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Topic: Synchrotron emission

	Untitled Document
		Names such as cyclotron emission and magnetobremsstrahlung are used to describe the emission from nonrelativistic and mildly relativistic electron energies, whereas the name synchrotron radiation is traditionally reserved for highly relativistic electrons because it was first observed in 1948 in electron synchrotrons.
		Synchrotron radiation is characterized by a generation of frequencies appreciably higher than the cyclotron frequency of electrons (or positrons) in a magnetic field, a continuous spectra whose intensity decreases with frequency beyond a certain critical frequency, highly directed beam energies, and polarized electromagnetic wave vectors.
		Synchrotron radiation was first brought to the attention of astronomers by H. Alfvn; and N. Herlofson in 1950, a remarkable suggestion at a time when plasma and magnetic fields were thought to have little, if anything, to do in a cosmos filled with ÒislandÓ universes (galaxies).
	public.lanl.gov /alp/plasma/synchrotron.html (676 words)

	Radio Emission
		Non-thermal emission, which does not depend on the temperature of the emitting object, includes synchrotron radiation, gyrosynchrotron emission from pulsars, and amplified emission from masers in space.
		In fact, it is quite the opposite, with emission increasing at longer wavelengths.The most common form of non-thermal emission found in astrophysics is called synchrotron emission.
		For this emission to be strong enough to have any astronomical value, the electrons must be traveling at nearly the speed of light when they encounter a magnetic field; these are known as "relativistic" electrons.
	www.nrao.edu /whatisra/mechanisms.shtml (2526 words)

	Extended Emission: Spectral Imaging
		Synchrotron emission from galaxies is most readily studied at frequencies below a few GHz, since both the flux density and the size of the primary beam increase as one moves to lower and lower frequencies.
		Knowledge of the true thermal emission is also critical to disentangling the thermal and non-thermal emission, as discussed in the next section.
		The primary difficulty in disentangling synchrotron emission with varying spectral index from thermal emission is the limited spectral range now available.
	www.cv.nrao.edu /vla/upgrade/node70.html (1235 words)

	radio cwb
		The thermal emission arises naturally from free electrons in their powerful winds, but in addition to magnetic fields, synchrotron emission requires a population of relativistic electrons, widely thought to be accelerated in shocks within the stellar winds of the star.
		Synchrotron emission from the wind collision shock is clearly visible between the thermal emission from the wind of each star.
		Absorption by the wind of the companion blocks out some of the synchrotron emission from the wind-wind collision, while emission from the wind of the primary is seen towards the bottom of the image.
	www.ast.leeds.ac.uk /~jmp/New/radio_cwb.html (543 words)

	Untitled Document (Site not responding. Last check: 2007-09-27)
		Thermal emission is derived from the heat energy of the emitting object itself.
		Cyclotron emission is caused by the acceleration of a charged particle by electric and magnetic fields, in astronomical sources this is mostly caused by magnetic fields.
		Synchrotron emission is caused by the acceleration of relativistic electrons by a magnetic field.
	web.haystack.mit.edu /education/sources.html (250 words)

	Synchrotron Radiation
		Emission from a single electron will clearly be elliptically polarized with the electric field vector perpendicular to the projected magnetic field vector.
		Linear polarization and a negative spectral index are the two defining characteristics used to identify sources of synchrotron emission, although either is usually sufficient to identify the emission mechanism.
		Hence, while detection of linearly polarized emission is a strong proof of synchrotron emission, a lack of it cannot rule it out.
	www.ncra.tifr.res.in /~sanjay/thesis/node8.html (595 words)

	Non-Thermal Models
		8) shows that the X-ray emission of the western hot spot cannot be synchrotron radiation from a high energy extension of the population of electrons responsible for the radio to optical synchrotron radiation.
		Assuming that the electrons are continuously accelerated in the hot spot, we may interpret the turnover frequency as the frequency at which the ``half-life'' to synchrotron losses of the radiating electrons is equal to their escape time from the hot spot.
		However, the observed radio-optical synchrotron radiation, as well as the radio synchrotron radiation of the hypothesised component, is available for scattering by the hypothetical low energy electron population.
	www.astro.caltech.edu /~pls/papers/apj/PicA/node19.html (1477 words)

