Very High Energy γ-rays from AGN

2002 ◽  
Vol 19 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Tadashi Kifune
Keyword(s):  
Electromagnetic Radiation ◽  
Active Galactic Nuclei ◽  
Energy Band ◽  
Galactic Nuclei ◽  
High Energy ◽  
Current Status ◽  
Very High Energy ◽  
Γ Rays ◽  
Γ Ray ◽  
Very High

AbstractEvidence of TeV γ-ray emission has been found for only a handful of active galactic nuclei, with detailed investigations limited to the blazars Mrk 421 and Mrk 501. TeV γ-ray astronomy, as the highest energy band, provides important information that is hard to obtain from longer wavelength electromagnetic radiation. The current status of TeV γ-ray studies of active galactic nuclei is summarized and our understanding of the high energy phenomena taking place in active galactic nuclei is outlined, with the prospects for future TeV γ-ray observations also considered.

Very high energy γ rays from close active galactic nuclei Mkn 421, Mkn 501, and NGC 1275

2007 ◽  
Vol 71 (7) ◽  
pp. 906-909 ◽  
Author(s):  
V. G. Sinitsina ◽  
T. P. Arsov ◽  
S. S. Borisov ◽  
S. I. Nikol’sky ◽  
F. I. Musin ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
High Energy ◽  
Very High Energy ◽  
Γ Rays ◽  
Ngc 1275 ◽  
Very High

scholarly journals Massive stars at (very) high energies: γ-ray binaries

2010 ◽  
Vol 6 (S272) ◽  
pp. 581-586
Author(s):  
Guillaume Dubus ◽  
Benoît Cerutti
Keyword(s):  
High Energy Physics ◽  
Thermal Emission ◽  
Compact Object ◽  
High Energy ◽  
Be Stars ◽  
Radiative Power ◽  
Very High Energy ◽  
Γ Rays ◽  
Γ Ray ◽  
Very High

Abstractγ-ray binaries are systems that emit most of their radiative power above 1 MeV. They are associated with O or Be stars in orbit with a compact object, possibly a young pulsar. Much like colliding wind binaries, the pulsar generates a relativistic wind that interacts with the stellar wind. The result is non-thermal emission from radio to very high energy γ-rays. The wind, radiation and magnetic field of the massive star play a major role in the dynamics and radiative output of the system. They are particularly important to understand the high energy physics at work. Inversely, γ-ray binaries offer novel probes of stellar winds and insights into the fate of O/B binaries.

scholarly journals OBSERVATIONS OF MICROQUASAR CANDIDATES WITH THE MAGIC TELESCOPE

2008 ◽  
Vol 17 (10) ◽  
pp. 1859-1866
Author(s):  
◽  
J. RICO
Keyword(s):  
Black Hole ◽  
Experimental Evidence ◽  
Energy Band ◽  
High Energy ◽  
Time Dependent ◽  
X Ray ◽  
Orbital Cycles ◽  
Very High Energy ◽  
Γ Ray ◽  
Very High

We report on the results from the observations in very high energy band (VHE, Eγ ≥ 100 GeV ) of the γ-ray binary LS I +61 303 and the black hole X-ray binary (BHXB) Cygnus X-1. LS I +61 303 was recently discovered at VHE by MAGIC1 and here we present the preliminary results from an extensive observation campaign, comprising 112 observation hours covering 4 orbital cycles, aiming at determining the time-dependent features of the VHE emission. Cygnus X-1 was observed for a total of 40 hours during 26 nights, spanning the period between June and November 2006. We report on the results of the searches for steady and variable γ-ray signals from Cygnus X-1, including the first experimental evidence for an intense flare, of duration between 1.5 and 24 hours.

scholarly journals OBSERVATION OF GALACTIC SOURCES OF VERY HIGH ENERGY γ-RAYS WITH THE MAGIC TELESCOPE

2007 ◽  
Vol 22 (29) ◽  
pp. 2167-2174
Author(s):  
H. BARTKO
Keyword(s):  
Supernova Remnants ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
High Energy ◽  
Γ Radiation ◽  
La Palma ◽  
Very High Energy ◽  
Γ Rays ◽  
Galactic Sources ◽  
Very High

