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Abstract The circumgalactic medium (CGM) around massive galaxies plays a crucial role in regulating star formation and feedback. Using the Cosmology and Astrophysics with MachinE Learning Simulations (CAMELS) suite, we develop emulators for the X-ray surface brightness profile and the X-ray luminosity–stellar mass scaling relation, to investigate how stellar and active galactic nucleus (AGN) feedback shape the X-ray properties of the hot CGM. Our analysis shows that at CGM scales (1012≲Mhalo/M⊙≲ 1013, 10 ≲rkpc−1≲ 400), stellar feedback more significantly impacts the X-ray properties than AGN feedback within the parameters studied. Comparing the emulators to recent eROSITA All Sky Survey (eRASS) observations, it is found that stronger feedback than is currently implemented in the IllustrisTNG, SIMBA, and Astrid simulations is required to match the observed CGM properties. However, adopting these enhanced feedback parameters causes deviations in the stellar mass–halo mass relations from observational constraints below the group-mass scale. This tension suggests possible unaccounted-for systematics in X-ray CGM observations or inadequacies in the feedback models of cosmological simulations.
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This content will become publicly available on October 23, 2026
Star Formation Rates, Metallicities, and Stellar Masses on Kiloparsec Scales in TNG50
Abstract Integral field units have extended our knowledge of galactic properties to kiloparsec (or, sometimes, even smaller) patches of galaxies. These scales are where the physics driving galaxy evolution (feedback, chemical enrichment, etc.) take place. Quantifying the spatially resolved properties of galaxies, both observationally and theoretically, is therefore critical to our understanding of galaxy evolution. To this end, we investigate spatially resolved scaling relations within galaxies ofM⋆ > 109.0atz= 0 in IllustrisTNG. We examine both the resolved star formation main sequence (rSFMS) and the resolved mass–metallicity relation (rMZR) using 1 kpc × 1 kpc maps. We find that the rSFMS in IllustrisTNG is well described by a power law but is significantly shallower than the observed rSFMS. However, the disagreement between the rSFMS of IllustrisTNG and observations is likely driven by an overestimation of AGN feedback in IllustrisTNG for the higher-mass hosts. Conversely, the rMZR for IllustrisTNG has very good agreement with observations. Furthermore, we argue that the rSFMS is an indirect result of the Schmidt–Kennicutt law and local gas relation, which are both independent of host galaxy properties. Finally, we expand upon a localized leaky-box model to study the evolution of idealized spaxels and find that it provides a good description of these resolved relations. The degree of agreement, however, between idealized spaxels and simulated spaxels depends on the “net” outflow rate for the spaxel, and the IllustrisTNG scaling relations indicate a preference for a low net outflow rate.
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- PAR ID:
- 10645070
- Publisher / Repository:
- The Astrophysical Journal
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 993
- Issue:
- 1
- ISSN:
- 0004-637X
- Page Range / eLocation ID:
- 32
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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