2018/10/31 by Davide Martizzi, Mark Vogelsberger, Maria Celeste Artale +9
Physics and Astronomy · #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stz1106
Accepted by MNRAS
arxiv created 2019/04/17 · arxiv updated 2019/05/01
We analyze the IllustrisTNG simulations to study the mass, volume fraction and phase distribution of gaseous baryons embedded in the knots, filaments, sheets and voids of the Cosmic Web from redshift z=8 to redshift z=0. We find that filaments host more star-forming gas than knots, and that filaments also have a higher relative mass fraction of gas in this phase than knots. We also show that the cool, diffuse Intergalactic Medium (IGM; T<105 \rm K, n\rm H<10-4(1+z) \rm cm-3) and the Warm-Hot Intergalactic Medium (WHIM; 105 \rm K <T<107 \rm K, n\rm H <10-4(1+z) \rm cm-3) constitute ∼ 39% and ∼ 46% of the baryons at redshift z=0, respectively. Our results indicate that the WHIM may constitute the largest reservoir of \it missing baryons at redshift z=0. Using our Cosmic Web classification, we predict the WHIM to be the dominant baryon mass contribution in filaments and knots at redshift z=0, but not in sheets and voids where the cool, diffuse IGM dominates. We also characterise the evolution of WHIM and IGM from redshift z=4 to redshift z=0, and find that the mass fraction of WHIM in filaments and knots evolves only by a factor ∼ 2 from redshift z=0 to z=1, but declines faster at higher redshift. The WHIM only occupies 4-11% of the volume at redshift 0≤ z ≤ 1. We predict the existence of a significant number of currently undetected OVII and NeIX absorption systems in cosmic filaments which could be detected by future X-ray telescopes like Athena.