X-ray Source Counts and the X-ray Background from Uhuru

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چکیده ندارد.

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 X–ray Background: Observations

Hard X-Ray Emission from Elliptical Galaxies and Its Contribution to the X-Ray Background.

We explore the implications of the discovery of hard, power-law X-ray sources in the spectra of nearby elliptical galaxies for the origin of the X-ray background (XRB). The spectra of these sources are consistent with models of thermal bremsstrahlung emission from low radiative efficiency accretion flows around central supermassive black holes and are unique in that they approximately match the...