scholarly journals Search for UHE gamma ray sources in the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 337-338
Author(s):  
I. A. Bond
Keyword(s):  
Magnetic Field ◽  
Gamma Ray ◽  
High Energy ◽  
Magellanic Clouds ◽  
Ultra High Energy ◽  
Intergalactic Magnetic Field ◽  
Γ Ray ◽  
Experimental Survey

An experimental survey of ultra-high-energy γ-ray sources in the Magellanic Clouds is described. Results of the survey may be used to study the intergalactic magnetic field.

scholarly journals Gamma-ray counterparts of 2WHSP high-synchrotron-peaked BL Lac objects as possible signatures of ultra-high-energy cosmic ray emission

2020 ◽  
Vol 497 (2) ◽  
pp. 2455-2468
Author(s):  
Michael W Toomey ◽  
Foteini Oikonomou ◽  
Kohta Murase
Keyword(s):  
Energy Range ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Potential Candidate ◽  
Ultra High Energy ◽  
Bl Lac Objects ◽  
Cherenkov Telescopes ◽  
Bl Lac ◽  
Γ Ray

ABSTRACT We present a search for high-energy γ-ray emission from 566 Active Galactic Nuclei at redshift z > 0.2, from the 2WHSP catalogue of high-synchrotron peaked BL Lac objects with 8 yr of Fermi-LAT data. We focus on a redshift range where electromagnetic cascade emission induced by ultra-high-energy cosmic rays can be distinguished from leptonic emission based on the spectral properties of the sources. Our analysis leads to the detection of 160 sources above ≈5σ (TS ≥25) in the 1–300 GeV energy range. By discriminating significant sources based on their γ-ray fluxes, variability properties, and photon index in the Fermi-LAT energy range, and modelling the expected hadronic signal in the TeV regime, we select a list of promising sources as potential candidate ultra-high-energy cosmic ray emitters for follow-up observations by Imaging Atmospheric Cherenkov Telescopes.

scholarly journals Prospect on intergalactic magnetic field measurements with gamma-ray instruments

2012 ◽  
Vol 8 (S294) ◽  
pp. 459-470
Author(s):  
Hélène Sol ◽  
Andreas Zech ◽  
Catherine Boisson ◽  
Henric Krawczynski ◽  
Lisa Fallon ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Gamma Ray ◽  
Field Measurements ◽  
High Energy ◽  
Wide Field ◽  
Extragalactic Background Light ◽  
Spatially Extended ◽  
Very High Energy ◽  
Energy Gamma ◽  
Intergalactic Magnetic Field

AbstractObserving high-energy gamma-rays from Active Galactic Nuclei (AGN) offers a unique potential to probe extremely tiny values of the intergalactic magnetic field (IGMF), a long standing question of astrophysics, astroparticle physics and cosmology. Very high energy (VHE) photons from blazars propagating along the line of sight interact with the extragalactic background light (EBL) and produce e+e− pairs. Through inverse-Compton interaction, mainly on the cosmic microwave background (CMB), these pairs generate secondary GeV-TeV components accompanying the primary VHE signal. Such secondary components would be detected in the gamma-ray range as delayed “pair echos” for very weak IGMF (B < 10−16G), while they should result in a spatially extended gamma-ray emission around the source for higher IGMF values (B > 10−16G). Coordinated observations with space (i.e. Fermi) and ground-based gamma-ray instruments, such as the present Cherenkov experiments H.E.S.S., MAGIC and VERITAS, the future Cherenkov Telescope Array (CTA) Observatory, and the wide-field detectors such as HAWC and LHAASO, should allow to analyze and finally detect such echos, extended emission or pair halos, and to further characterize the IGMF.

Survey of ultra-high-energy gamma-ray emission in the Magellanic Clouds

1993 ◽  
Vol 403 ◽  
pp. 239 ◽  
Author(s):  
W. H. Allen ◽  
I. A. Bond ◽  
E. Budding ◽  
M. J. Conway ◽  
A. Daniel ◽  
...  
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Magellanic Clouds ◽  
Ultra High Energy ◽  
High Energy Gamma ◽  
Energy Gamma ◽  
Gamma Ray Emission

scholarly journals Producing ultra high energy cosmic rays from AGN magnetic luminosity

2016 ◽  
Vol 12 (S324) ◽  
pp. 207-210
Author(s):  
Carlos H. Coimbra-Araújo ◽  
Rita C. Anjos
Keyword(s):  
Cosmic Rays ◽  
Gamma Ray ◽  
Direct Detection ◽  
High Energy ◽  
Alternative Methods ◽  
Ultra High Energy ◽  
High Energy Cosmic Rays ◽  
Lack Of Information ◽  
Upper Limits ◽  
Intergalactic Magnetic Field

AbstractThe present work proposes a method to calculate the AGN magnetic luminosity fraction to be converted into ultra high energy cosmic rays (UHECRs) luminosities for nine UHECR AGN Seyfert sources based on the respective observation of gamma ray upper limits. The motivation for such calculation comes attached to the fact that a fraction of the magnetic luminosity (LB) produced by Kerr black holes in some AGNs can produce the necessary energy to accelerate UHECRs beyond the GZK limit, observed, e.g., by the Auger experiment. Nevertheless, the direct detection of those UHECRs has a lack of information about the direction of the source from where those cosmic rays are coming, since charged particles are deflected by the intergalactic magnetic field. Such problem arises alternative methods to evaluate the luminosity of UHECRs from the observation of upper limits during the propagation.

DETECTING GAMMA-RAY BURSTS WITH ULTRA-HIGH ENERGY NEUTRINOS

2005 ◽  
Vol 20 (14) ◽  
pp. 3099-3101 ◽  
Author(s):  
SOEBUR RAZZAQUE ◽  
PETER MÉSZÁROS ◽  
ELI WAXMAN
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Gamma Ray ◽  
High Energy ◽  
Gamma Ray Bursts ◽  
Ultra High Energy ◽  
Ultrahigh Energy ◽  
Radiation Mechanism ◽  
High Energy Cosmic Rays ◽  
Ice Cube

Gamma-ray bursts are candidate sources of ultra-high energy cosmic rays and neutrinos. While cosmic rays are scattered in the intervening magnetic field, neutrinos point back to their sources being charge neutral and make neutrino astronomy possible. Detection of ultrahigh energy neutrinos by future experiments such as ANITA, ANTARES, Ice-Cube and RICE can provide useful information such as particle acceleration, radiation mechanism and magnetic field about the sources and their progenitors. Detection of ultrahigh energy neutrinos which point back to their sources may establish gamma-ray bursts as the sources of GZK cosmic rays.

scholarly journals Ultra-high-energy cosmic rays in the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 432-433
Author(s):  
R. J. Protheroe
Keyword(s):  
Synchrotron Radiation ◽  
High Energy ◽  
Magellanic Clouds ◽  
Ultra High Energy ◽  
Microwave Background ◽  
X Ray ◽  
High Energy Cosmic Rays ◽  
Γ Rays ◽  
Γ Ray ◽  
X Ray Binaries

Ultra-high-energy (UHE) γ-rays have been detected from several X-ray binaries. UHE γ-rays from sources in the LMC will interact in the microwave background producing electrons which emit synchrotron radiation in the X-ray and γ-ray bands. This radiation might be observable.

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