We study the intrinsic large-scale distribution and evolution of seven ionized metals in the IllustrisTNG magnetohydrodynamical cosmological simulation. We focus on the fractions of C ii, C iv, Mg ii, N v, Ne viii, O vi, and Si iv in different cosmic web structures (filaments, haloes, and voids) and gas phases (warm–hot intergalactic medium, hot, diffuse, and condensed gas) from z = 6 to z = 0. Our analysis provides a new perspective to the study of the distribution and evolution of baryons across cosmic time while offering new hints in the context of the well-known missing baryons problem. The cosmic web components are here identified using the local comoving dark matter density, which provides a simple but effective way of mapping baryons on large scales. Our results show that C ii and Mg ii are mostly located in condensed gas inside haloes in high-density and low-temperature star-forming regions ($\rho _{\rm gas}/\bar{\rho }_{\rm bar}\gtrsim 10^3$, and T ≲ 105 K). C iv and Si iv present similar evolution of their mass fractions in haloes and filaments across cosmic time. In particular, their mass budgets in haloes in condensed phase ($\rho _{\rm gas}/\bar{\rho }_{\rm bar}\gtrsim 10^3$, and T ≲ 105 K) are driven by gas cooling and star formation with a peak at z ∼ 2. Finally, our results confirm that O vi, Ne viii, and N v are good tracers of warm/hot and low-density gas at low redshift ($\rho _{\rm gas}/\bar{\rho }_{\rm bar}\lesssim 10^3$, and T ≳ 105 K), regions that are likely to contain most of the missing baryons in the local Universe.
We introduce a new model of the evolution of the concentration of dark matter haloes, c(t). For individual haloes, our model approximates c(t) as a power law with a time-dependent index, such that at early times, concentration has a nearly constant value of c ≈ 3–4, and as cosmic time progresses, c(t) smoothly increases. Using large samples of halo merger trees taken from the Bolshoi–Planck and MultiDark Planck 2 cosmological simulations, we demonstrate that our three-parameter model can approximate the evolution of the concentration of individual haloes with a typical accuracy of 0.1 dex for $t\gtrsim 2\, {\rm Gyr}$ for all Bolshoi–Planck and MultiDark Planck 2 haloes of present-day peak mass $M_{0}\gtrsim 10^{11.5}\, {\rm M}_{\odot }$. We additionally present a new model of the evolution of the concentration of halo populations, which we show faithfully reproduces both average concentration growth and the diversity of smooth trajectories of c(t), including capturing correlations with halo mass and halo assembly history. Our publicly available source code, diffprof, can be used to generate Monte Carlo realizations of the concentration histories of cosmologically representative halo populations. diffprof is differentiable due to its implementation in the jax autodiff library, which facilitates the incorporation of our model into existing analytical halo model frameworks.
more » « less- NSF-PAR ID:
- 10466010
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Monthly Notices of the Royal Astronomical Society
- Volume:
- 526
- Issue:
- 1
- ISSN:
- 0035-8711
- Page Range / eLocation ID:
- p. 1528-1544
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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