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Abstract We investigate the properties of voids and void galaxies in theTNG300simulation. Using a luminous galaxy catalog and a spherical void-finding algorithm, we identify 5078 voids at redshiftz= 0. The voids cover 83% of the simulation volume and have a median radius of 4.4h−1Mpc. We identify two populations of field galaxies based on whether the galaxies reside within a void (“void galaxies”; 75,220 objects) or outside a void (“nonvoid galaxies”; 527,454 objects). Within the voids, mass does not directly trace light. Instead, the mean radial underdensity profile as defined by the locations of void galaxies is systematically lower than the mean radial underdensity profile as defined by the dark matter (i.e., the voids are more “devoid” of galaxies than they are of mass). Within the voids, the integrated underdensity profiles of the dark matter and the galaxies are independent of the local background density (i.e., voids-in-voids versus voids-in-clouds). Beyond the void radii, however, the integrated underdensity profiles of both the dark matter and the galaxies exhibit strong dependencies on the local background density. Compared to nonvoid galaxies, void galaxies are on average younger, less massive, bluer in color, less metal enriched, and have smaller radii. In addition, the specific star formation rates of void galaxies are ∼20% higher than nonvoid galaxies and, in the case of galaxies with central supermassive black holes withMBH≳ 3 × 106h−1M⊙, the fraction of active void galaxies is ∼25% higher than active nonvoid galaxies.
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This content will become publicly available on May 29, 2026
Density Profiles of TNG 300 Voids across Cosmic Time
Abstract We present radial density profiles, as traced by luminous galaxies and dark matter particles, for voids in 11 snapshots of theTNG 300simulation. The snapshots span 11.65 Gyr of cosmic time, corresponding to the redshift range 0 ≤z≤ 3. Using the comoving galaxy fields, voids were identified via a well-tested, watershed transformation-based algorithm. Voids were defined to be underdense regions that are unlikely to have arisen from Poisson noise, resulting in the selection of ∼100–200 of the largest underdense regions in each snapshot. At all redshifts, the radial density profiles as traced by both the galaxies and the dark matter resemble inverse top-hat functions. However, details of the functions (particularly the underdensities of the innermost regions and the overdensities of the ridges) evolve considerably more for the dark matter density profiles than for the galaxy density profiles. At all redshifts, a linear relationship between the galaxy and dark matter density profiles exists, and the slope of the relationship is similar to the bias estimates forTNG 300snapshots. Lastly, we identify distinct environments in which voids can exist, defining “void-in-void” and “void-in-cloud” populations (i.e., voids that reside in larger underdense or overdense regions, respectively), and we investigate ways in which the relative densities of dark matter and galaxies in the interiors and ridges of these structures vary as a function of void environment.
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- Award ID(s):
- 2009397
- PAR ID:
- 10629982
- Publisher / Repository:
- The Astrophysical Journal
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 985
- Issue:
- 2
- ISSN:
- 0004-637X
- Page Range / eLocation ID:
- 244
- Subject(s) / Keyword(s):
- Large-scale structure of the universe Voids Magnetohydrodynamical simulations
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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