We present an occultation of the central X-ray emitting region in the Seyfert Galaxy NGC 1365. This extreme spectral variation (from Compton-thin to reflection-dominated and back to Compton-thin in four days) has been caught in a ten days Chandra monitoring campaign consisting of six short (15 ks) observations performed every two days. We discuss the implications of this occultation within the ...

Introduction: We have investigated cardiac SPECT with slant hole collimator in which the holes are slanted towards the target organ, to provide greater sensitivity over the parallel hole collimator. In addition, parallel hole collimator was used to obtain a comparison in FWHM, sensitivity, Compton and photoelectric area values in the simulations. Materials and Methods...

The thermal Sunyaev-Zeldovich effect contains information about the history of Universe, which is observable in maps Compton $y$ parameter; however, it does not contain redshift sources. Recent papers have utilized a tomographic approach, by cross correlating map with locations galaxies known order to deproject signal along line sight. In this paper, we test validity and accuracy approach probe...

The evidence for particle acceleration in supernova shells comes from electrons whose synchrotron emission is observed in radio and X-rays. Recent observations by the HESS instrument reveal that supernova remnants also emit TeV g-rays, long-awaited experimental evidence that supernova remnants can accelerate cosmic rays up to the “knee” energies. Still, uncertainty exists whether these g-rays a...

Diiuse Galactic continuum-ray emission in the 0.75-30 MeV range from the whole sky has been studied using COMPTEL data from the rst 3 years of of the Compton Observatory. The imaging properties of COMPTEL enable spatial analysis of the-ray distribution using model tting. A model based on gas and inverse-Compton distributions in the Galaxy has been used to derive the intensity spectrum of the-ra...

The generation of an isolated attosecond gamma-ray pulse utilizing Compton backscattering of a relativistic electron bunch has been investigated. The energy of the electron bunch is modulated while the electron bunch interacts with a co-propagating few-cycle CEP (carrier envelope phase)-locked laser in a single-period wiggler. The energy-modulated electron bunch interacts with a counter-propaga...

The development of germanium Compton telescopes for nuclear γ-ray astrophysics (∼0.2-20 MeV) requires new event reconstruction techniques to accurately determine the initial direction and energy of photon events, as well as to consistently reject background events. This paper describes techniques for event reconstruction, accounting for realistic instrument/detector performance and uncertaintie...

We calculate the Equivalent Widht of the Core and the centroid energy and relative flux of the 1st order Compton Shoulder of the iron Kα emission line from neutral matter. The calculations are performed with Monte Carlo simulations. We explore a large range of column densities for both transmitted and reflected spectra, and study the dependence on the iron abundance. The Compton Shoulder is now...

In Compton cameras, the measured scattering angle is associated with an uncertainty which becomes larger as the incident gamma-ray energy decreases. Since this uncertainty degrades the spatial resolution of reconstructed images, Hirasawa and Tomitani (2003 Phys. Med. Biol. 48 1009-26) previously revised their analytical reconstruction algorithm to compensate for it. As the new algorithm improve...

Results of studies on Compton scattering imaging using synchrotron high-energy X-rays are reported. The technique is applied to a discharging coin cell, and the intensity of Compton scattered X-rays from the inside of the cell has been measured as a function of position and time. The position-time intensity map captures the migration of lithium ions in the positive electrode and reveals the str...