Y. Hayashi

Observations of TeV Gamma-Ray Flares from Markarian 501with the Telescope Array Prototype

We will report the observations of TeV gamma ray flares from Markarian 501 using Telescope Array Prototype. The observation were carried out continuously from the end of March to the end of July in 1997. The energy spectrum, and the time variation of the gamma ray intensities are shown. The intensity has been changed by the order of magnitude in this period and the possible quasi periodic oscillation of 12.7days were discovered.We report the observations of TeV gamma-ray flares from Markarian 501 using the Telescope Array Prototype. The observations were carried out continuously from the end of March to the end of July of 1997. The energy spectrum and the time variation of the gamma-ray intensities are shown. The intensity has been changed by an order of magnitude in this period, and the possible quasi-periodic oscillation of 12.7 days were discovered.

Energy spectrum of TeV gamma rays from Mrk 501 obtained by stereoscopic analysis

Abstract We have observed flares of TeV-gamma rays from Mrk501 in 1997 using three telescopes of the Utah Seven Telescope Array at Dugway, Utah. Determination of the energy spectrum from such Active Galactic Nuclei (AGN) is very important, because the gamma-ray spectrum is expected to steepen around 10 TeV from objects like Mrk501 by the interaction of the infrared photons. We have developed the method to estimate energies of the gamma rays by stereoscopic analysis using multiple telescopes. The differential index of the energy spectrum obtained is well expressed by −2.5 between 700 GeV and 3 TeV. This spectrum seems to become steeper above several TeV.

Transient weakening of geomagnetic shield probed by GRAPES-3 experiment

The large area (560 m

Diffusion of cosmic rays in heliosphere, observations from GRAPES-3

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Atmospheric temperature dependence of muon intensity measured by the GRAPES-3 experiment

) GRAPES-3 tracking muon telescope in Ooty, India recorded a 2 hour (h) muon burst on 22 June 2015 starting at 19:00 UT in the midst of a continuing Forbush decrease. The burst occurred following the arrival of a coronal mass ejection containing a 40 nT south-ward interplanetary magnetic field (IMF) that had triggered a G4 class geomagnetic storm. During the 2 hour, the muon telescope recorded an excess of

Extending the range of particle densities observed by GRAPES-3

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Long-term correction of GRAPES-3 muon telescope efficiency

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CORSIKA modification for electric field simulations on pions, kaons and muons

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Measuring the hourly gain of the scintillator detectors from EAS data

muons with a significance of 54

Precision measurement of arrival times in an EAS by GRAPES-3 experiment

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