scholarly journals The AGASA and SUGAR Anisotropies and TeV Gamma Rays from the Galactic Center: A Possible Signature of Extremely High Energy Neutrons

2005 ◽  
Vol 622 (2) ◽  
pp. 892-909 ◽  
Author(s):  
Roland M. Crocker ◽  
Marco Fatuzzo ◽  
J. R. Jokipii ◽  
Fulvio Melia ◽  
Raymond R. Volkas
Keyword(s):  
Gamma Rays ◽  
Galactic Center ◽  
High Energy ◽  
Tev Gamma Rays

scholarly journals The jet in M87 from e-EVN observations

2010 ◽  
Vol 6 (S275) ◽  
pp. 150-154 ◽  
Author(s):  
G. Giovannini ◽  
C. Casadio ◽  
M. Giroletti ◽  
M. Beilicke ◽  
A. Cesarini ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Monitoring Program ◽  
High Energy ◽  
Time Range ◽  
Apparent Velocity ◽  
Massive Black Hole ◽  
Open Questions ◽  
Tev Gamma Rays ◽  
5 Ghz ◽  
Clear Change

AbstractOne of the most intriguing open questions of today's astrophysics is the jet physical properties and the location and the mechanisms for the production of MeV, GeV, and TeV gamma-rays in AGN jets. M87 is a privileged laboratory for a detailed study of the properties of jets, owing to its proximity, its massive black hole, and its conspicuous emission at radio wavelengths and above. We started on November 2009 a monitoring program with the e-EVN at 5 GHz. We present here results of these multi-epoch observations and discuss the two episodes of activity at energy E>100 GeV that occured in this period. One of these observations was obtained at the same day of the first high energy flare. We added to our results literature data obtained with the VLBI and VLA. A clear change in the proper motion velocity of HST-1 is present at the epoch ~2005.5. In the time range 1998 – 2005.5 the apparent velocity is subluminal, and superluminal (~2.7c) after 2005.5.

scholarly journals Detection of TeV Gamma Rays from SN1006

1998 ◽  
Vol 188 ◽  
pp. 121-124 ◽  
Author(s):  
Toru Tanimori
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Gamma Rays ◽  
High Energy ◽  
Shock Acceleration ◽  
Emission Region ◽  
X Ray ◽  
High Energy Electrons ◽  
Tev Gamma Rays ◽  
The Magnetic Field

In spite of the recent progress of high energy gamma-ray astronomy, there still remains quite unclear and important problem about the origin of cosmic rays. Supernova remnants (SNRs) are the favoured site for cosmic rays up to 1016 eV, as they satisfy the requirements such as an energy input rate. But direct supporting evidence is sparse. Recently intense non-thermal X-ray emission from the rims of the Type Ia SNR SN1006 (G327.6+14.6) has been observed by ASCA (Koyama et al. 1995)and ROSAT (Willingale et al. 1996), which is considered, by attributing the emission to synchrotron radiation, to be strong evidence of shock acceleration of high energy electrons up to ~100 TeV. If so, TeV gamma rays would also be expected from inverse Compton scattering (IC) of low energy photons (mostly attributable to the 2.7 K cosmic background photons) by these electrons. By assuming the magnetic field strength (B) in the emission region of the SNR, several theorists (Pohl 1996; Mastichiadis 1996; Mastichiadis & de Jager 1996; Yoshida & Yanagita 1997) calculated the expected spectra of TeV gamma rays using the observed radio/X-ray spectra. Observation of TeV gamma rays would thus provide not only the further direct evidence of the existence of very high energy electrons but also the another important information such as the strength of the magnetic field and diffusion coefficient of the shock acceleration. With this motivation, SN1006 was observed by the CANGAROO imaging air Cerenkov telescope in 1996 March and June, also 1997 March and April.

scholarly journals H.E.S.S. searches for TeV gamma-rays associated to high-energy neutrinos

2019 ◽  
Author(s):  
Fabian Schüssler ◽  
H. Ashkar ◽  
M. Backes ◽  
Kathrin Egberts ◽  
F. Brun ◽  
...  
Keyword(s):  
Gamma Rays ◽  
High Energy ◽  
High Energy Neutrinos ◽  
Tev Gamma Rays

scholarly journals VHE GAMMA-RAYS FROM GALACTIC X-RAY BINARY SYSTEMS

2008 ◽  
Vol 17 (10) ◽  
pp. 1849-1858 ◽  
Author(s):  
J. M. PAREDES
Keyword(s):  
Gamma Rays ◽  
Binary Systems ◽  
High Energy ◽  
X Ray ◽  
Very High Energy ◽  
Γ Rays ◽  
Γ Ray ◽  
Tev Gamma Rays ◽  
X Ray Binaries ◽  
Very High

The detection of TeV gamma-rays from LS 5039 and the binary pulsar PSR B1259–63 by HESS, and from LS I +61 303 and the stellar-mass black hole Cygnus X-1 by MAGIC, provides clear evidence of very efficient acceleration of particles to multi-TeV energies in X-ray binaries. These observations demonstrate the richness of nonthermal phenomena in compact galactic objects containing relativistic outflows or winds produced near black holes and neutron stars. I review here some of the main observational results on very high energy (VHE) γ-ray emission from X-ray binaries, as well as some of the proposed scenarios to explain the production of VHE γ-rays. I put special emphasis on the flare TeV emission, suggesting that the flaring activity might be a common phenomena in X-ray binaries.

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