Namrata Roy (Johns Hopkins University)
Turning a page in the AGN feedback chapter: A new era of spatially resolving outflows across cosmic time

Active Galactic Nuclei (AGN) driven feedback via jets and outflows play a dominant role in shaping galaxies across cosmic time. Recent results from JWST show an overabundance of AGN candidates especially at higher redshifts, which has deemed their role to be even more crucial in deciding the fate of galaxies. In this talk, I will first present one of the most violent and energetic ionized gas outflows around the radio lobes of a z>4 Radio Galaxy, spatially resolved with JWST/NIRSpec IFU at an exquisite detail. I will map the resolved gas outflow rate, energy and momentum to dissect how efficiently the radio jet-driven is transferring energy to the surroundings. I will next give a glimpse of low luminosity AGN (LLAGN) outflows hidden amidst normal star forming galaxies. I will present the spatially resolved ionized gas morphology ionization, and gas kinematics of a large sample of z ~ 1 galaxies to identify hidden outflow signatures and determine how the galaxy ISM properties evolve with redshift. Finally, I will end by briefly talking about a new exciting discovery where we found low luminosity AGN outflows in a new population of old, dead and quenched galaxies in the nearby universe (z < 0.1). Named “red geysers”. these may be the first direct evidence of feedback in action in passive galaxies with no star formation. While JWST are finding more such objects at higher redshift, this may be the beginning of establishing a connection between AGN feedback and star formation quenching in the massive galaxy population.

Caroline McCormick (University of Virginia)
An Investigation of Non-Canonical Mixing in Red Giant Stars Using APOGEE 12C/13C Ratios Observed in Open Cluster Stars

Standard stellar evolution theory poorly predicts the surface abundances of chemical species in low-mass, red giant branch (RGB) stars. Observations show an enhancement of p-p chain and CNO cycle products in red giant envelopes, which suggests the existence of non-canonical mixing that brings interior burning products to the surface of these stars. The 12C/13C ratio is a highly sensitive abundance metric used to probe this mixing. We investigate extra RGB mixing by examining (1) how 12C/13C is altered along the RGB and (2) how 12C/13C changes for stars of varying age and mass. Our sample consists of 43 red giants spread over 15 open clusters from the Sloan Digital Sky Survey's APOGEE DR17 that have reliable 12C/13C ratios derived from their APOGEE spectra. We vetted these 12C/13C ratios and compared them as a function of evolution and age/mass to the standard mixing model of stellar evolution and to a model that includes prescriptions for RGB thermohaline mixing and stellar rotation. We find that the observations deviate from standard mixing models, implying the need for extra mixing. Additionally, some of the abundance patterns depart from the thermohaline model, and it is unclear whether these differences are due to incomplete observations, issues inherent to the model, our assumption of the cause of extra mixing, or any combination of these factors. Nevertheless, the surface abundances across our age/mass range clearly deviate from the standard model, agreeing with the notion of a universal mechanism for RGB extra mixing in low-mass stars.