Related papers: Reflection at large distance from the central engi…
Refraction, traditionally viewed as a geometric event occurring at material interfaces, is now being re-examined through the lens of coherence. Recent studies in optics and photonics, including coherence tomography, Moire interference, and…
Accreting black holes and neutron stars in their hard (low) state show not only very similar X/gamma-ray spectra but also that the behaviour of their light curves is quite similar which can be quantified as having similar power-density…
Understanding disc-corona geometry through X-ray reverberation variability studies in Seyfert galaxies is crucial, yet our knowledge mostly relies on flux-averaged mean spectral analysis. In this study, we investigate the origin of the…
This study describes both experimentally and theoretically an important hitherto undiscovered feature of the scattering of micron_sized spherical objects when illuminated with highly focused circularly polarized light. This is a regime of…
Relativistically expanding sources of X-rays and gamma-rays cover an enormous range of (central) compactness and Lorentz factor. The underlying physics is discussed, with an emphasis on how the dominant dissipative mode and the emergent…
X-ray-emitting symbiotic stars exhibit a variety of spectral shapes classified as $\alpha$, $\beta$, $\gamma$, $\delta$ and $\beta$/$\delta$ types, which have been attributed to different phenomena such as thermonuclear burning on the…
We present RXTE monitoring observations of the Seyfert 2 galaxy Mrk 348 spanning a 6 month period. The time-averaged spectrum in the 3-20 keV band shows many features characteristic of a Compton-thin Seyfert 2 galaxy, namely a hard…
Eliminating reflections caused by incident light interacting with reflective medium remains an ill-posed problem in the image restoration area. The primary challenge arises from the overlapping of reflection and transmission components in…
The radiation of a Fast Radio Burst (FRB) reflects from the Moon and Sun. If a reflection is detected, the time interval between the direct and reflected signals constrains the source to a narrow arc on the sky. If both Lunar and Solar…
We develop a Monte-Carlo code to compute the Compton scattered X-ray flux arising from a hot inner flow which undergoes Lense-Thirring precession. The hot flow intercepts seed photons from an outer truncated thin disk. A fraction of the…
We present a study of the hard X-ray spectrum (>15 keV) of different classes of Seyfert galaxies observed with BeppoSAX/PDS. Using hard X-ray data, we avoid absorption effects modifying the Seyfert emission and have direct access to the…
Fraunhofer diffraction plays a vital role in experimental physics not only because it accurately describes the behaviour of light in the usual propagation limit, but also because it links the diffracted light with the scattering object…
We report on the first observation of the Seyfert 1 galaxy NGC4593 in the 0.1-200 keV band, performed with the BeppoSAX observatory. Its spectral components are for the first time simultaneously measured: a power-law with photon spectral…
We investigate optical characteristics of flashes caused by impacting meter- to decameter-sized outer solar system objects on Jupiter and contributions of reflected light from surface clouds at visible wavelengths to estimate more accurate…
We develop a quantitative description of giant asymmetry in reflectance, recently observed in semicontinuous metal films. The developed scaling-theory based technique reproduces the spectral properties of semicontinuous composites, as well…
Complex narrow line Seyfert 1s (NLS1s), such as 1H0707-495, differ from simple NLS1s like PG1244+026 by showing stronger broad spectral features at Fe K and larger amplitude flux variability. These are correlated: the strongest Fe K…
All optical systems, which involve the collimation of a reflected, transmitted or scattered wave subsequent to tight focusing, are subject to two kinds of deviations. One is the wavefront curvature due to inaccurate focal placement of the…
We present the first results from a detailed spectral-timing analysis of a long ($\sim$130 ks) XMM-Newton observation and quasi-simultaneous NuSTAR and Swift observations of the highly-accreting narrow-line Seyfert 1 galaxy Mrk 1044. The…
Relativistic mirrors can be realized with strongly nonlinear Langmuir waves excited by intense laser pulses in underdense plasma. On reflection from the relativistic mirror the incident light affects the mirror motion. The corresponding…
The bright and highly-variable Seyfert I Active Galactic Nucleus, IC4329A, was observed with Suzaku 5 times in 2007 August with intervals of ~ 5 days, and a net exposure of 24-31 ks each. Another longer observation was carried out in 2012…