Identifying and Distinguishing Quenching Galaxies with Spatially Resolved Star Formation in TNG50
Year: 2026
Type: article
Abstract: Using the TNG50 simulation, we determine observationally motivated metrics that can distinguish quenching galaxies from star-forming galaxies for M * ≥ 10 9.5 M ⊙ , based on the spatial distribution of their stellar populations. Quenching galaxies are not fully quenched but have low levels of ongoing star formation that decreases over time. The morphological metrics consider the concentration of star formation, size of the star-forming disk, and characteristic radii that trace sharp truncations of star formation. These metrics can separate simulated quenching galaxies based on morphology into populations where star formation is suppressed inside-out and outside-in. Inside-out quenched galaxies are more likely to be the most massive galaxy within their halo in the field, while outside-in quenched galaxies are satellites residing in dense environments and begin quenching ∼1 Gyr after being accreted. Outside-in quenched galaxies typically take ∼1.5 Gyr to quench, and inside-out quenched galaxies can take up to ∼3.5 Gyr, where the duration of quenching is a function of stellar mass. We find that each population of quenched galaxy experiences evolution of their morphological metrics, where the different quenched populations reside in unique locations in parameter space. Galaxies in the later stages of quenching are more easily distinguished than those in the early stages, when compared to star-forming galaxies. In addition, inside-out quenched galaxies can be distinguished compared to outside-in quenched galaxies, and the progress through the quenching episode can be estimated for both populations. These results have broad implications for distinguishing quenching galaxies in large galaxy surveys.
Source: The Astrophysical Journal
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Funders: National Science Foundation, National Aeronautics and Space Administration, Canadian Foundation for AIDS Research, Nuclear Safety and Security Commission, Alliance de recherche numérique du Canada, Gauss Centre for Supercomputing, Canadian Space Agency, Natural Sciences and Engineering Research Council of Canada, Science and Technology Facilities Council, Astrophysics Division
Awards: G1282217913, Witnessing the assembly of massive dark matter structures in the Universe and their impact on galaxy evolution, G3272986329, Astrophysics at the University of Birmingham - Consolidated grant 2022-2025, Collaborative Research: GOing GREEN at High Resolution - Spatially Deconstructing Environmental Quenching over 9 Billion Years, Collaborative Research: Tracing Galaxy Quenching in the Cosmic Web With Spatially-Resolved Star-Formation Maps, G7449009116, G814497173
OpenAlex ID: W7133352010
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