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.

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 Cygnus X-3 and Other Ultra-High-Energy γ-Ray Sources

1987 ◽  
Vol 125 ◽  
pp. 521-533
Author(s):  
John J. Barnard
Keyword(s):  
Theoretical Models ◽  
High Energy ◽  
Current Status ◽  
Ultra High Energy ◽  
X Ray ◽  
Air Shower ◽  
Γ Rays ◽  
Γ Ray ◽  
High Energy Particles

Recently, several binary X-ray sources have been found to be sources of ultra high energy γ-ray emission. Air shower observations indicate photon energies >∼ 1015 eV. We review the current status of observations from the source Cygnus X-3, and compare this data with that from the sources Hercules X-1, Vela X-1, and LMC X-4. Current theoretical models for the production of γ-rays and the acceleration of high energy particles are discussed and the consequences for the evolution of such systems are examined.

scholarly journals Multimessenger observations of counterparts to IceCube-190331A

2020 ◽  
Vol 497 (3) ◽  
pp. 2553-2561
Author(s):  
Felicia Krauß ◽  
Emily Calamari ◽  
Azadeh Keivani ◽  
Alexis Coleiro ◽  
Phil A Evans ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
High Energy ◽  
Spectral Energy ◽  
Ultra High Energy ◽  
X Ray ◽  
High Energy Cosmic Rays ◽  
High Energies ◽  
Neutrino Event ◽  
Promising Tool ◽  
Localization Region

ABSTRACT High-energy neutrinos are a promising tool for identifying astrophysical sources of high and ultra-high energy cosmic rays (UHECRs). Prospects of detecting neutrinos at high energies (≳TeV) from blazars have been boosted after the recent association of IceCube-170922A and TXS 0506+056. We investigate the high-energy neutrino, IceCube-190331A, a high-energy starting event (HESE) with a high likelihood of being astrophysical in origin. We initiated a Swift/XRT and UVOT tiling mosaic of the neutrino localization and followed up with ATCA radio observations, compiling a multiwavelength spectral energy distribution (SED) for the most likely source of origin. NuSTAR observations of the neutrino location and a nearby X-ray source were also performed. We find two promising counterpart in the 90 per cent confidence localization region and identify the brightest as the most likely counterpart. However, no Fermi/LAT γ-ray source and no prompt Swift/BAT source is consistent with the neutrino event. At this point, it is unclear whether any of the counterparts produced IceCube-190331A. We note that the Helix Nebula is also consistent with the position of the neutrino event and we calculate that associated particle acceleration processes cannot produce the required energies to generate a high-energy HESE neutrino.

scholarly journals The X-ray stellar population of the LMC

2008 ◽  
Vol 4 (S256) ◽  
pp. 20-29 ◽  
Author(s):  
Yaël Nazé
Keyword(s):  
Stellar Population ◽  
Main Sequence ◽  
Massive Stars ◽  
High Energy ◽  
Magellanic Clouds ◽  
X Rays ◽  
X Ray ◽  
Energy Domain ◽  
X Ray Binaries

AbstractIn the study of stars, the high energy domain occupies a place of choice, since it is the only one able to directly probe the most violent phenomena: indeed, young pre-main sequence objects, hot massive stars, or X-ray binaries are best revealed in X-rays. However, previously available X-ray observatories often provided only crude information on individual objects in the Magellanic Clouds. The advent of the highly efficient X-ray facilities XMM-Newton and Chandra has now dramatically increased the sensitivity and the spatial resolution available to X-ray astronomers, thus enabling a fairly easy determination of the properties of individual sources in the LMC.

scholarly journals Stars at γ-Ray Energies: the INTEGRAL Look at Stars

2004 ◽  
Vol 219 ◽  
pp. 55-62
Author(s):  
Thierry Montmerle
Keyword(s):  
Massive Stars ◽  
High Energy ◽  
Energy Sources ◽  
Late Type ◽  
X Ray ◽  
Γ Ray ◽  
October 17 ◽  
X Ray Binaries ◽  
Observational Program

The European γ-ray satellite INTEGRAL, launched on October 17, 2002, is the successor to the highly successful American satellite Compton-GRO. Even though its main observational program focuses on “classical” high-energy sources like compact X-ray binaries or AGNs, some time is being devoted to γ-ray studies of massive stars and magnetically active late-type stars. We briefly describe here the four instruments of INTEGRAL, and summarize the ongoing stellar programs.

scholarly journals ULTRA HIGH ENERGY COSMIC RAYS: PROPAGATION IN THE GALAXY AND ANISOTROPY

