Related papers: Transverse coherence properties of X-ray beams in …

For synchrotron light sources, the brightness of user X-ray beams is primarily determined by the electron beam emittance and energy spread at operational intensity. A common feature of fourth-generation synchrotrons is the short length of…

We present an analysis of the spectral properties of the extragalactic radio sources in the nearly-complete VSA sample at 33GHz. Data from different surveys are used to study source spectra between 1.4 and 33GHz. We find that, in general,…

Using RXTE/ASM archival data, we investigate the behaviour of the spectral hardness ratio as a function of X-ray luminosity in a sample of six transient X-ray pulsars (EXO 2030+375, GX 304-1, 4U 0115+63, V 0332+63, A 0535+26 and MXB…

Model equations for describing and efficiently computing the radiation profiles of tightly spherically-focused higher-order electromagnetic beams of vortex nature are derived stemming from a vectorial analysis with the complex-source-point…

Some rapidly variable extra-galactic radio sources show very high brightness temperatures T_B>10^{12}K and high degrees of circular polarisation (1%). Standard synchrotron models that assume a power-law electron distribution cannot produce…

Methods. We analyzed broadband XMM-Newton and NuSTAR observations of NGC 300 ULX1, performing phase-averaged and phase-resolved spectroscopy. We compared two physically motivated models for the source spectrum: Non-thermal accretion column…

When measuring diameters of partially resolved sources often a technique called gaussian deconvolution is used. This technique yields a gaussian diameter which subsequently has to be multiplied with a conversion factor to obtain the true…

In the framework of statistical optics, a Wigner function represents partially coherent radiation. A Gaussian Wigner function, which is an equivalent representation of the more commonly used Gaussian Schell-model cross-spectral density, may…

For the low density filamentary and sheet-like structures in the warm ($\sim 10^4$ to $\sim 10^6$ K) IGM predicted by numerical simulations the resonant line scattering of X-ray background (XRB) photons by He and H-like ions of heavy…

The role played by the intergalactic medium (IGM) in the X-ray absorption towards high-redshift sources has recently drawn more attention in spectral analysis studies. Here, we study the X-ray absorption towards 15 flat-spectrum radio…

We consider the inverse source problem of a fixed wavenumber: study properties of an acoustic source based on a single far- or near-field measurement. We show that nonradiating sources having a convex or non-convex corner or edge on their…

A recent "beam splitting" experiment at LCLS apparently demonstrated that after a microbunched electron beam is kicked on a large angle compared to the divergence of the FEL radiation, the microbunching wave front is readjusted along the…

We investigate synchrotron emission models as the source of gamma-ray burst spectra. We show that including the possibility for synchrotron self-absorption, a ``smooth cutoff'' to the electron energy distribution, and an anisotropic…

Reconstructing the unknown spectrum of a given X-ray source is a common problem in a wide range of X-ray imaging tasks. For high-energy sources, transmission measurements are mostly used to recover the X-ray spectrum, as a solution to an…

Incoherent Diffraction Imaging - IDI - is a diffraction-based imaging technique that has been recently proposed to exploit the partial coherence of incoherently scattered light to retrieve structural information from the scattering centers.…

When measuring diameters of partially resolved sources like planetary nebulae, H II regions or galaxies, often a technique called gaussian deconvolution is used. This technique yields a gaussian diameter which subsequently has to be…

We present optical and X-ray data for a sample of serendipitous XMM-Newton sources that are selected to have 0.5-2 keV vs 2-4.5 keV X-ray hardness ratios which are harder than the X-ray background. The sources have 2-4.5 keV X-ray flux >=…

A number of recent lines of evidence point towards the presence of hot, out-flowing plasma from the central regions of compact Galactic and extragalactic X-ray sources. Additionally, it has long been noted that many of these sources exhibit…

A formalism is developed which allows to determine the locations of all local symmetry axes of three-dimensional particles with overall icosahedral symmetry. It relies on the fact that the root system of the non-crystallographic Coxeter…

The total luminosity and spectral shape of the non-thermal emission produced by cosmic rays depends on their interstellar environment, a dependence that gives rise to correlations between galaxies' bulk properties -- star formation rate,…