	X-rays from Free Electrons
		The most common situation is the emission from a hot gas as the electrons collide with the nuclei due to their random thermal motions.
		Synchrotron radiation is associated with the acceleration suffered by electrons as they spiral around a magnetic field.
		Cyclotron and synchrotron radiation are strongly polarized; detection of polarization is regarded as strong observational evidence for synchrotron or cyclotron radiation.
	imagine.gsfc.nasa.gov /docs/science/how_l2/xray_generation_el.html (922 words)

	Jupiter'S Synchrotron Radiation
		Substantial increases in the planet's synchrotron emission were reported by several research teams (Ref. 1) during the week of July 16-23 at numerous wavelengths spanning the decimetric spectrum.
		The data show that the synchrotron flux at 13-cm increased 27 percent during the week of the impacts in July 1994 and was followed by a steady decline that began in August and continued throughout 1995.
		The downward sloping baseline is consistent with the long-term decline in Jupiter's synchrotron emission that began in 1991-92, and may be related to the current minimum in the 11-year cycle of sunspots and solar magnetic storms.
	deepspace.jpl.nasa.gov /technology/TMOT_News/AUG97/jupsrado.html (933 words)

	Bonn-2004: Multiband Approach to AGN
		The high-energy emission from these relativistic electrons will tend to dominate the observed luminosity at sites that are compact and/or collimated into highly relativistic outflows, i.e., mainly in the jets we see on milliarcsecond and arcsecond scales.
		Jet X-ray emission is confused, to varying degrees, with that from the central engine, but can be measured, at least in a statistical sense, through considerations of the multiwaveband spectrum and the level of intrinsic absorption.
		This radiation is collimated even more strongly than the synchrotron emission (by the 6th power of the Doppler factor instead of the 4th) and, therefore, its domination is expected to drop with the increase of the angle of view away from the jet axis.
	www.mpifr-bonn.mpg.de /bonn04/abstract-files.html (7686 words)

	Radio Emission from Giant Planets (Site not responding. Last check: 2007-09-27)
		The most common form of radio emission is by way of Synchrotron Radiation - which is a non-thermal method of emission.
		Saturn: no synchrotron component is seen, although it would be there if it were not for the presence of the rings, which disturb the relativistic electrons.
		In this case, the emissions are not from the planet, but from solar radiation trapped in the large magnetic fields of these planets.
	astronomyonline.org /Stars/PlanetaryEmission.asp?Cate=Stars&SubCate=ST01&SubCate2=PlanetaryEmission (392 words)

	ESO - 2002
		The radio emission depicted here is synchrotron emission caused by high-speed electrons that move in the magnetic field carried along with the plasma [2].
		The central area (with the strongest emission) indicates where the jet from the galaxy hits the intergalactic medium; the two others represent synchrotron emission from electrons accelerated in secondary processes at these sites.
		The central area (with the strongest emission) is where the plasma jet from the galaxy centre hits the intergalactic medium.
	www.eso.org /outreach/press-rel/pr-2002/phot-26-02.html (1092 words)

	SNR & ISM -- October 3, 1996 (Site not responding. Last check: 2007-09-27)
		Synchrotron emission from electrons in the 1-300 GeV range should allow us to measure the energy spectrum (and magnetic field) throughout the Galaxy.
		There's only one catch: at high latitudes, the synchrotron emission (predicted by radio surveys) is missing from microwave surveys.
		The amount of synchrotron emission did seem to be correlated with H alpha and H I. Summary
	spider.ipac.caltech.edu /staff/keohane/SNR_ISM/96_10_03.html (751 words)

	Synchrotron Emission from the Water Maser Source in W3OH (Site not responding. Last check: 2007-09-27)
		Synchrotron Emission from the Water Maser Source in W3OH
		These observations provide strong evidence for synchrotron emission from an inhomogeneous source.
		The elongated continuum source is coincident within 0.1 arcsec of the center of expansion of the H$_2$O masers and is aligned with the dominant H$_2$O outflow pattern.
	www.aas.org /publications/baas/v26n4/aas185/abs/S9601.html (199 words)

