Absorption of X-Rays

On the Absorption of X-rays in the Interstellar Medium

We present an improved model for the absorption of X-rays in the interstellar medium (ISM) intended for use with data from future X-ray missions with larger effective areas and increased energy resolution such as Chandra and the X-ray Multiple Mirror mission, in the energy range & 100 eV. Compared to previous work, our formalism includes recent updates to the photoionization cross section and r...

Subject headings: galaxies: general—galaxies: spiral—X-rays: general—X-rays: galaxies—X-rays: ISM

We present results from the analysis of deep ROSAT HRI and PSPC observations of the spiral galaxy M81. The inferred total (0.5–2 keV band) luminosity of M81 is ∼ 3×10 ergs s, excluding the contribution from identified interlopers found within the D25 ellipse. The nucleus of the galaxy alone accounts for about 65% of this luminosity. The rest is due to 26 other X-ray sources (contributing ∼ 10%)...

Diffraction of X-rays

Extragalactic Absorption of High Energy Gamma-Rays

The pair-production absorption of high-energy -rays by intergalactic low-energy photons is expected to produce a high-energy cuto in the spectra of sources which is a sensitive function of redshift. We rst discuss the expected absorption coe cient as a function of energy and redshift derived by Stecker and De Jager by making use of a new empirically based calculation of the spectral energy dist...

Directional fine structure in absorption of white x rays: A tomographic interpretation

P. Korecki,1,* M. Tolkiehn,2,3 D. V. Novikov,2 G. Materlik,4 and M. Szymonski1 1M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland 2Hamburger Synchrotronstrahlungslabor HASYLAB at Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, D-22603 Hamburg, Germany 3Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA 4Diamond...