The MAGIC telescope with its 17m diameter mirror is today the largest operating single-dish Imaging Air Cherenkov Telescope (IACT). It is located on the Canary Island La Palma, at an altitude of 2200 m above sea level, as part of the Roque de los Muchachos European Northern Observatory. The MAGIC telescope detects celestial very high energy γ-radiation in the energy band between about 50 GeV and 10 TeV. Since the autumn of 2004 MAGIC has been taking data routinely, observing various objects, like supernova remnants (SNRs), γ-ray binaries, Pulsars, Active Galactic Nuclei (AGN) and Gamma-ray Bursts (GRB). We briefly describe the observational strategy, the procedure implemented for the data analysis, and discuss the results of observations of Galactic Sources.

scholarly journals Similarity and diversity of black holes - view from the Very High Energies

2016 ◽  
Vol 12 (S324) ◽  
pp. 11-18
Author(s):  
Elina Lindfors
Keyword(s):  
Black Holes ◽  
Active Galactic Nuclei ◽  
Gamma Ray ◽  
Galactic Nuclei ◽  
High Energy ◽  
Mass Scale ◽  
Relativistic Jets ◽  
Very High Energy ◽  
Energy Gamma ◽  
Very High

AbstractActive galactic nuclei, hosting supermassive black holes and launching relativistic jets, are the most numerous objects on the gamma-ray sky. At the other end of the mass scale, phenomena related to stellar mass black holes, in particular gamma-ray bursts and microquasars, are also seen on the gamma-ray sky. While all of them are thought to launch relativistic jets, the diversity even within each of these classes is enormous. In this review, I will discuss recent very high energy gamma-ray results that underline both the similarity of the black hole systems, as well as their diversity.

scholarly journals SSC SCENARIO FOR TEV EMISSION FROM NON-BLAZAR AGNs

2008 ◽  
Vol 17 (09) ◽  
pp. 1577-1584
Author(s):  
J.-P. LENAIN ◽  
C. BOISSON ◽  
H. SOL
Keyword(s):  
Active Galactic Nuclei ◽  
Large Scale ◽  
Galactic Nuclei ◽  
High Energy ◽  
Jet Formation ◽  
Extragalactic Source ◽  
Very High Energy ◽  
Magnetohydrodynamic Simulations ◽  
High Energy Emission ◽  
Very High

M 87 is the first extragalactic source detected in the TeV γ-ray domain that is not a blazar, its large scale jet not being aligned to the line of sight. We present here a multi-blob synchrotron self-Compton model accounting explicitly for large viewing angles and moderate Lorentz factors as inferred from magnetohydrodynamic simulations of jet formation, motivated by the detection of M 87 at very high energies (VHE; E > 100 GeV ). Predictions are presented for the very high-energy emission of active galactic nuclei with extended optical or X-ray jet, which could be misaligned blazars but still show some moderate beaming. We include predictions for 3C 273, Cen A and PKS 0521–36.

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.

scholarly journals A strong radio brightening at the jet base of M87 during the elevated very-high-energy γ-ray state in 2012

2014 ◽  
Vol 10 (S313) ◽  
pp. 340-345
Author(s):  
K. Hada ◽  
M. Giroletti ◽  
M. Kino ◽  
G. Giovannini ◽  
F. D' Ammando ◽  
...  
Keyword(s):  
Radio Galaxy ◽  
High Energy ◽  
Jet Formation ◽  
Radio Monitoring ◽  
Linear Resolution ◽  
Very High Energy ◽  
Γ Rays ◽  
Γ Ray ◽  
Flux Increase ◽  
Very High

AbstractThe nearby radio galaxy M87 offers a unique opportunity for exploring the connection between γ-ray production and jet formation at an unprecedented linear resolution. However, the origin and location of the γ-rays in this source is still elusive. Based on previous radio/TeV correlation events, the unresolved jet base (radio core) and the peculiar knot HST-1 at >120 pc from the nucleus are proposed as candidate site(s) of γ-ray production. Here we report our intensive, high-resolution radio monitoring observations of the M87 jet with the VLBI Exploration of Radio Astrometry (VERA) and the European VLBI Network (EVN) from February 2011 to October 2012. During this period, an elevated level of the M87 flux is reported at TeV with VERITAS. We detected a remarkable flux increase in the radio core with VERA at 22/43 GHz coincident with the VHE activity. Meanwhile, HST-1 remained quiescent in terms of its flux density and structure at radio. These results strongly suggest that the TeV γ-ray activity in 2012 originates in the jet base within 0.03 pc (projected) from the central supermassive black hole.

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