2001 ◽  
Vol 16 (39) ◽  
pp. 2505-2515 ◽  
Author(s):  
O. E. KALASHEV ◽  
V. A. KUZMIN ◽  
D. V. SEMIKOZ
Keyword(s):  
Cosmic Rays ◽  
Cold Dark Matter ◽  
High Energy ◽  
Ultra High Energy ◽  
Galactic Magnetic Field ◽  
High Energy Cosmic Rays ◽  
Self Consistent ◽  
The Galaxy ◽  
Γ Ray ◽  
Electron And Photon

We considered propagation of Ultra High Energy Cosmic Rays (UHECR) through the galaxy. We investigated models with sources of UHECR distributed in the same way as Cold Dark Matter (CDM) in a self-consistent way, taking into account both extra-galactic and Galactic contributions. Using a very simple toy model of galactic magnetic field we showed that in the case of galactic origin of UHECRs the anisotropy can reach considerable values. In the case of extragalactic UHECRs origin, the anisotropy appears to be nonvanishing only for electron and photon components due to synchrotron losses, but it can hardly be reassured. The reason is an extremely low flux of UHE electrons and a too low level of γ-ray anisotropy.

Young radio sources at high-energies and the γ-ray CSO PKS 1718–649

2018 ◽  
Vol 14 (S342) ◽  
pp. 176-179
Author(s):  
Giulia Migliori
Keyword(s):  
Radio Galaxy ◽  
Radio Galaxies ◽  
High Energy ◽  
Radio Sources ◽  
Host Galaxies ◽  
X Ray ◽  
High Energies ◽  
Γ Rays ◽  
Γ Ray ◽  
High Energy Emission

AbstractObservations at high-energies are important to define the first stages of the evolution of extragalactic radio sources and to characterize the interstellar medium of their host galaxies. In some of the X-ray-observed Compact Symmetric Objects (CSOs, among the youngest and most compact radio galaxies), we measured values of the total hydrogen column densities large enough to slow or prevent the radio source growth. The γ-ray window has the potential to constrain the non-thermal contribution of jets and lobes to the total high-energy emission. However, so far, young radio sources remain elusive in γ-rays, with only a handful of detections (or candidates) reported by Fermi. I present our γ-ray study of the CSO PKS 1718–649, and draw comparison with the restarted, γ-ray detected, radio galaxy 3C 84.

MULTIWAVELENGTH PROPERTIES OF γ-RAY LOUD BINARY SYSTEMS

2008 ◽  
Vol 17 (10) ◽  
pp. 1917-1924
Author(s):  
M. CHERNYAKOVA ◽  
A. NERONOV
Keyword(s):  
Binary Systems ◽  
Gamma Ray ◽  
High Energy ◽  
X Ray ◽  
Γ Ray ◽  
X Ray Binaries

Gamma-ray-loud binary systems are a newly identified class of X-ray binaries detected up to TeV energies. Three such systems — PSR B1259–63, LS 5039 and LSI +61 303 — have been firmly detected as persistent or regularly variable TeV γ-ray emitters. The origin of the high-energy activity of these sources is not clear. In this paper we review the multiwavelength properties of these systems and discuss their similarities and peculiarities.

The spectrum of γ rays in the energy range 1011 to 1013 eV at an atmospheric depth of 200 g/cm2, and pion generation in high-energy nucleon interactions

1968 ◽  
Vol 46 (10) ◽  
pp. S700-S705 ◽  
Author(s):  
A. V. Apanasenko ◽  
L. T. Baradzei ◽  
E. A. Kanevskaya ◽  
V. V. Rykov ◽  
Yu. A. Smorodin ◽  
...  
Keyword(s):  
Energy Range ◽  
High Energy ◽  
Nucleon Interaction ◽  
Nuclear Emulsions ◽  
X Ray ◽  
Black Spots ◽  
Γ Rays ◽  
Γ Ray ◽  
Using Data ◽  
Electron Photon

The problem of the existence of a change of slope in the γ-ray spectrum in the atmosphere is of considerable interest in connection with conclusions about the change in the character of the nucleon interaction. Up to now this problem has not been solved experimentally. In this report the γ-ray spectrum in the 1011–1013 eV energy range has been obtained using data from X-ray films and nuclear emulsions exposed on board an airplane at a pressure of 200 g/cm2. The total exposure was 425 hours∙m2. The energies of the electron–photon cascades initiated by γ rays were determined in the X-ray films by measuring the photometric densities of the black spots, and in nuclear emulsions by counting the electron tracks near the cascade axis. The integral spectrum has a power-law form with an exponent of 1.7–1.9. A change in slope in the spectrum was not found. Thus, a mechanism generating pions with energies proportional to the initial nucleon energies exists up to nucleon energies of ~1014 eV. The analysis of the accompaniment of γ rays by "families" shows that in one-third of the cases the energy of the most energetic π0 meson is at least five times that of the next π0 meson. In the remaining two-thirds of the cases the π0 mesons have comparable energies.

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