Inverse-Compton Gamma Rays From Plerions

1996 ◽  
pp. 257-268
Author(s):  
Alice K. Harding
Keyword(s):  
Gamma Rays ◽  
Inverse Compton

GAMMA-RAY BURSTS AS VHE-UHE SOURCES

2008 ◽  
Vol 17 (09) ◽  
pp. 1319-1332
Author(s):  
PETER MÉSZÁROS
Keyword(s):  
Cosmic Rays ◽  
Gamma Rays ◽  
Lower Energy ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Model Parameters ◽  
Fundamental Interaction ◽  
Acceleration Mechanism ◽  
Inverse Compton ◽  
Tev Gamma Rays

Gamma-ray bursts are capable of accelerating cosmic rays up to GZK energies Ep ~ 1020 eV, which can lead to a flux at Earth comparable to that observed by large EAS arrays such as Auger. The semi-relativistic outflows inferred in GRB-related hypernovae are also likely sources of somewhat lower energy cosmic rays. Leptonic processes, such as synchrotron and inverse Compton, as well as hadronic processes, can lead to GeV-TeV gamma-rays measurable by GLAST, AGILE, or ACTs, providing useful probes of the burst physics and model parameters. Photo-meson interactions also produce neutrinos at energies ranging from sub-TeV to EeV, which will be probed with forthcoming experiments such as IceCube, ANITA and KM3NeT. This would provide information about the fundamental interaction physics, the acceleration mechanism, the nature of the sources and their environment.

scholarly journals Recent Results from the CANGAROO Project

1996 ◽  
Vol 160 ◽  
pp. 363-364
Author(s):  
S.A. Dazeley ◽  
P.G. Edwards ◽  
J.R. Patterson ◽  
G.P. Rowell ◽  
M. Sinnott ◽  
...  
Keyword(s):  
Gamma Rays ◽  
South Australia ◽  
Cosmic Ray ◽  
High Energy ◽  
Relativistic Electrons ◽  
Large Numbers ◽  
Inverse Compton ◽  
Very High Energy ◽  
Large Telescopes ◽  
Very High

TheCollaboration ofAustralia andNippon for aGAmmaRayObservatory in theOutback operates two large telescopes at Woomera (South Australia), which detect the Čerenkov light images produced in the atmosphere by electronpositron cascades initiated by very high energy (~1 TeV or 1012eV) gamma rays. These gamma rays arise from a different mechanism than at EGRET energies: inverse Compton (IC) emission from relativistic electrons.The spoke-like images are recorded by a multi-pixel camera which facilitates the rejection of the large numbers of oblique and ragged cosmic ray images. A field of view ~3.5° is required. The Australian team operates a triple 4 m diameter mirror telescope, BIGRAT, with a 37 photomultiplier tube camera and energy threshold 600 GeV. The Japanese operate a single, highly accurate 3.8 m diameter f/1 telescope and high resolution 256 photomultipler tube camera. In 1998 a new 7 m telescope is planned for Woomera with a design threshold ~;200GeV.

scholarly journals A MODEL-INDEPENDENT METHOD TO STUDY DARK MATTER INDUCED LEPTONS AND GAMMA RAYS

2012 ◽  
Vol 27 (35) ◽  
pp. 1250206 ◽  
Author(s):  
MINGXING LUO ◽  
LIUCHENG WANG ◽  
GUOHUAI ZHU
Keyword(s):  
Dark Matter ◽  
Compton Scattering ◽  
Gamma Rays ◽  
Particle Physics ◽  
Cosmic Ray ◽  
Propagation Model ◽  
Strong Constraint ◽  
Inverse Compton Scattering ◽  
Inverse Compton ◽  
Model Independent