	Research highlights - AGNs
		The second emission component extends through X-ray and gamma-ray energies and might be due to Compton upscattering of lower-energy radiation by the same relativistic electrons which are responsible for the synchrotron emission at lower frequencies (however, there are alternative models in which the high-energy emission is produced by hadronic processes in the jet).
		Unfortunately, the synchrotron peak in quasars is generally located in the infrared, where it is notoriously hard to observe.
		In the case of quasars, this high-energy cutoff of the synchrotron spectrum is usually located in the ultraviolett spectral regime, which is heavily absorbed by interstellar gas and dust, and thus virtually impossible to observe for most objects.
	www.phy.ohiou.edu /~mboett/agn_main.html (3818 words)

	Gamma-ray bursters cross the Line of Death
		The light curves of the few known optical and X-ray counterparts are consistent with that of an expanding fireball that is glowing because of a "Synchrotron Shock".
		Synchrotron emission is seen all the time here on Earth as a blue glow in particle accelerators, and radio astronomers detect it coming from the Milky Way.
		The Synchrotron Shock Model predicts that the slope of the line that fits the lower energy part of the spectrum cannot be greater than -2/3.
	science.nasa.gov /newhome/headlines/ast13oct98_1.htm (968 words)

	ASCA Science Highlights: SNR
		The nonthermal rim emission has been interpreted as synchrotron emission from electrons with energies up to 100 TeV accelerated in the remnant blast wave (Reynolds 1996 ApJ 459, L13) thereby providing the first clear link between particle acceleration at SN shock fronts and high-energy cosmic rays in the Galaxy.
		The task of identification is further complicated by the occasional presence of thermal X-ray emission from the SN blast wave which may accompany the plerionic emission in the so-called ``composite'' remnants.
		The sharpness of the pulse is compelling consistency argument in favor of emission by relativistic particles.
	heasarc.gsfc.nasa.gov /docs/asca/science/science_snr.html (3291 words)

	ELETTRA - BL 9.1 - Source for Imaging and Spectroscopic Studies in the Infrared (SISSI)
		The infrared beamline SISSI (Source for Imaging and Spectroscopic Studies in the Infrared) at Elettra extracts the IR and visible components of synchrotron emission for applications of spectroscopy, microspectroscopy and imaging.
		The pump beam can be provided by either a synchronized external laser source or the synchrotron emission itself, and the probe beam is provided by the beamline emission.
		The brightness of the emission allows determining the position of an object with a precision of 1 micron by frequency-dependent reflection contrast in the mid- and near-infrared range.
	www.elettra.trieste.it /experiments/beamlines/sissi (465 words)

	No Title
		Understanding and modeling emission from SNRs contributes to the knowledge of physics in strong shocks, a study that includes such far ranging topics as the earth's bow shock, extragalactic jets and star formation.
		Predictions were made by Reynolds (1998) that synchrotron emission would extend up to X-ray energies and then roll off due to remnant age, particle escape or radiative losses.
		I have demonstrated that a detailed model of synchrotron emission is capable of describing the spectrum of SN 1006, a dominantly nonthermal supernova.
	www.aoc.nrao.edu /~kdyer/pastwork.html (1725 words)

	Time-Dependent Simulation of Synchrotron Emission and Electron Shock Acceleration in Radio Galaxies
		The focus of this project is to develop a better understanding of the nature of radio jets, primarily those associated with Fanaroff and Riley Type I and II sources.
		The simulations demonstrate that the properties and patterns of the relativistic particle populations and emissions are fundamentally influenced by the inherently unsteady behavior of jet flows.
		Note that the individual frames which comprise this animation have not been scaled to a "universal" colorbar, which is why the source appears to undergo dramatic fluctuations in brightness.
	www.msi.umn.edu /Projects/twj/radjet/radjet.html (1406 words)

	Synchrotron Emission from an MHD jet (Site not responding. Last check: 2007-09-27)
		Synchrotron Emission from a 3-D MHD Simulation of an Astrophysical Jet
		This animation is from a ZEUS-3D MHD simulation of a low density (2% of the ambient density), Mach 6 jet with a weak magnetic field propagating into a uniform ambient medium.
		This particular sequence depicts the time evolution of the total synchrotron intensity as integrated through the 3-D data cube along the line of sight.
	apwww.stmarys.ca /~dclarke/totiaj.html (177 words)

