Speaker: Nicole Sanchez (University of Washington)
Connecting Cosmic Gas Flows and Metal Enrichment to Supermassive Black Hole Growth in Galactic Evolution
"In this talk, I will discuss the impact of supermassive black hole (SMBH) feedback on the gas phase evolution of Milky Way-mass (MW-mass) galaxies. Both my simulation suites were created with the N-body+Smoothed particle hydrodynamics code, ChaNGa, and include a 25Mpc cosmological volume, Romulus25, and a suite of "genetically modified" (GM) galaxies. These GM galaxies originate from nearly identical initial conditions resulting in minor modifications to their accretion histories that maintain the large scale structure and final main halo mass of the original simulation. Exploring the MW-mass galaxies from these combined simulation suites, we find that (1) the SMBH propagates metals from the disk out into CGM,(2) how much metal is retained in the ISM (and CGM) depends on the SMBH's deviation from the M-sigma relation, and (3) black hole accretion histories can be influenced by larger-scale galaxy accretion physics, which work in tandem to quench star formation."
Speaker: Shivam Pandey (UPenn)
Cross-correlation of DES Y3 lensing and ACT/Planck thermal Sunyaev Zel’dovich Effect
Hot, ionized gas leaves an imprint on the cosmic microwave background via the thermal Sunyaev Zel’dovich (tSZ) effect. The cross-correlation of gravitational lensing (which traces the projected mass) with the tSZ effect (which traces the projected gas pressure) is a powerful probe of the thermal state of ionized baryons throughout the Universe, and is sensitive to effects such as baryonic feedback. I will present tomographic measurements and validation tests of the cross-correlation between galaxy shear measurements from the first three years of observations of the Dark Energy Survey, and tSZ measurements from a combination of Atacama Cosmology Telescope and Planck observations. I will describe how we use the same measurements to constrain models for the pressure profiles of halos across a wide range of halo mass and redshift. We find evidence for reduced pressure in low mass halos, consistent with predictions for the effects of feedback from active galactic nuclei. We infer the hydrostatic mass bias (B) from our measurements, finding a large value when adopting the Planck-preferred cosmological parameters. We additionally find hints of redshift evolution of B, which can help explain the large mass bias needed to reconcile cluster count measurements with the Planck-preferred cosmology. Our analysis introduces a model for the impact of intrinsic alignments (IA) of galaxy shapes on the shear-tSZ correlation for the first time. We show that IA can have a significant impact on these correlations at current noise levels.