CTC Seminar for 2024-01-31

Series: CTC Seminar
Date: Wednesday 31-Jan-2024
Time: 11:30-12:30 pm
Location: PSC 1136
Speaker: Namrata Roy (Johns Hopkins University)
Title: Violent feedback-driven winds from high z Radio loud AGNs revealed by JWST

Abstract: Active galactic nuclei (AGN) feedback via radio jets play a dominant role in shaping massive galaxies across cosmic time. Despite the relatively short lifetime of a powerful jet (~ 10^7 yr), its enormous energy output can significantly impact the host galaxy. These jets can trigger shocks and also drive large-scale gas outflows through an expanding over-pressured cocoon. High redshift radio galaxies (HzRGs) are particularly interesting since they host the most extreme examples with powerful outflows. However, spatially resolving these ionized outflows in sub-kpc scale is extremely challenging for HzRGs. In this talk, I will show how JWST is starting to make groundbreaking progress in feedback studies by pushing resolved optical-IR observations towards higher redshift, with better sensitivity, greater angular resolution over a large wavelength window. I will present NIRSpec IFU observations of two fascinating HzRGs (z~4), which show radio lobes and large scale outflow signatures. One object shows a clear one-sided conical shaped ionized emission, with high gas velocities (exceeding 900 km/s) and extremely broad line profiles (line width ~ 1200 km/s). The outflowing ionized nebulae spatially overlaps with the brighter radio lobe, indicating that the extraordinary gas kinematics are driven by the radio jets. The second source, on the other hand, shows a very clumpy ionized gas morphology, with several distinct velocity components extending on both sides of the central AGN core. Our analyses show that the regions with the broadest line profiles exhibits the strongest mass outflow rates in these radio-AGN systems, with their integrated outflow rates exceeding most luminous quasars across redshifts. Our work is just beginning to scrape the surface of the HzRGs and their jet-ISM interplay. More such examples will help us to place these observations in the context of low redshift well-studied sample from the nearby universe.

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