	Timothy J. Thompson's Publications
		We were eventually able to draw direct correlations between the synchrotron emission, and the solar wind loading of the Jovian magnetosphere.
		Preliminary results of a study to search for plausible correlations between the Jovian synchrotron emission and solar-related phenomena reveal that a positive correlation may exist with the ion number density in the solar wind.
		Data from 1963 through 1985 were analyzed, and the results suggest that many solar wind parameters are correlated with the intensity of the synchrotron emission produced by the relativistic electrons in the Jovian Van Allen radiation belts.
	www.tim-thompson.com /research.html (2229 words)

	Multifreq. Pol. Monitoring of Blazars
		This explains the common observation of weak correlations between low-frequency flares and X-ray or even gamma-ray flares: Since the synchrotron photons at one waveband (for example optical wavelengths) can come from different locations in the jet than those at another waveband, there might be little correlation between variations at the two bands on short timescales.
		Because higher-energy electrons emit synchrotron radiation at higher frequencies, the emission at these frequencies is confined to a thin volume immediately behind the shock front.
		Because of this, it is possible for "reverse" time delays (radio, IR, or optical flares that peak before the X-ray or gamma-ray maximum) to occur in the case of synchrotron self-Compton (SSC) emission (i.e., when the seed photons are synchrotron radiation from the same population of relativistic electrons that do the scattering).
	www.bu.edu /blazars/emissionmodels.html (739 words)

	Concluding Remarks
		It is, however, difficult to understand why the X-rays from both the jet and the hot spot should correlate so well with synchrotron radio emission, which must arises in a relatively strong magnetic field.
		Addition of this synchrotron emission to the synchrotron self-Compton emission expected for a magnetic field a factor of 9 below equipartition reproduces the observed spectrum (see Fig.
		We feel that synchrotron radiation is the most likely X-ray emission process of both jet and hot spot.
	www.astro.caltech.edu /~pls/papers/apj/PicA/node23.html (1151 words)

	LTSA/winning abstracts
		As the sample of remnants identified to emit X-ray synchrotron emission grows, we will use the spectral and spatial information about the X-ray synchrotron emission to study the acceleration of cosmic-ray electrons in supernova remnants.
		The work may also help determine if X-ray synchrotron emission is preferentially associated with the remnants of type Ia or type II supernovae and if the emission is preferentially associated with low-density or high-density regions around the remnants (i.e.
		Because UV radiation is absorbed by the large quantities of dust surrounding this activity and re-emitted mainly in the infrared, excitation and extinction diagnostics are limited to infrared and radio wavelengths in these infrared-bright galaxies.
	research.hq.nasa.gov /code_s/nra/current/NRA-99-OSS-01/99ltsa.html (6808 words)

	Energy Citations Database (ECD) - - Document #6482964
		For copies of other documents, please see the Availability, Publisher, Research Organization, Resource Relation and/or Author (affiliation information) fields and/or Document Availability.
		Spectrum of synchrotron emission parallel to a magnetic field for relativistic loss-cone-type energy distributions
		Calculations of the spectrum of synchrotron emission parallel to a magnetic field are presented for relativistic loss-cone-type distribution functions in the tenuous-plasma limit.^Substantial deviations from the result for an isotropic Maxwellian are obtained.
	www.osti.gov /energycitations/product.biblio.jsp?osti_id=6482964&query_id=0 (178 words)

	[32P.24] Modeling Jupiter's Synchrotron Emission (Site not responding. Last check: 2007-09-27)
		A model of Jupiter's synchrotron emission will be presented.
		Jupiter's synchrotron emission originates from the motion of high energy relativistic electrons trapped in Jupiter's magnetic field and is emitted in an extremely narrow beam in the direction of the electron's motion.
		This provides the basis for the utilization of the model and remote observations to investigate the electron distribution and magnetic field configuration deep within Jupiter's magnetosphere.
	www.aas.org /publications/baas/v30n3/dps98/354.htm (169 words)

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