scholarly journals LS I +61 303: MICROQUASAR OR NOT MICROQUASAR?

2008 ◽  
Vol 17 (10) ◽  
pp. 1875-1881
Author(s):  
G. E. ROMERO ◽  
M. ORELLANA ◽  
A. T. OKAZAKI ◽  
S. P. OWOCKI
Keyword(s):  
Neutron Star ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Compact Object ◽  
High Energy ◽  
Very High Energy ◽  
Be Star ◽  
Energy Gamma ◽  
High Energy Emission ◽  
Very High

LS I +61 303 is a puzzling object detected from radio up to very high-energy gamma-rays. Variability has recently been observed in its high-energy emission. The object is a binary system, with a compact object and a Be star as primary. The nature of the secondary and the origin of the gamma-ray emission are not clearly established at present. Recent VLBA radio data have been used to claim that the system is a Be /neutron star colliding wind binary, instead of a microquasar. We review the main views on the nature of LS I +61 303 and present results of 3D SPH simulations that can shed some light on the nature of the system. Our results support an accretion powered source, compatible with a microquasar interpretation.

RESULTS FROM GALACTIC OBSERVATIONS WITH MAGIC

2010 ◽  
Vol 19 (06) ◽  
pp. 1023-1029
Author(s):  
◽  
JAVIER RICO
Keyword(s):  
Gamma Rays ◽  
Energy Band ◽  
Binary Systems ◽  
High Energy ◽  
Cherenkov Telescope ◽  
La Palma ◽  
Very High Energy ◽  
Energy Gamma ◽  
High Energy Emission ◽  
Very High

MAGIC is a single-dish Cherenkov telescope located on La Palma (Spain), hence with an optimal view on the Northern sky. Sensitive to the 30 GeV–30 TeV energy band, it is nowadays the only ground-based instrument being able to measure high-energy gamma-rays below 100 GeV. With the operation in coincidence with MACIC-II, starting in Fall 2009, the sensitivity will be improved by a factor ~ 2. We review the results obtained by MAGIC on the very-high energy emission from pulsars, binary systems and microquasars.

scholarly journals Very High Energy Gamma Rays from Plerions: CANGAROO Results

1998 ◽  
Vol 188 ◽  
pp. 125-128
Author(s):  
T. Kifune
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
High Energy ◽  
Current Status ◽  
Emission Region ◽  
Thermal Processes ◽  
High Energy Gamma ◽  
Very High Energy ◽  
Energy Gamma ◽  
Very High

The current status of very high energy gamma ray astronomy (in ~ 1 TeV region) is described by using as example results of CANGAROO (Collaboration of Australia and Nippon for a GAmma Ray Observatory in the Outback). Gamma rays at TeV energies, emitted through inverse Compton effect of electrons or π0 decay from proton interaction, provide direct evidence on “hot” non-thermal processes of the Universe, as well as environmental features, such as the strength of magnetic field in the emission region, for the non-thermal processes.

scholarly journals TeV J2032+4130 - very high energy gamma-ray source of unresolved nature

2019 ◽  
Vol 208 ◽  
pp. 14009
Author(s):  
V.G. Sinitsyna ◽  
V.Y. Sinitsyna ◽  
K.A. Balygin ◽  
S.S. Borisov ◽  
A.M. Kirichenko ◽  
...  
Keyword(s):  
Supernova Remnants ◽  
Gamma Ray ◽  
High Energy ◽  
Electromagnetic Spectrum ◽  
Object Type ◽  
Very High Energy ◽  
Energy Gamma ◽  
Star Formation Regions ◽  
High Energy Emission ◽  
Very High

The Cygnus Region is one of the brightest regions in all ranges of the electromagnetic spectrum and contains a number of potential GeV and TeV emission sources. It includes active star formation regions, pulsars and supernova remnants. Some of the sources have been detected at high and very high energies. One of them discovered due to its proximity to the well-known microquasar Cyg X-3 is the object TeV J2032+4130. This object is still of unresolved nature and is being intensively studied in different energy ranges. The results of twenty-year observations of TeV J2032+4130 by the SHALON experiment are presented in this paper. The collected experimental data on fluxes, spectrum shape and morphology of TeV J2032+413 can help in the future to determine an object type and reveal mechanisms of generation of very high energy emission.

scholarly journals Very high energy gamma-rays from flat spectrum radio quasars

2014 ◽  
Vol 10 (S313) ◽  
pp. 27-32
Author(s):  
Elina Lindfors
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
High Energy ◽  
High Energy Gamma ◽  
Spectrum Radio ◽  
Very High Energy ◽  
Energy Gamma ◽  
Emission Models ◽  
Γ Rays ◽  
Very High

AbstractThe detection of Flat Spectrum Radio Quasars (FSRQs) in the Very High Energy (VHE, E>100 GeV) range is challenging, mainly because of their steep soft spectra and distance. Nevertheless four FSRQs are now known to be VHE emitters. The detection of the VHE γ-rays has challenged the emission models of these sources. The sources are also found to exhibit very different behavior. I will give an overview of what is known about the VHE emission of these sources and about the multiwavelength signatures that are connected to the VHE gamma-ray emission.

