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Abstract The circumgalactic medium (CGM) is a reservoir of metals and star-forming fuel. Most baryons in the Universe are in the CGM or the intergalactic medium (IGM). The baryon cycle—how mass and metals reach the CGM from the inner regions of the galaxy and how gas from the CGM replenishes star-forming activity in the inner regions—is an essential question in galaxy evolution. In this paper, we study the flow of mass and metals in a stacked sample of 2770 isolated halos from the IllustrisTNG100 cosmological hydrodynamic simulation. The mean gas flow as a function of radius and angle is similar across a large galactic mass range when accounting for different feedback modes. Although both star formation and black holes cause powerful outflows, the flows from star formation are more angularly restricted. Black hole feedback dominates mass flow throughout the halo, while star formation feedback mainly affects the inner region. When scaling by virial radius (Rv), large dynamical changes occur at 0.2Rvfor most halos, suggesting a characteristic size for the inner galaxy. Despite kinetic-mode feedback from black holes being the primary quenching mechanism in IllustrisTNG, a small population of high-mass kinetic-mode disks are able to form stars.
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This content will become publicly available on February 28, 2026
Mass and Metal in Motion; The Gas Dynamics of IllustrisTNG Halos
The circumgalactic medium (CGM) is a known reservoir of metals and star forming fuel. Most baryons in the universe are in the CGM or ICM. The baryon cycle- how metals reach the CGM from the inner regions of the galaxy and how gas from the CGM replenishes star forming activity in the inner regions- is an essential question in galaxy evolution. We seek to illuminate these processes by analyzing 2770 isolated halos in the IllustrisTNG simulation. This sample is divided into different classes of galaxy based star forming and AGN feedback, and morphology. By stacking halos of similar mass and history, we can identify correlations between galaxy history and the properties and dynamics of the surrounding gas.
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- Award ID(s):
- 2007013
- PAR ID:
- 10656234
- Publisher / Repository:
- Bulletin of the American Astronomical Society
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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