Securing the Detection of the Hot Roaming Baryons with the XMM-Newton

We propose a 1.6 Ms XMMNewton Very Large Program.. to settle unambiguouslyone of the most controversial and open problems of modern astrophysics: theexistence of the missing baryons in a WHIM. We will do so by complementing thefirst successful exploratory LETG observation of the z>0.4 blazar 1ESvirgul1553+113,with additional 1.6 Ms of XMMNewton RGS time, so more than doubling the S/N andthus the absorption line equivalent width sensitivity of the currently availableLETG spectrum in the fundamental spectral region of the intervening oxygen. Theproposed observation will enable:(1) the solution to the missingbaryon problem;(2) a robust estimate of the WHIM metallicity; (3) pioneering studiesof thermoand chemodynamics of the IGM with cosmic time and so of the diffusegas/galaxies interplay. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]