Results 21 to 30 of about 196,917 (331)

EXTRAGALACTIC GAMMA-RAYS: GAMMA RAY BURSTS AND BLAZARS [PDF]

open access: yesInternational Journal of Modern Physics A, 2005
The extragalactic gamma-ray sky is dominated by two classes of sources: Gamma-Ray Bursts (GRBs) and radio loud active galactic nuclei whose jets are pointing at us (blazars). We believe that the radiation we receive from them originates from the transformation of bulk relativistic energy into random energy.
openaire   +3 more sources

Simultaneous multi-nuclide imaging via double-photon coincidence method with parallel hole collimators

open access: yesScientific Reports, 2021
Multi-tracer imaging can provide useful information in the definitive diagnosis and research of medical, biological, and pharmaceutical sciences. Single-photon emission computed tomography (SPECT) is one of the nuclear medicine imaging modalities widely ...
Mizuki Uenomachi   +3 more
doaj   +1 more source

Multi-frequency, Multi-Epoch Study of Mrk 501: Hints for a two-component nature of the emission [PDF]

open access: yes, 2015
Since the detection of very high energy (VHE) $\gamma$-rays from Mrk 501, its broad band emission of radiation was mostly and quite effectively modeled using one zone emission scenario.
Acharya, B. S.   +10 more
core   +2 more sources

Absorption of High Energy Gamma Rays by Interactions with Extragalactic Starlight Photons at High Redshifts [PDF]

open access: yes, 1997
We extend earlier calculations of the attenuation suffered by gamma rays during their propagation from extragalactic sources, obtaining new extinction curves for gamma rays down to 10 GeV in energy, from sources up to a redshift of z=3.Comment: 5 pages ...
Salamon, M. H., Stecker, F. W.
core   +2 more sources

Gamma-ray binaries [PDF]

open access: yesAstrophysics and Space Science, 2007
Recent observations have shown that some compact stellar binaries radiate the highest energy light in the universe. The challenge has been to determine the nature of the compact object and whether the very high energy gamma-rays are ultimately powered by pulsar winds or relativistic jets.
openaire   +3 more sources

Analyzing {\gamma}-rays of the Galactic Center with Deep Learning [PDF]

open access: yes, 2018
We present a new method to interpret the $\gamma$-ray data of our inner Galaxy as measured by the Fermi Large Area Telescope (Fermi LAT). We train and test convolutional neural networks with simulated Fermi-LAT images based on models tuned to real data ...
Caron, Sascha   +3 more
core   +3 more sources

GAMMA-RAY OBSERVATIONS OF GAMMA-RAY BINARIES [PDF]

open access: yesInternational Journal of Modern Physics: Conference Series, 2014
Gamma-ray binaries are binary systems that emit most of their radiative output above 1 MeV. Following the detection of five such systems in the past decade, they have been clearly established as a population of galactic GeV and TeV sources. In this review I discuss their recent gamma-ray observational results from Cherenkov telescopes and the Fermi ...
openaire   +1 more source

New applications and developments in the neutron shielding

open access: yesEPJ Web of Conferences, 2017
Shielding neutrons involve three steps that are slowing neutrons, absorption of neutrons, and impregnation of gamma rays. Neutrons slow down with thermal energy by hydrogen, water, paraffin, plastic. Hydrogenated materials are also very effective for the
Uğur Fatma Aysun
doaj   +1 more source

GAMMA-RAY BURSTS [PDF]

open access: yesParticles, Strings and Cosmology (PASCOS 99), 2000
Ultra-high-energy, >10^19 eV, cosmic-ray and high energy, ~10^14 eV, neutrino production in GRBs is discussed in the light of recent GRB and cosmic-ray observations. Emphasis is put on model predictions that can be tested with operating and planned cosmic-ray and neutrino detectors, and on the prospects of testing for neutrino properties.
openaire   +4 more sources

Gamma-Ray Bursts

open access: yes, 2022
Gamma-ray bursts (GRB) are short and intense bursts of $\sim$100 keV$-$1MeV photons, usually followed by long-lasting decaying afterglow emission in a wide range of electromagnetic wavelengths from radio to X-ray and, sometimes, even to GeV gamma-rays.
Yu, Yun-Wei   +3 more
openaire   +2 more sources

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