2000/07/15 by Romeel Davé, Renyue Cen, Jeremiah P. Ostriker +6 · 3 citations
Physics and Astronomy · #astro-ph
paper · pdf · doi:10.1086/320548
published as Astrophys.J.552:473-483,2001 · 9 pages, emulateapj, submitted to ApJ
arxiv created 2000/07/15 · arxiv updated 2016/08/15
Approximately 30-40% of all baryons in the present day universe reside in a warm-hot intergalactic medium (WHIM), with temperatures between 105<T<107 K. This is a generic prediction from six hydrodynamic simulations of currently favored structure formation models having a wide variety of numerical methods, input physics, volumes, and spatial resolutions. Most of these warm-hot baryons reside in diffuse large-scale structures with a median overdensity around 10-30, not in virialized objects such as galaxy groups or galactic halos. The evolution of the WHIM is primarily driven by shock heating from gravitational perturbations breaking on mildly nonlinear, non-equilibrium structures such as filaments. Supernova feedback energy and radiative cooling play lesser roles in its evolution. WHIM gas is consistent with observations of the 0.25 keV X-ray background without being significantly heated by non-gravitational processes because the emitting gas is very diffuse. Our results confirm and extend previous work by Cen & Ostriker and Dave' et al.