We present a novel approach for identifying cosmic web filaments within the DISPERSE structure identification framework, using cosmic density field estimates from the Monte Carlo Physarum Machine (MCPM), inspired by the slime mold organism. We apply our method to the IllustrisTNG (TNG100) cosmological simulations and investigate the impact of filaments on galaxies. The MCPM density field is superior to the Delaunay tessellation field estimator in tracing the true underlying matter distribution and allows filaments to be identified with higher fidelity, finding more low-prominence/diffuse filaments. Using our new filament catalogs, we find that ≳90% of galaxies are located within ∼1.5 Mpc of a filamentary spine, with little change in the median star formation activity with distance to the nearest filament. Instead, we uncover a differential effect of the local filament line density, Σfil (MCPM)—the total MCPM overdensity per unit length along a filament segment—on galaxy formation: most galaxies are quenched and gas-poor near high-line density filaments at z ≤ 1. At earlier times, the filamentary environment appears to have no effect on galactic gas supply and quenching. At z = 0, quenching in log(M*/M⊙)≳10.5 galaxies is mainly driven by mass, while lower-mass galaxies are significantly affected by the filament line density. Satellites are far more susceptible to filaments than centrals. The local environments of massive halos are not sufficient to account for the effect of filament line density on gas removal and quenching. Our new approach holds great promise for observationally identifying filaments from galaxy surveys such as SDSS and DESI.
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The Evolving Effect of Cosmic Web Environment on Galaxy Quenching
Abstract We investigate how cosmic web structures affect galaxy quenching in the IllustrisTNG (TNG100) cosmological simulations by reconstructing the cosmic web within each snapshot using the D is P er SE framework. We measure the comoving distance from each galaxy with stellar mass log ( M * / M ⊙ ) ≥ 8 to the nearest node ( d node ) and the nearest filament spine ( d fil ) to study the dependence of both the median specific star formation rate (〈sSFR〉) and the median gas fraction (〈 f gas 〉) on these distances. We find that the 〈sSFR〉 of galaxies is only dependent on the cosmic web environment at z < 2, with the dependence increasing with time. At z ≤ 0.5, 8 ≤ log ( M * / M ⊙ ) < 9 galaxies are quenched at d node ≲ 1 Mpc, and have significantly suppressed star formation at d fil ≲ 1 Mpc, trends driven mostly by satellite galaxies. At z ≤ 1, in contrast to the monotonic drop in 〈sSFR〉 of log ( M * / M ⊙ ) < 10 galaxies with decreasing d node and d fil , log ( M * / M ⊙ ) ≥ 10 galaxies—both centrals and satellites—experience an upturn in 〈sSFR〉 at d node ≲ 0.2 Mpc. Much of this cosmic web dependence of star formation activity can be explained by an evolution in 〈 f gas 〉. Our results suggest that in the past ∼10 Gyr, low-mass satellites are quenched by rapid gas stripping in dense environments near nodes and gradual gas starvation in intermediate-density environments near filaments. At earlier times, cosmic web structures efficiently channeled cold gas into most galaxies. State-of-the-art ongoing spectroscopic surveys such as the Sloan Digital Sky Survey and DESI, as well as those planned with the Subaru Prime Focus Spectrograph, JWST, and Roman, are required to test our predictions against observations.
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- Award ID(s):
- 2137452
- PAR ID:
- 10457375
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 950
- Issue:
- 2
- ISSN:
- 0004-637X
- Page Range / eLocation ID:
- 114
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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