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A large fraction of accreting black hole and neutron stars systems present clear evidence of the reprocessing of X-rays in the atmosphere of an optically-thick accretion disk. The main hallmarks of X-ray reflection include fluorescent K-shell emission lines from iron ($sim 6.4-6.9$ keV), the absorption iron K-edge ($sim 7-9$ keV), and a broad featureless component known as the Compton hump ($sim 20-40$ keV). This Compton hump is produced as the result of the scattering of high-energy photons ($E gtrsim 10$ keV) of the relatively colder electrons ($T_e sim 10^5-10^7$ K) in the accretion disk, in combination with photoelectric absorption from iron. The treatment of this process in most current models of ionized X-ray reflection has been done using an approximated Gaussian redistribution kernel. This approach works sufficiently well up to $sim100$ keV, but it becomes largely inaccurate at higher energies and at relativistic temperatures ($T_esim10^9$ K). We present new calculations of X-ray reflection using a modified version of our code XILLVER, including an accurate solution for Compton scattering of the reflected unpolarized photons in the disk atmosphere. This solution takes into account quantum electrodynamic and relativistic effects allowing the correct treatment of high photon energies and electron temperatures. We show new reflection spectra computed with this model, and discuss the improvements achieved in the reproducing the correct shape of the Compton hump, the discrepancies with previous calculations, and the expected impact of these new models in the interpretation of observational data.
X-ray flux from the inner hot region around central compact object in a binary system illuminates the upper surface of an accretion disc and it behaves like a corona. This region can be photoionised by the illuminating radiation, thus can emit differ
Relativistic reflection features in the X-ray spectra of black hole binaries and AGNs are thought to be produced through illumination of a cold accretion disk by a hot corona. In this work, we assume that the corona has the shape of an infinitesimall
The X-ray spectra of the most extreme ultra-luminous X-ray sources -- those with L > 1 E+40 erg/s -- remain something of a mystery. Spectral roll-over in the 5-10 keV band was originally detected in in the deepest XMM-Newton observations of the brigh
We have calculated the relativistic reflection component of the X-ray spectra of accretion disks in active galactic nuclei (AGN). Our calculations have shown that the spectra can be significantly modified by the motion of the accretion flow and the g
Plasma accreted onto the surface of a neutron star can ignite due to unstable thermonuclear burning and produce a bright flash of X-ray emission called a Type-I X-ray burst. Such events are very common; thousands have been observed to date from over