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.

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 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.

scholarly journals A fast, very-high-energy γ-ray flare from BL Lacertae during a period of multi-wavelength activity in June 2015

2019 ◽  
Vol 623 ◽  
pp. A175 ◽  
Author(s):  
◽  
V. A. Acciari ◽  
S. Ansoldi ◽  
L. A. Antonelli ◽  
A. Arbet Engels ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Interaction Model ◽  
High Energy ◽  
Spectral Energy ◽  
Polarization Angle ◽  
X Rays ◽  
Bl Lacertae ◽  
Multi Wavelength ◽  
Very High Energy ◽  
Very High

The mechanisms producing fast variability of the γ-ray emission in active galactic nuclei (AGNs) are under debate. The MAGIC telescopes detected a fast, very-high-energy (VHE, E  >  100 GeV) γ-ray flare from BL Lacertae on 2015 June 15. The flare had a maximum flux of (1.5 ± 0.3) × 10−10 photons cm−2 s−1 and halving time of 26 ± 8 min. The MAGIC observations were triggered by a high state in the optical and high-energy (HE, E  >  100 MeV) γ-ray bands. In this paper we present the MAGIC VHE γ-ray data together with multi-wavelength data from radio, optical, X-rays, and HE γ rays from 2015 May 1 to July 31. Well-sampled multi-wavelength data allow us to study the variability in detail and compare it to the other epochs when fast, VHE γ-ray flares have been detected from this source. Interestingly, we find that the behaviour in radio, optical, X-rays, and HE γ-rays is very similar to two other observed VHE γ-ray flares. In particular, also during this flare there was an indication of rotation of the optical polarization angle and of activity at the 43 GHz core. These repeating patterns indicate a connection between the three events. We also test modelling of the spectral energy distribution based on constraints from the light curves and VLBA observations, with two different geometrical setups of two-zone inverse Compton models. In addition we model the γ-ray data with the star-jet interaction model. We find that all of the tested emission models are compatible with the fast VHE γ-ray flare, but all have some tension with the multi-wavelength observations.

Fano Factor Determination For CZT

1997 ◽  
Vol 487 ◽  
Author(s):  
R. H. Redus ◽  
J. A. Pantazis ◽  
A. C. Huber ◽  
V. T. Jordanov ◽  
J. F. Butler ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Fano Factor ◽  
High Energy ◽  
High Resolution Spectroscopy ◽  
High Energy Resolution ◽  
X Rays ◽  
A Value ◽  
Very High Energy ◽  
Gamma Ray Detector ◽  
Very High

AbstractContinued improvements in the manufacturing of Cd1−xZnxTe (CZT) material have resulted in a practical thermoelectrically cooled X-ray and gamma-ray detector of very high energy resolution. A high resolution spectroscopy system was used to measure the Fano factor in CZT at temperatures down to -40°C. The best resolution of the 5.9 keV 55Fe peak was measured to be 188 eV FWHM, while the best resolution of the 59.5 keV 241Am peak was measured to be 482 eV FWHM. The minimum measured Fano factor was 0.082, with several measurements yielding a value of 0.089±0.005. With a resolution of 4.2 keV FWHM for the 662 keV peak of 137Cs, these detectors demonstrate excellent performance in detecting X-rays and gamma rays.

Variability in the light curve of very high energy gamma rays from Cygnus X-3

1985 ◽  
Vol 296 ◽  
pp. 185 ◽  
Author(s):  
M. F. Cawley ◽  
D. J. Fegan ◽  
K. Gibbs ◽  
P. W. Gorham ◽  
R. C. Lamb ◽  
...  
Keyword(s):  
Light Curve ◽  
Gamma Rays ◽  
High Energy ◽  
High Energy Gamma ◽  
Very High Energy ◽  
Energy Gamma ◽  
Very High
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