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Accretion Disks and Coronae in the X-Ray Flashlight
Maccarone, Thomas J.; Li, Jian; Kretschmar, Peter +10 more
Plasma accreted onto the surface of a neutron star can ignite due to unstable thermonuclear burning and produce a bright flash of X-ray emission called a Type-I X-ray burst. Such events are very common; thousands have been observed to date from over a hundred accreting neutron stars. The intense, often Eddington-limited, radiation generated in the…
Towards a Unified View of Inhomogeneous Stellar Winds in Isolated Supergiant Stars and Supergiant High Mass X-Ray Binaries
Fürst, Felix; Kretschmar, Peter; Wilms, Jörn +13 more
Massive stars, at least ∼10 times more massive than the Sun, have two key properties that make them the main drivers of evolution of star clusters, galaxies, and the Universe as a whole. On the one hand, the outer layers of massive stars are so hot that they produce most of the ionizing ultraviolet radiation of galaxies; in fact, the first massive…
Pulsar-Wind Nebulae and Magnetar Outflows: Observations at Radio, X-Ray, and Gamma-Ray Wavelengths
Mereghetti, Sandro; Reynolds, Stephen P.; Pavlov, George G. +3 more
We review observations of several classes of neutron-star-powered outflows: pulsar-wind nebulae (PWNe) inside shell supernova remnants (SNRs), PWNe interacting directly with interstellar medium (ISM), and magnetar-powered outflows. We describe radio, X-ray, and gamma-ray observations of PWNe, focusing first on integrated spectral-energy distributi…
Hard X-Ray/Soft Gamma-Ray Experiments and Missions: Overview and Prospects
Frontera, Filippo; Cavallari, Erica
Starting from 1960s, a great number of missions and experiments have been performed for the study of the high-energy sky. This review gives a wide vision of the most important space missions and balloon experiments that have operated in the 10-600 keV band, a crucial window for the study of the most energetic and violent phenomena in the Universe.…
Magnetic Fields of Neutron Stars in X-Ray Binaries
Mereghetti, Sandro; Revnivtsev, Mikhail
A substantial fraction of the known neutron stars resides in X-ray binaries—systems in which one compact object accretes matter from a companion star. Neutron stars in X-ray binaries have magnetic fields among the highest found in the Universe, spanning at least the range from ∼108 to several 1013 G. The magnetospheres around…
Implications of X-ray Observations for Electron Acceleration and Propagation in Solar Flares
Aschwanden, M. J.; Liu, W.; Zharkova, V. V. +6 more
High-energy X-rays and γ-rays from solar flares were discovered just over fifty years ago. Since that time, the standard for the interpretation of spatially integrated flare X-ray spectra at energies above several tens of keV has been the collisional thick-target model. After the launch of the Reuven Ramaty High Energy Solar Spectroscopic Imager (…
Properties of Energetic Ions in the Solar Atmosphere from γ-Ray and Neutron Observations
Vilmer, N.; MacKinnon, A. L.; Hurford, G. J.
Gamma-rays and neutrons are the only sources of information on energetic ions present during solar flares and on properties of these ions when they interact in the solar atmosphere. The production of γ-rays and neutrons results from convolution of the nuclear cross-sections with the ion distribution functions in the atmosphere. The observed γ-ray …
INTEGRAL: Science Highlights and Future Prospects
Wilms, Jörn; Winkler, Christoph; Ubertini, Pietro +1 more
ESA's hard X-ray and soft gamma-ray observatory INTEGRAL is covering the 3 keV to 10 MeV energy band, with excellent sensitivity during long and uninterrupted observations of a large field of view (∼100 square degrees), with ms time resolution and keV energy resolution. It links the energy band of pointed soft X-ray missions such as XMM-Newton wit…
The Impact of Space Experiments on our Knowledge of the Physics of the Universe
Giovannelli, Franco; Sabau-Graziati, Lola
With the advent of space experiments it was demonstrated that cosmic sources emit energy practically across all the electromagnetic spectrum via different physical processes. Several physical quantities give witness to these processes which usually are not stationary; those physical observable quantities are then generally variable. Therefore simu…