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A lot of beautiful observations of Supernova remnant 1987A give a precise idea of its structure and its evolution. The regular interpretations of the observations set that the large energy needed to explain the brightness of the pearl…
We discuss the X-ray emission observed from Supernova Remnant 1987A with the Chandra X-ray Observatory. We analyze a high resolution spectrum obtained in 1999 October with the high energy transmission grating (HETG). From this spectrum we…
We study the peripheral ion collisions at LHC energies in which a nucleus is excited to the discrete state and then emits $\gamma$-rays. Large nuclear Lorenz factor allows to observe the high energy photons up to a few ten GeV and in the…
Turbulent radiation flow is commonplace in systems with strong, incoherent, light-matter interactions. In astrophysical contexts, photon bubble turbulence is considered a key mechanism behind enhanced radiation transport, and its importance…
We report on the discovery of a shell-type supernova remnant in the southern sky. It is a large (8*8), low-brightness source with a nonthermal radio spectrum, which requires background filtering to isolate it from the diffuse background…
Radiation by the atoms of a resonant medium is a cooperative process in which the medium participates as a whole. In two previous papers \cite{PG00,GP00}, we treated this problem for the case of a medium having slab geometry, which, under…
Dark photon dark matter will resonantly convert into visible photons when the dark photon mass is equal to the plasma frequency of the ambient medium. In cosmological contexts, this transition leads to an extremely efficient, albeit…
We point out a few remarkable properties of the $\gamma\gamma\to\gamma\gamma$ process at high energy. They should allow to search for effects of new particles and interactions. We give illustrations with threshold effects due to pairs of…
There has recently been interest in the role of inverse bremsstrahlung, the emission of photons by fast suprathermal ions in collisions with ambient electrons possessing relatively low velocities, in tenuous plasmas in various astrophysical…
The low energy spectral slopes of the prompt emission of most gamma-ray bursts (GRBs) are difficult to reconcile with radiatively efficient optically thin emission models irrespective of the radiation mechanism. An alternative is to ascribe…
We analyze the obtained solutions of the non-linear Shroedinger equation for spherically and axially symmetrical electrons density oscillations in plasma. The conditions of the oscillations process existence are examined. It is shown that…
Coherent light sources, such as free electron lasers, provide bright beams for biology, chemistry, physics, and advanced technological applications. Increasing the brightness of these sources requires progressively larger devices, with the…
Ionization by relativistically intense short laser pulses is studied in the framework of strong-field quantum electrodynamics. Distinctive patterns are found in the energy probability distributions of photoelectrons. Except of the already…
Bubble formation in liquid xenon underneath a Thick Gaseous Electron Multiplier (THGEM) electrode immersed in liquid xenon was observed with a CCD camera. With voltage across the THGEM, the appearance of bubbles was correlated with that of…
Photon spheres, surfaces where massless particles are confined in closed orbits, are expected to be common astrophysical structures surrounding ultracompact objects. In this paper a semiclassical treatment of a photon sphere is proposed. We…
Numerous sources produce the ionization impact on the planetary atmosphere. The tropospheric cloudiness therewith is originated at such altitudes, which coincide with places of the maximum of the atmospheric ionization that caused by space…
Electrons at the surface of a plasma that is irradiated by a laser with intensity in excess of $10^{23}~\mathrm{W}\mathrm{cm}^{-2}$ are accelerated so strongly that they emit bursts of synchrotron radiation. Although the combination of high…
Sonoluminescence is the intriguing phenomenon of strong light flashes from tiny bubbles in a liquid. The bubbles are driven by an ultrasonic wave and need to be filled with noble gas atoms. Approximating the emitted light by blackbody…
We study the interaction of intense ultrashort laser pulses with cryogenic He jets using 2d/3v relativistic Particle-in-Cell simulations (XOOPIC). Of particular interest are laser intensities $(10^{15}-10^{20})$ W/cm$^2$, pulse lengths $\le…
We investigate the importance of the pseudo-continuum bound-free opacity from hydrogen atoms in the atmospheres of cool white dwarfs. This source of absorption, when calculated by the occupation probability formalism applied in the modeling…