as pilot targets to discuss two distinct types of molecular outflows located at distances of ~40 pc from the SMBH: a cooling-efficient, momentum-driven outflow and a cooling-inefficient, energy-driven outflow. I will also present the discrepancy between Bondi accretion prescriptions and observationally constrained mass accretion rates.

Seminar Connection

Zoom Registration, you will receive connection details by email after registration: https://zoom.us/j/97689874465?pwd=XZNUqr19oopa1LfD7hgln1aQ2vbnT2.1