相关论文: The cyclo-synchrotron process and particle heating…
The high energy continuum in Seyfert galaxies and galactic black hole candidates is likely to be produced by a thermal plasma. There are difficulties in understanding what can keep the plasma thermal, especially during fast variations of…
There are difficulties in understanding what keeps the plasma thermalized in compact sources, especially during rapid variations of the emitted flux. Particle-particle collisions are too inefficient in hot rarefied plasmas, and a faster…
There is strong observational evidence that a quasi-thermal population of electrons (or pairs) exists in compact X-ray sources. It is, however, unclear what mechanism thermalizes the particles. Here, two processes, Coulomb scattering and…
Synchrotron self-Compton (SSC) scattering is an important emission mechanism in many astronomical sources, such as gamma-ray bursts (GRBs) and active galactic nuclei (AGNs). We give a complete presentation of the analytical approximations…
We present detailed calculations of the electron thermalization by synchrotron self-absorption accounting for cooling by Compton scattering. For the first time, we solve coupled kinetic equations for electrons and photons without any…
We present a complete solution to the cyclotron-synchrotron radiation due to an isotropic distribution of electrons moving in a magnetic field. We make no approximations in the calculations other than artificially broadening the harmonics…
In systems accreting well below the Eddington rate, the plasma in the innermost regions of the disk is collisionless and two-temperature, with the ions hotter than the electrons. Yet, whether a collisionless faster-than-Coulomb energy…
The electron-neutrino mass (or masses and mixing angles) may be directly measurable in weak electron-capture decays. The favoured experimental technique is "calorimetric". The optimal nuclide is $^{163}$Ho, and several experiments (ECHo,…
Quasi-thermal Comptonization in internal shocks formed between relativistic shells can account for the high energy emission of gamma-ray bursts. This is in fact the dominant cooling mechanism if the typical energy of the emitting particles…
In the standard synchrotron afterglow model, a power law of electrons is responsible for all aspects of photon production and absorption. Recent numerical work has shown that the vast majority of particles in the downstream medium are…
Soft cyclo-synchrotron photons produced by thermal electrons moving in a magnetic field can be subsequently Comptonized to produce hard X-ray and $\gamma$-ray emission. An accurate determination of the amount of soft cyclo-synchrotron…
In a hybrid thermal-nonthermal plasma, we find that the dominant emission and absorption mechanisms are synchrotron by nonthermal electrons and bremsstrahlung by thermal electrons. These two processes significantly change the spectrum from…
In the innermost regions of low-luminosity accretion flows, including Sgr A* at the center of our Galaxy, the frequency of Coulomb collisions is so low that the plasma is two-temperature, with the ions substantially hotter than the…
The synchrotron cooling of relativistic electrons is one of the most effective radiation mechanisms in astrophysics. It not only accompanies the process of particle acceleration but also has feedback on the formation of the energy…
The standard model for radio supernovae considers that the observed synchrotron radio emission arises from the high-energy shell that results from the strong interaction between the expanding supernova ejecta and the circumstellar medium.…
This work is a continuation of a previous effort (Panaitescu 2019) to study the cooling of relativistic electrons through radiation (synchrotron and self-Compton) emission and adiabatic losses, with application to the spectra and…
We discuss here constraints on the particle acceleration models from the observed gamma-ray bursts spectra. The standard synchrotron shock model assumes that some fraction of available energy is given instantaneously to the electrons which…
General expressions are obtained for the coefficient of light absorption by free carriers as well as the intensity of the spontaneous light emission by hot electrons in multivalley semiconductors. These expressions depend on the electron…
We study the effects of synchrotron self-absorption on the Comptonising electron distribution in the magnetised corona of accreting black holes. We solve the kinetic equations assuming that power is supplied to the coronal electrons through…
We provide a unified theoretical approach to the quantum dynamics of absorption of single photons and subsequent excitonic energy transfer in photosynthetic light-harvesting complexes. Our analysis combines a continuous mode <n>-photon…