By using recent data, we directly determine the dark matter (DM)-induced e± spectrum at the source from experimental measurements at the earth, without reference to specific particle physics models. The DM-induced gamma rays emitted via inverse Compton scattering are then obtained in a model-independent way. However, the results depend on the choice of the astrophysical e± background, which is not reliably known. Nevertheless, we calculate, as an illustration, the fluxes of gamma rays from the Fornax cluster in the decaying DM scenario with various astrophysical e± backgrounds. Without any assumptions on details of the DM model, the predictions turn out to be either in disagreement with or only marginally below the upper limits measured recently by the Fermi-LAT Collaboration. In addition, these DM-induced ICS gamma rays in the GeV range are shown to be almost independent of choices of cosmic ray propagation model and of DM density profile, when a given astrophysical e± background is assumed. This provides a strong constraint on decaying DM scenario as the gamma rays may be produced in other processes besides inverse Compton scattering, such as the bremsstrahlung and neutral pion decays.

Inverse Compton Gamma Rays from Dark Matter Annihilation in the Dwarf Galaxies

2016 ◽  
Vol 37 (3) ◽  
Author(s):  
Jayashri Medhi ◽  
H. L. Duorah ◽  
A. G. Barua ◽  
K. Duorah
Keyword(s):  
Dark Matter ◽  
Gamma Rays ◽  
Dwarf Galaxies ◽  
Dark Matter Annihilation ◽  
Inverse Compton

scholarly journals LSI +61°303: A Pulsar Wind Nebula in a Binary?

2004 ◽  
Vol 218 ◽  
pp. 219-220
Author(s):  
D. A. Leahy
Keyword(s):  
Radio Emission ◽  
Gamma Rays ◽  
Confining Pressure ◽  
Rapid Expansion ◽  
Photon Flux ◽  
Relativistic Electrons ◽  
X Rays ◽  
X Ray ◽  
Inverse Compton ◽  
Pulsar Wind

LSI +61°303 outbursts are modeled as a pulsar wind nebula expanding inside the environment provided by the Be companion star's stellar wind and photon flux. A set of equations describing the system is developed and solved numerically for representative sets of parameters. Emission in X-rays through gamma-rays is due to inverse Compton emission from relativistic electrons around the pulsar. The radio emission is due to synchrotron emission of varying optical depth, which yields a varying spectral index. The peak of X-ray emission is near periastron and the peak of the radio emission is near apastron, due to reduced confining pressure on the relativistic electron cloud and its subsequent rapid expansion.

scholarly journals Observational signatures of gamma-rays from bright blazars and wakefield theory

2020 ◽  
Vol 493 (2) ◽  
pp. 2229-2237 ◽  
Author(s):  
N E Canac ◽  
K N Abazajian ◽  
T Tajima ◽  
T Ebisuzaki ◽  
S Horiuchi
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Accretion Disc ◽  
Spectral Energy ◽  
Energy Distributions ◽  
Wakefield Acceleration ◽  
Inverse Compton ◽  
Time Variations ◽  
First Time ◽  
Over Time

ABSTRACT Gamma-ray observations have revealed strong variability in blazar luminosities in the gamma-ray band over time-scales as short as minutes. We show, for the first time, that the correlation of the spectrum with intensity is consistent with the behaviour of the luminosity variation of blazar spectral energy distributions (SEDs) along a blazar sequence for low synchrotron peak blazars. We show that the observational signatures of variability with flux are consistent with wakefield acceleration of electrons initiated by instabilities in the blazar accretion disc. This mechanism reproduces the observed time variations as short as 100 s. The wakefield mechanism also predicts a reduction of the electron spectral index with increased gamma-ray luminosity, which could be detected in higher energy observations well above the inverse Compton peak.

Determination of photoneutron cross sections for [sup 197]Au by using laser inverse-Compton scattering gamma-rays

2010 ◽  
Author(s):  
O. Itoh ◽  
H. Utsunomiya ◽  
H. Akimune ◽  
T. Yamagata ◽  
M. Kamata ◽  
...  
Keyword(s):  
Compton Scattering ◽  
Gamma Rays ◽  
Cross Sections ◽  
Inverse Compton Scattering ◽  
Inverse Compton
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