A modification of the popular unification model for Seyfert galaxies is proposed, which takes into account recent observational findings on the statistical properties of both type 1 and type 2 Seyferts. In the proposed scenario, Compton–thick Seyfert 2 galaxies are those sources observed through compact, thick matter (the ‘torus’), while Compton–thin/ intermediate Seyfert galaxies are obscured ...

Using the Lagrangian that was developed on the corresponding principle between the moving medium electrodynamic and quantum field theory the explicit expression for the static polarizability vertex has been obtained. The applications of this vertex for calculations of real Compton scattering amplitude as well as the imaginary part of doubly virtual Compton scattering amplitude have been demonst...

Performance, resolution and spectral throughput both of the sagittally focusing monochromator and of the alternately installed two analysing systems, a Cauchois-type cylindrically bent crystal analyser for Compton-profile measurements, and a spherically bent crystal analyser for S(q, (^-measurements, of the new Compton spectrometer at the HARWI (harter Röntgen Wiggler) of the DORIS storage ring...

In radionuclide treatment, tumor cells are primarily destroyed by charged particles emitted by the compound while associated higher energy photons are used to image the tumor in order to determine radiation dose and monitor shrinkage. However, the higher energy photons are difficult to image with conventional collimated Anger cameras, since a tradeoff exists between resolution and sensitivity, ...

Observations with the IRS spectrograph onboard Spitzer have found many sources with very deep Si features at 9.7 μm, that have optical depths of τ > 1. Since it is believed that a few of these systems in the local Universe are associated with Compton-thick active galactic nuclei (hereafter AGN), we set out to investigate whether the presence of a strong Si absorption feature is a good indicator...

We present a detailed and self-consistent modeling of the cosmic X-ray background (XRB) based on the most up-todate X-ray luminosity functions (XLF) and evolution of Active Galactic Nuclei (AGN). The large body of observational results collected by soft (0.5-2 keV) and hard (2-10 keV) X-ray surveys are used to constrain at best the properties of the Compton-thin AGN population and its contribut...

In a number of papers an attractive method of laser polarization of electrons (positrons) at storage rings or linear colliders has been proposed. We show that these suggestions are incorrect and based on errors in the simulation of multiple Compton scattering and in the calculation of the Compton spin-flip cross sections. We argue that the equilibrium polarization in this method is zero.

The basic theoretical ideas of the handbag mechanism for wide-angle exclusive scattering reactions are discussed and, with regard to the present experimental program carried out at JLab, its application to Compton scattering is reviewed in some detail. Results for other wide-angle reactions such as two-photon annihilations into pairs of hadrons or virtual Compton scattering are presented as well.

A new XMM-Newton observation has made possible a detailed study of both lobes of the radio galaxy Pictor A. Their X-ray emission is of non thermal origin and due to Inverse Compton scattering of the microwave background photons by relativistic electrons in the lobes, as previously found. In both lobes, the equipartition magnetic field (Beq ) is bigger than the Inverse Compton value

We calculate spin, charge, and azimuthal asymmetries in deeply virtual Compton scattering at leading twist-two level. The measurement of these asymmetries gives access to the imaginary and real part of all deeply virtual Compton scattering amplitudes. We note that a consistent description of this process requires taking into account twist-three contributions and we give then a model dependent e...