Measured cosmological mass density in the WHIM: The solution to the ‘Missing Baryons’ problem

Abstract

Abstract We review the current high-significance X-ray detections of Warm–Hot Intergalactic Medium (WHIM) filaments at z > 0 along the lines of sight to the two blazars Mrk 421 (z = 0.03) and 1ES 1028 + 511 (z = 0.361). For these WHIM filaments, we derive ionization corrections and, when possible, metallicity estimates. This allows us to obtain refined estimates of the number density of O VII WHIM systems down to the O VII column density sensitivity of our observations, and most importantly, a measurement of the cosmological mass density Ω b WHIM in the WHIM, at redshift z