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B. McKernan, C. S. Reynolds (University of Maryland College Park), T. Yaqoob (Johns Hopkins University)
Around half of the baryonic matter in the universe is expected to live in low density, high temperature filaments stretching between galaxies. This 'missing' matter (or warm/hot intergalactic medium) is so hot that it was not detected prior to the present generation of high resolution UV and X-ray telescopes. In X-rays, hot absorbing gas has been detected in the vicinity of the Galaxy and along the sight lines towards X-ray bright AGN. The local gas can be associated with the hot phase of a local filament of IGM (at z=0). The extragalactic gas can be associated with the hot phase of filaments between us and the X-ray bright AGN. We discuss X-ray detections of the hot phase of the IGM, around our Galaxy (at z=0) and beyond (at z>0). We review the observations and show that that the local hot gas can have multiple identities, including a local IGM filament and we show that there is considerable ambiguity in X-ray detections of extragalactic IGM. The hot missing matter at z>0 may still be missing.
We acknowledge funding support from NSF and NASA.
The author(s) of this abstract have provided an email address for comments about the abstract: mckernan@astro.umd.edu
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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.