Soft X-ray transmission spectroscopy of a warm/hot intergalactic medium with XEUS

Abstract

We discuss the detectability of a Warm/Hot Intergalactic Medium (WHIM) via absorption lines toward bright point sources with a future X-ray satellite mission, XEUS. While we consider bright QSOs as specific examples, the methodology can be applied to bright gamma-ray burst afterglows. We created mock absorption spectra for bright QSOs (more than 20 QSOs over all sky) using the light-cone output of a cosmological hydrodynamic simulation. We assumed that the WHIM is under collisional and photo-ionization equilibrium. If WHIM has a constant metallicity of Z = 0.1 Z⊙, approximately 2 O VII absorption line systems with > 3 σ will be detected on average along a random line-of-sight toward bright QSOs up to z = 0.3 for a 30 ks exposure. © 2006. Astronomical Society of Japan.