نتایج جستجو برای: nonthermal
تعداد نتایج: 2468 فیلتر نتایج به سال:
We show that the hard X-ray (HXR) emission observed from several galaxy clusters is naturally explained by a simple model, in which the nonthermal emission is produced by inverse Compton scattering of cosmic microwave background photons by electrons accelerated in cluster accretion shocks: The dependence of HXR surface brightness on cluster temperature is consistent with that predicted by the m...
Pulsars emit from low-frequency radio waves up to high-energy gamma-rays, generated anywhere from the stellar surface out to the edge of the magnetosphere. Detecting correlated mode changes across the electromagnetic spectrum is therefore key to understanding the physical relationship among the emission sites. Through simultaneous observations, we detected synchronous switching in the radio and...
The possibility that the peak of the spectral energy distribution (SED) of prompt GRB emission is produced on compact scales, prior to the acceleration of the fireball to its terminal Lorentz factor is considered. It is argued that if dissipation on these scales is associated with pair creation processes, then the observed clustering of SED peaks can be accounted for quite naturally by this mec...
We study the spectral distortions of the cosmic microwave background radiation induced by the effect in clusters of galaxies when the target electrons have a modified Maxwell-Boltzmann distribution with a high-energy nonthermal tail. Bremsstrahlung radiation from this type of electron distribution may explain the suprathermal X-ray emission observed in some clusters such as the Coma Cluster and...
After the positive detection by BeppoSAX of hard X-ray radiation up to approximately 80 keV in the Coma Cluster spectrum, we present evidence for nonthermal emission from A2256 in excess of thermal emission at a 4.6 sigma confidence level. In addition to this power-law component, a second nonthermal component already detected by ASCA could be present in the X-ray spectrum of the cluster, which ...
Clusters of galaxies generally form by the gravitational merger of smaller clusters and groups. Major cluster mergers are the most energetic events in the Universe since the Big Bang. Mergers drive shocks into the intracluster gas, and these shocks heat the intracluster gas, and should also accelerate nonthermal relativistic particles. The X-ray signatures of the thermal effects of merger shock...
Galaxy clusters are the most massive constituents of the large-scale structure of the universe. Although the hot thermal gas that pervades galaxy clusters is relatively well understood through observations with x-ray satellites, our understanding of the nonthermal part of the intracluster medium (ICM) remains incomplete. With Low-Frequency Array (LOFAR) and Giant Metrewave Radio Telescope (GMRT...
Analytic approximations for synchrotron, synchrotron self-Compton (SSC), and external Compton (EC) processes are used to constrain model parameters for knot and hot-spot emission in extended jets of radio galaxies. Equipartition formulas are derived that relate the Doppler factor δ and comoving magnetic field B assuming a nonthermal synchrotron origin of the radio emission, and synchrotron, SSC...
Gamma-ray astronomy will play a crucial role in the investigation of nonthermal processes in the large scale structure of the universe. Particularly, galaxy clusters (GC) observations at this photon energy will help us understand the the origin of radio emitting high energy particles, the possible level of cosmic-ray (CR) pressure in intracluster environment, and the strength of intracluster ma...
We discuss images of M87 from 3.6 to 160 μm obtained with Spitzer. As found previously, there is an excess in the far infrared over a simple power law interpolation from the radio to the resolved nonthermal features in the mid-infrared and optical. We show that this excess is most likely warm dust in the galaxy itself, and that the properties of this emission component are similar to the far in...
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