Description
Filaments account for nearly half of the mass budget of the Universe and play an important role in shaping galaxy properties, such as star formation, metallicities, multi-phase gas properties, as well as the spins and orbits of galaxies. However, in observations we are typically constrained to study filaments traced by galaxies. How are these different from gas and dark matter filaments, and what are their different roles in impacting galaxy growth?
In this study, we utilize the TNG50-1 simulation to construct filament catalogues with the DisPerSE algorithm, based on the galaxy, dark matter, and gas density fields at z=0. We developed a matching scheme for three types of filament networks by fully exploring smoothing scales, calibrating persistence thresholds, and adjusting matching criteria. We find that only half of the filaments can be well-matched between the three fields, and matched filaments generally have higher mass density than the unmatched ones. This indicates that filaments traced by different tracers differ not only in their locations, but also in their properties. We investigate filament characteristics, including filament lengths, widths, masses, and their radial density profiles near nodes, saddles, and in between. We find that gas radial profiles are more extended than those of dark matter, with notable variations across three different regions. We also study how the properties of galaxy filaments vary with galaxy tracers of different masses. Our results show that shorter and more tenuous filaments are usually traced by lower-mass galaxies, which reveals a correlation between filament characteristics and galaxy properties.
