Radon Calibration System

Abdalla, Ayman M.; Ismail, A. M.; Al-Naggar, Tayseer I.

doi:10.5772/intechopen.69900

Cited by 4 publications

(2 citation statements)

References 36 publications

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“…Searches for GeV-TeV γ -ray emission from GRB 170817A have been conducted, but no positive signal has been found (210,211). Some short GRBs are accompanied by extended and plateau emissions.…”

Section: Short γ-Ray Bursts and Neutron Star Mergersmentioning

confidence: 99%

High-Energy Multimessenger Transient Astrophysics

Murase

Bartos

2019

Annu. Rev. Nucl. Part. Sci.

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The recent discoveries of high-energy cosmic neutrinos and gravitational waves from astrophysical objects have led to a new era of multimessenger astrophysics. In particular, electromagnetic follow-up observations triggered by these cosmic signals have proved to be highly successful and have brought about new opportunities in time-domain astronomy. We review high-energy particle production in various classes of astrophysical transient phenomena related to black holes and neutron stars, and discuss how high-energy emission can be used to reveal the underlying physics of neutrino and gravitational-wave sources.

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Section: Short γ-Ray Bursts and Neutron Star Mergersmentioning

confidence: 99%

High-Energy Multimessenger Transient Astrophysics

Murase

Bartos

2019

Annu. Rev. Nucl. Part. Sci.

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“…Observation of the blazars by the large area telescope (LAT) onboard the Fermi satellite in energy range from 30 MeV to more than 500 GeV provides a very strong observational evidence regarding the intrinsic MeV-GeV emission from them [29]. Combined MeV-GeV and TeV observations have provided a new tool to constrain the EBL intensity [30,31,32,33,34,35,36,37]. Recently, the Fermi-LAT observations have been used to indirectly measure the EBL from the absorption features seen in the γ-ray spectra of blazars beyond the redshift z > 1 [38,39].…”

Section: Introductionmentioning

confidence: 99%

Extragalactic background light models and GeV-TeV observation of blazars

Singh

Meintjes

2020

NRIAG Journal of Astronomy and Geophysics

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The extragalactic background light (EBL) in the ultraviolet to far-infrared wavelength range is dominated by the emissions from stars in galaxies and reflects the time-integrated history of the light production and reprocessing in the Universe. Direct measurements of the EBL are affected by the interplanetary dust and galactic emission. Hence, the absolute level of EBL is subject to considerable uncertainties. Observations of very high energy (VHE) blazars located at cosmological distances by the Fermi-Large Area Telescope (LAT) and ground-based gamma-ray telescopes (e.g. H.E.S.S., MAGIC, VERITAS, TACTIC) provide a measurement of the EBL that is independent of the direct observations. The interaction of VHE or TeV photons originated from the distant blazars with the low energy EBL photons via e − e + pair-production can be used as a powerful tool to probe the different EBL models in the wavelength range 0.1-1000µm. In this paper, we use two different methods to determine the opacity of the VHE γ-ray photons caused by the low energy EBL photons and study the consequences of six different EBL models. The first method-Model-Dependent Approach, uses various EBL models for estimating the opacity as a function of the source redshift and energy. The second method-Model-Independent Approach, relies on using the simultaneous observations of blazars in the MeV-GeV energy range from the Fermi-LAT and in TeV band from the ground-based Cherenkov telescopes. We make underline assumption that the extrapolation of the LAT spectrum of blazars to TeV energies is either a good estimate or an upper limit for the intrinsic VHE spectrum of the source. We apply this method on the simultaneous observations of a few blazars PKS 2155-304, RGB J0710+591, 1ES 1218+304 and RBS 0413 at different redshifts to demonstrate a comparative study of six prominent EBL models. Opacities of the VHE γ-ray photons predicted by the Model-Independent Approach are systematically larger than the ones estimated from the Model-Dependent Approach using the six EBL models. Therefore, the γ-ray observations of blazars can be used to set a strict upper limit on the opacity of the Universe to the VHE γ-rays at a given redshift.

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Radon Measurement Techniques

Sukanya

Joseph

2023

Environmental Radon

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Radon Calibration System

Cited by 4 publications

References 36 publications

High-Energy Multimessenger Transient Astrophysics

High-Energy Multimessenger Transient Astrophysics

Extragalactic background light models and GeV-TeV observation of blazars

Radon Measurement Techniques

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