Variations in X rays and very-high-energy γ rays from the blazar Mkn-421 in 2002–2004

2007 ◽  
Vol 71 (7) ◽  
pp. 910-912
Author(s):  
V. V. Fidelis
Keyword(s):  
High Energy ◽  
X Rays ◽  
Very High Energy ◽  
Γ Rays ◽  
Very High

scholarly journals Low frequency radio counterparts of HESS J1731−347 a.k.a SNR G353.6−0.7

2017 ◽  
Vol 12 (S331) ◽  
pp. 201-205
Author(s):  
A. J. Nayana ◽  
Poonam Chandra
Keyword(s):  
Radio Emission ◽  
Radio Telescope ◽  
Supernova Remnants ◽  
Low Frequency ◽  
High Energy ◽  
Spectral Indices ◽  
Thermal Radio Emission ◽  
Very High Energy ◽  
Γ Rays ◽  
Very High

AbstractHESS J1731−347 a.k.a. SNR G353.6−0.7 is one of the five known very high energy (VHE, Energy > 0.1 TeV) shell-type supernova remnants. We carried out Giant Metrewave Radio Telescope (GMRT) observations of this TeV SNR in 1390, 610 and 325 MHz bands. We detected the 325 and 610 MHz radio counterparts of the SNR G353.6−0.7 (Nayana et al. 2017). We also determined the spectral indices of individual filaments and our values are consistent with the non-thermal radio emission. We compared the radio morphology with that of VHE emission. The peak in radio emission corresponds to the faintest feature in the VHE emission. We explain this anti-correlated emission in a possible leptonic origin of the VHE γ-rays.

High-energy resolution in X-ray scattering with the spectrometer INELAX. I. The principles and the test instrument

1991 ◽  
Vol 24 (6) ◽  
pp. 1042-1050 ◽  
Author(s):  
E. Burkel ◽  
B. Dorner ◽  
Th. Illini ◽  
J. Peisl
Keyword(s):  
Energy Resolution ◽  
High Energy ◽  
Bragg Angle ◽  
High Energy Resolution ◽  
X Rays ◽  
Test Results ◽  
X Ray Scattering ◽  
Radiation Sources ◽  
Very High Energy ◽  
Very High

Very high-energy resolution measurements using X-rays can be achieved by extreme backreflection (Bragg angle close to 90°) from perfect crystals. This technique, combined with the high intensity of X-rays emitted by synchrotron-radiation sources, allowed the development of the instrument INELAX for inelastic scattering experiments. The principles and test results are discussed.

scholarly journals Monitoring of the radio galaxy M 87 at Very High Energy with MAGIC during a low emission state between 2012 and 2015

2016 ◽  
Vol 12 (S324) ◽  
pp. 164-167
Author(s):  
C. Arcaro ◽  
P. Bangale ◽  
M. Manganaro ◽  
D. Mazin ◽  
P. Colin ◽  
...  
Keyword(s):  
Radio Galaxy ◽  
Spectral Energy Distribution ◽  
Photon Emission ◽  
High Energy ◽  
Spectral Energy ◽  
X Rays ◽  
Low Emission ◽  
Very High Energy ◽  
Alternative Scenarios ◽  
Very High

AbstractWe present the preliminary results from observing the nearby radio galaxy M 87 for 156 hours (between the years 2012 and 2015) with the MAGIC telescopes, which lead to a significant very high energy (VHE, E > 100 GeV) detection of the source in quiescent states each year. Our VHE analysis combined with quasi-simultaneous data at other energies (from gamma-rays, X-rays, optical and radio) provides a unique opportunity to study the source variability and its broadband spectral energy distribution, which is found to disfavour a one-zone synchrotron/synchrotron self-Compton model. Therefore, other alternative scenarios for the photon emission are explored. We also find that the VHE emission is compatible with being produced close to the source radio core as previous data already indicated. A detailed paper presenting full results of the observing campaign is in preparation.

scholarly journals Very High Energy γ-Ray Generation Near The Light Cylinder of an Axisymmetric Rotator: Cos-B Like γ-Ray Sources

