Synchrotron emission

The discovery of a prompt radio burst is related to the epoch of shock break-out was an important Australian contribution to the studies of SN1987A. The burst lasted for only about a week, (Turtle et al. ), and can be understood in terms of free-free absorption of synchrotron emission (Storey and Manchester). The location of this radio emission was probably in the shocked stellar wind region of the star, with the free-free absorption arising from within this layer. The thickness of the emitting layer was estimated at only 4.8% of the radius, which would be consistent with a power law density distribution of matter with an index of 11.8. Since the first week, the radio emission continued to fade (despite some other reports to the contrary), becoming effectively unobservable at 843MHz after about 50 days. 

Figure 5.3. Left. The gamma-ray emission from XX annihilation in a rich, Coma-like, nearby galaxy cluster is shown Mx = 70 — 500 GeV (from top down). The integral flux is compared to the sensitivity of ongoing and planned gamma-ray experiments, as labelled. Right. The diffuse synchrotron emission spectrum of secondary electrons produced in XX annihilation is shown to fit the Coma radio-halo spectrum the green area represent the prediction of a model in which the x annihilates predominantly into fermions, while the blue area represent the gauge-boson dominated x annihilation (from Colafrancesco Mele 2001).

The cosmic ray electrons which are responsible for the radio-halo and relic synchrotron emission inevitably Compton scatter the CMB (as well as other local background) photons which will then gain energy and emit at higher energy E ss 2.7 keV (E/GeV)2. Electrons with E E a few GeV produce emission in the HXR range, while electrons with E < 400 MeV produce soft X-rays and UV emission. There is actually evidence for an excess of emission w.r.t. the thermal bremsstrahlung emission by the hot IC gas in about 20 nearby clusters... 

The Galactic Centre could provide a smoking gun" with radio synchrotron, 7-ray and v data annihilations measure cold dark matter where Milky Way formation began inside-out", some 12 Gyr ago. Accretion models onto the central black hole fail to give sufficient low frequency radio or gamma ray emission to account for the observed fluxes from SagA, and it is tempting to invoke a more exotic alternative. For example, the low frequency radio emission can be explained by spike-enhanced self-absorbed synchrotron emission,... 

One kind of X-ray lasers is a subcase of the so-called free electron laser. Electrons, accelerated are forced, to almost the speed of light ("relativistic electrons") by klystrons and then bent or wiggled in special magnets called undulators are forced to emit some of their energy as synchrotron radiation inside the undulator, the synchrotron pulses can induce in-phase synchrotron emission by other electrons, thus producing a pulse at X-ray wavelengths. This was recently demonstrated as almost possible (2009). 

The availability of a complete range of photon energies from storage ring synchrotron emission has allowed the formation and decay of some exotic inner-shell hole states to be studied. The formation of double core-hole states, where two electrons are removed from the same inner shell by direct photoionization is expected to be weaker by several orders of magnitude than the formation of doubly charged ions with two vacancies in the valence shell... 

Synchrotron emission Nonthermal radiation produced by free relativistic electrons spiraling in magnetic fields. 

The synchrotron emission from the diffuse interstellar medium is the most direct measure of the overall magnetic... 

A single charged electron moving in a magnetic field is accelerated unless its velocity is solely in the direction of the magnetic field. This causes the electron to emit electromagnetic waves. The nature of these waves depends on whether the electron is nonrelativistic (velocity 3 x 10 ° cm/sec) or relativistic (velocity 3 x 10 ° cm/sec). The radiation emitted by nonrelativistic electrons is referred to as cyclotron radiation radiation emitted by relativistic electrons is referred to as synchrotron emission. 

A single electron of energy E radiates synchrotron emission with an intensity spectrum that varies as (v is frequency) up to a critical frequency 0.29vo and decreases exponentially at higher frequencies. The critical frequency is defined as... 

FIGURE 11 Schematic representation of the spectrum of Jupiter, showing the frequency ranges for which atmospheric emission dominates, synchrotron emission dominates, and sporadic nonthermai emission dominates. 

Radio interferometric maps of Jupiter s synchrotron emission have been made at a number of different wave-... 

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