scholarly journals Very high energy γ-radiation from the radio quasar 4C 21.35

2011 ◽  
Vol 7 (S284) ◽  
pp. 414-416
Author(s):  
Josefa Becerra González ◽  
Laura Maraschi ◽  
Daniel Mazin ◽  
Elisa Prandini ◽  
Koji Saito ◽  
...  
Keyword(s):  
High Energy ◽  
Γ Radiation ◽  
Cherenkov Telescopes ◽  
Spectrum Radio ◽  
Hard Spectrum ◽  
Very High Energy ◽  
Γ Rays ◽  
Radio Quasar ◽  
Fast Variation ◽  
Very High

AbstractA very high energy (VHE) γ-radiation was detected from a flat spectrum radio quasar (FSRQ) 4C 21.35 (PKS1222+21) by MAGIC (Major Atmospheric Gamma Imaging Cherenkov) telescopes on June 17th 2010. 4C 21.35 is only the 3rd FSRQ detected in VHE γ-rays. With its hard spectrum (Γ = 2.72±0.34) with no apparent cut-off at energies below 130 GeV and an extremely fast variation of flux (doubling in 8.6+1.1−0.9 minutes), this detection poses a challenge to existing models of VHE γ-radiation from FSRQs. The most important results of observations performed by MAGIC telescopes are presented here, as well as some possible explanations of those results.

scholarly journals THE H.E.S.S. EXTRAGALACTIC SKY

2014 ◽  
Vol 28 ◽  
pp. 1460163
Author(s):  
◽  
JEAN-PHILIPPE LENAIN
Keyword(s):  
Radio Galaxies ◽  
High Energy ◽  
Bl Lac Objects ◽  
Dominant Class ◽  
Cherenkov Telescopes ◽  
Spectrum Radio ◽  
System Experiment ◽  
Very High Energy ◽  
Stereoscopic System ◽  
Very High

More than fifty extragalactic very high energy (VHE; E > 100 GeV) sources have been found using ground-based imaging atmospheric Cherenkov telescopes, about twenty of which have been discovered using the H.E.S.S. (High Energy Stereoscopic System) experiment based in Namibia. Even though BL Lac objects are the dominant class of VHE detected extragalactic objects, other types of sources (starburst galaxies, radio galaxies or flat spectrum radio quasars) begin to emerge. A review of the extragalactic sources studied with H.E.S.S. is given, with an emphasis on new results.

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.

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 Search for High Energy emission from GRBs with MAGIC

2016 ◽  
Vol 12 (S324) ◽  
pp. 70-73
Author(s):  
Alessio Berti ◽  
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Cherenkov Telescopes ◽  
Gamma Ray Imaging ◽  
Very High Energy ◽  
Γ Rays ◽  
High Energy Emission ◽  
The Universe ◽  
Very High

AbstractGamma-Ray Bursts (GRBs) are the most violent explosions in the Universe, releasing a huge amount of energy in few seconds. While our understanding of the prompt and the afterglow phases has increased with Swift and Fermi, we have very few information about their High Energy (HE, E ≲ 100) emission components. This requires a ground-based experiment able to perform fast follow-up with enough sensitivity above ~ 50 GeV. The MAGIC (Major Atmospheric Gamma-ray Imaging Cherenkov) telescopes have been designed to perform fast follow-up on GRBs thanks to fast slewing movement and low energy threshold (~ 50 GeV). Since the beginning of the operations, MAGIC followed-up 89 GRBs in good observational conditions. In this contribution the MAGIC GRBs follow-up campaign and the results which could be obtained by detecting HE and Very High Energy (VHE, E ≳ 100 GeV) γ-rays from GRBs will be reviewed.

scholarly journals The VHE γ-Ray View of the FSRQ PKS 1510-089

Galaxies ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 41 ◽  
Author(s):  
Michael Zacharias ◽  
Dijana Dominis Prester ◽  
Felix Jankowsky ◽  
Elina Lindfors ◽  
Manuel Meyer ◽  
...  
Keyword(s):  
High Energy ◽  
High Variability ◽  
Energy Bands ◽  
Current State ◽  
Spectrum Radio ◽  
Very High Energy ◽  
Monitoring Effort ◽  
Γ Ray ◽  
Radio Quasar ◽  
Very High

The flat spectrum radio quasar PKS 1510-089 is a monitored target in many wavelength bands due to its high variability. It was detected as a very-high-energy (VHE) γ-ray emitter with H.E.S.S. in 2009, and has since been a regular target of VHE observations by the imaging Cherenkov observatories H.E.S.S. and MAGIC. In this paper, we summarize the current state of results focusing on the monitoring effort with H.E.S.S. and the discovery of a particularly strong VHE flare in 2016 with H.E.S.S. and MAGIC. While the source has now been established as a weak, but regular emitter at VHE, no correlation with other energy bands has been established. This is underlined by the 2016 VHE flare, where the detected optical and high-energy γ-ray counterparts evolve differently than the VHE flux.

scholarly journals PKS 1510-089: a rare example of a flat spectrum radio quasar with a very high-energy emission

2014 ◽  
Vol 567 ◽  
pp. A113 ◽  
Author(s):  
Anna Barnacka ◽  
Rafal Moderski ◽  
Bagmeet Behera ◽  
Pierre Brun ◽  
Stefan Wagner
Keyword(s):  
High Energy ◽  
Energy Emission ◽  
Spectrum Radio ◽  
Very High Energy ◽  
High Energy Emission ◽  
Radio Quasar ◽  
Very High

The origin of HE and VHE gamma-ray flares from FSRQs

2018 ◽  
Vol 27 (10) ◽  
pp. 1844007
Author(s):  
S. Gasparyan ◽  
N. Sahakyan ◽  
P. Chardonnet
Keyword(s):  
Energy Distribution ◽  
Gamma Ray ◽  
Spectral Energy Distribution ◽  
High Energy ◽  
Spectral Energy ◽  
Cherenkov Telescopes ◽  
Spectrum Radio ◽  
Very High Energy ◽  
Energy Gamma ◽  
Very High

The discovery of very-high-energy gamma-ray emission from Flat Spectrum Radio Quasars (FSRQs) by ground-based Cherenkov telescopes (HESS, MAGIC, VERITAS) provides a new view of blazar emission processes. The available data from multiwavelength observations of FSRQs, allow us to constrain the size (possibly also location) of the emitting region, magnetic field, electron energy distribution, etc., which are crucial for the understanding of the jet properties. We investigate the origin of emission from FSRQs (PKS 1510-089, PKS 1222+216 and 3C 279) by modeling the broadband spectral energy distribution in their quiescent and flaring states, using estimation of the parameter space that describes the underlying particle distribution responsible for the emission through the Markov Chain Monte Carlo (MCMC) technique.

scholarly journals Multiwavelength observations in 2019-2020 of a new very-high-energy gamma-ray emitter: the flat spectrum radio quasar QSO B1420+326

2021 ◽  
Author(s):  
Filippo D’Ammando ◽  
Roberto Angioni ◽  
Monica Orienti ◽  
Julian Sitarek ◽  
Seiya Nozaki ◽  
...  
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
High Energy Gamma ◽  
Spectrum Radio ◽  
Very High Energy ◽  
Energy Gamma ◽  
Radio Quasar ◽  
Very High ◽  
Multiwavelength Observations

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.

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