1992 ◽  
Vol 128 ◽  
pp. 207-208
Author(s):  
S. V. Bogovalov ◽  
YU. D. Kotov
Keyword(s):  
High Energy ◽  
Relativistic Electrons ◽  
X Rays ◽  
Inverse Compton Scattering ◽  
Light Cylinder ◽  
Radiation Spectra ◽  
Inverse Compton ◽  
Very High Energy ◽  
Γ Ray ◽  
Very High

AbstractSuper-hard γ-ray radiation spectra have been calculated. This radiation is generated near the velocity-of-light cylinder through the process of inverse-Compton scattering of relativistic electrons by thermal photons radiated by a neutron star. These calculations have been compared with observations of the Crab and Vela pulsars at 1000-GeV γ-ray energies. A correlation between γ-ray flares and those in soft (Ex ≃ lkeV) X-rays are predicted.

scholarly journals High Energy γ-Rays from the Direction of the Crab Pulsar

1981 ◽  
Vol 94 ◽  
pp. 327-328
Author(s):  
T. Dzikowski ◽  
B. Grochalska ◽  
J. Gawin ◽  
J. Wdowczyk
Keyword(s):  
High Energy ◽  
Crab Pulsar ◽  
Muon Detector ◽  
Extensive Air Shower ◽  
Air Shower ◽  
Very High Energy ◽  
Γ Rays ◽  
Shower Array ◽  
Very High ◽  
Air Shower Array

A search has been made for very high energy photons from the direction of the Crab Pulsar using the Lodz extensive air shower array. This device is particularly suitable for such a study because it consists of a large muon detector which can be used to search for the characteristic muon poor showers.

scholarly journals A New Chapter in Hard X-rays of the M87 AGN

Proceedings ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 9
Author(s):  
Ka-Wah Wong ◽  
Rodrigo S. Nemmen ◽  
Jimmy A. Irwin ◽  
Dacheng Lin
Keyword(s):  
High Energy ◽  
X Rays ◽  
X Ray ◽  
Accretion Flow ◽  
Relativistic Jet ◽  
Very High Energy ◽  
Γ Ray ◽  
High Energy Emission ◽  
First Time ◽  
Very High

The nearby M87 hosts an exceptional relativistic jet. It has been regularly monitored in radio to TeV bands, but little has been done in hard X-rays ≳10 keV. For the first time, we have successfully detected hard X-rays up to 40 keV from its X-ray core with joint Chandra and NuSTAR observations, providing important insights to the X-ray origins: from the unresolved jet or the accretion flow. We found that the hard X-ray emission is significantly lower than that predicted by synchrotron self-Compton models introduced to explain very-high-energy γ -ray emission above a GeV. We discuss recent models to understand these high energy emission processes.

A Blind Search for Transient Bursts of Very High Energy γ Rays With Milagro

2008 ◽  
Author(s):  
Vlasios Vasileiou ◽  
M. Galassi ◽  
David Palmer ◽  
Ed Fenimore ◽  
Keyword(s):  
High Energy ◽  
Very High Energy ◽  
Γ Rays ◽  
Blind Search ◽  
Very High

Very high energy y-rays from Cygnus X-3

1981 ◽  
Vol 301 (1462) ◽  
pp. 633-634 ◽  
Keyword(s):  
Light Curve ◽  
High Energy ◽  
Crimean Astrophysical Observatory ◽  
Sharp Peak ◽  
X Rays ◽  
Very High Energy ◽  
Time Variations ◽  
Comparison Of The Results ◽  
Very High

Very high energy y-rays (above 10 12 eV) from Cyg X-3 have been observed for 7 years at the Crimean Astrophysical Observatory by means of the Cherenkov technique. These observations enable us to find the derivative with time of the 4.8 hour periodicity. As is well known, the observations of X -rays have revealed time variations of the Cyg X-3 period (see, for instance, Eisner et al. 1979). The ‘light’ curve for very high energy y-rays has a sharp peak lasting 15 minutes and differs significantly from the ‘light’ curve for X-rays. For this reason the comparison of the results in these two regions is important.

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