‘Evolutionary’ Theories of the X-Ray Background

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چکیده ندارد.

The X–ray Background: Observations

The X-ray Background and the Deep X-ray Surveys

The deep X-ray surveys performed by the two major X-ray observatories on flight, Chandra and XMM, are being resolving the bulk of the cosmic X-ray background (XRB) in the 2–10 keV energy band, where the sky flux is dominated by extragalactic emission. Although the actual fraction depends on the absolute sky flux, which is measured with an uncertainty of ∼ 40%, most of the XRB is already resolve...

X-Ray Background Fluctuations

Minor Ha activity, consisting of small brightenings and small, surgelike spikes, was observed to take place above an active center at the solar limb in good time-association with small fluctuations in the soft X-ray background flux, suggesting that even small dynamical events seen optically are associated with coronal heating. The ratio of Ha flux to soft X-ray flux in some of the surges was ap...

The Sources of the X–ray Background

Deep X–ray surveys have shown that the cosmic X–ray background (XRB) is largely due to the accretion onto su-permassive black holes, integrated over cosmic time. The ROSAT, Chandra and XMM–Newton satellites have resolved more than 80% of the 0.1–10 keV X–ray background into discrete sources. Optical spectroscopic identifications are about 90% and 60% complete, for the deepest ROSAT and Chandra/...