Very high-energy gamma rays from gamma-ray bursts

2007 ◽  
Vol 365 (1854) ◽  
pp. 1343-1356 ◽  
Author(s):  
Paula M Chadwick
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
High Energy ◽  
Gamma Ray Bursts ◽  
Gamma Ray Burst ◽  
Gamma Ray Astronomy ◽  
High Energy Gamma ◽  
Very High Energy ◽  
Energy Gamma ◽  
Very High

Very high-energy (VHE) gamma-ray astronomy has undergone a transformation in the last few years, with telescopes of unprecedented sensitivity having greatly expanded the source catalogue. Such progress makes the detection of a gamma-ray burst at the highest energies much more likely than previously. This paper describes the facilities currently operating and their chances for detecting gamma-ray bursts, and reviews predictions for VHE gamma-ray emission from gamma-ray bursts. Results to date are summarized.

scholarly journals H.E.S.S. observations of RX J1713.7−3946 with improved angular and spectral resolution: Evidence for gamma-ray emission extending beyond the X-ray emitting shell

2018 ◽  
Vol 612 ◽  
pp. A6 ◽  
Author(s):  
◽  
H. Abdalla ◽  
A. Abramowski ◽  
F. Aharonian ◽  
F. Ait Benkhali ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Supernova Remnants ◽  
Gamma Ray ◽  
High Energy ◽  
High Energy Gamma ◽  
The Past ◽  
Very High Energy ◽  
Energy Gamma ◽  
Gamma Ray Emission ◽  
Very High

Supernova remnants exhibit shock fronts (shells) that can accelerate charged particles up to very high energies. In the past decade, measurements of a handful of shell-type supernova remnants in very high-energy gamma rays have provided unique insights into the acceleration process. Among those objects, RX J1713.7−3946 (also known as G347.3−0.5) has the largest surface brightness, allowing us in the past to perform the most comprehensive study of morphology and spatially resolved spectra of any such very high-energy gamma-ray source. Here we present extensive new H.E.S.S. measurements of RX J1713.7−3946, almost doubling the observation time compared to our previous publication. Combined with new improved analysis tools, the previous sensitivity is more than doubled. The H.E.S.S. angular resolution of 0.048° (0.036° above 2 TeV) is unprecedented in gamma-ray astronomy and probes physical scales of 0.8 (0.6) parsec at the remnant’s location. The new H.E.S.S. image of RX J1713.7−3946 allows us to reveal clear morphological differences between X-rays and gamma rays. In particular, for the outer edge of the brightest shell region, we find the first ever indication for particles in the process of leaving the acceleration shock region. By studying the broadband energy spectrum, we furthermore extract properties of the parent particle populations, providing new input to the discussion of the leptonic or hadronic nature of the gamma-ray emission mechanism.

HIGH-ENERGY EMISSION AND ABSORPTION IN CYGNUS X-1

2010 ◽  
Vol 19 (06) ◽  
pp. 763-768
Author(s):  
M. V. DEL VALLE ◽  
M. ORELLANA ◽  
G. E. ROMERO
Keyword(s):  
Soft Power ◽  
Gamma Ray ◽  
Compact Object ◽  
High Energy ◽  
High Mass ◽  
High Energies ◽  
200 Gev ◽  
Very High Energy ◽  
High Energy Emission ◽  
Very High

The high-mass microquasar Cygnus X-1 has been detected during a flaring state at very high energies, E > 200 GeV . The observation was performed by the Atmospheric Cherenkov Telescope MAGIC. It constitutes the first experimental evidence of very-high energy (VHE) emission produced by a Galactic stellar-mass black hole. The observed signal was detected in coincidence with an X–ray flare. The gamma-ray flare occurred when the compact object was located behind the companion star with respect to the line of sight (superior conjunction of the compact object). In this configuration the absorption of VHE photons by annihilation with the stellar photons is expected to be maximum. This suggests that the emission has been originated far above the compact object. The energy spectrum is well fitted by a relatively soft power-law. We present a model for the absorption and the emission of VHE gamma-rays in Cyg X-1. Detailed calculations of the gamma-ray opacity due to pair creation are provided and used to establish constraints on the emitting region. We propose that the high energy flare was the result of the interaction between the jet and a very dense clump from the stellar wind.

The CANGAROO Project: Very High Energy Gamma-ray Astronomy at Woomera

1992 ◽  
Vol 10 (1) ◽  
pp. 27-29 ◽  
Author(s):  
P.G. Edwards ◽  
A.G. Gregory ◽  
J.R. Patterson ◽  
M.D. Roberts ◽  
G.P. Rowell ◽  
...  
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
High Energy ◽  
Gamma Ray Astronomy ◽  
High Energy Gamma ◽  
Very High Energy ◽  
Energy Gamma ◽  
The University ◽  
Very High ◽  
Atmospheric Čerenkov Technique

AbstractIn this paper the Very High Energy (VHE) gamma-ray astronomy program at the University of Adelaide is described. VHE gamma rays with energies above ~5 × 1011eV are observed using the atmospheric Cerenkov technique. Results from the first three years observations at Woomera and the current upgrading of the telecope are described. The CANGAROO project, a collaboration between the University of Adelaide and a number of Japanese institutions, is also introduced.

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