Related papers: Gamma Ray Glow Observations at 20-km Altitude
Some gamma-ray burst (GRB) spectra exhibit high energy tails with the highest photon energy detected at 18 GeV. The spectral slope of the high-energy tails is sufficiently flat in nu F_nu to consider the possibility of their detection at…
We analyze the gamma-ray emission from 9 high latitude, translucent molecular clouds taken with the Fermi Large Area Telescope (LAT) between 250 MeV and 10 GeV. Observations of gamma-rays allow us to probe the density and spectrum of cosmic…
The all-sky survey in high-energy gamma rays (E$>$30 MeV) carried out by the Energetic Gamma Ray Experiment Telescope (EGRET) aboard the Compton Gamma-Ray Observatory provides a unique opportunity to examine in detail the diffuse gamma-ray…
Blazars outburst provide an opportunity to study their spectral behaviour, correlated variations, and structure of the jet. Such an unprecedented flaring activity in FSRQ CTA102, during 2016 - 2017, is used for a detailed study to…
During a winter thunderstorm on 2017 November 24, a strong burst of gamma rays with energies up to $\sim$10~MeV was detected coincident with a lightning discharge, by scintillation detectors installed at Kashiwazaki-Kariwa Nuclear Power…
The NASA Global-scale Observations of the Limb and Disk (GOLD) ultraviolet imaging spectrograph performs observations of upper-atmosphere airglow from the sunlit disk and limb of the Earth, in order to infer quantities such as the…
The Earth's high energy gamma-ray emission is caused by cosmic ray interactions with the atmosphere. The EGRET detector on-board the CGRO satellite is only the second experiment (after SAS-2) to provide a suitable dataset for the…
Lightning was detected by Voyager 2 at Uranus and Neptune, and weaker electrical processes also occur throughout planetary atmospheres from galactic cosmic ray (GCR) ionisation. Lightning is an indicator of convection, whereas electrical…
Many classes of gamma-ray sources, such as gamma-ray bursts, blazars, Seyfert galaxies, and galactic black hole sources are surrounded by large amounts of gas and dust. X-rays and gamma-rays that traverse this material will be attenuated by…
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…
The Large High Altitude Air Shower Observatory (LHAASO) has three sub-arrays, KM2A, WCDA and WFCTA. The flux variations of cosmic ray air showers were studied by analyzing the KM2A data during the thunderstorm on 10 June 2021. The number of…
The recently completed High Altitude Water Cherenkov (HAWC) gamma-ray observatory has been taking data with a partial array for more than one year and is now operating with >95% duty cycle in its full configuration. With an instantaneous…
Interstellar clouds can act as target material for hadronic cosmic rays; gamma-rays produced through inelastic proton-proton collisions and spatially associated with the clouds provide a key indicator of efficient particle acceleration.…
The detection of delayed X-ray, optical and radio emission, "afterglow", associated with $\gamma$-ray bursts (GRBs) is consistent with fireball models, where the emission are produced by relativistic expanding blast wave, driven by…
Recent follow-up observations of the December 27 giant flare of SGR 1806-20 have detected a multiple-frequency radio afterglow from 240 MHz to 8.46 GHz, extending in time from a week to about a month after the flare. The angular size of the…
The origin of the diffuse extragalactic, high-energy gamma-ray background (EGRB) filling the Universe remains unknown. The spectrum of this extragalactic radiation, as measured by the EGRET on-board CGRO, is well-fit by a power law across…
Gamma-ray burst astronomy has undergone a revolution in the last three years, spurred by the discovery of fading long-wavelength counterparts. We now know that at least the long duration GRBs lie at cosmological distances with estimated…
Gamma-ray bursts (GRBs) are bright flashes of gamma-rays coming from the cosmos. They occur roughly once per day, last typically 10s of seconds and are the most luminous events in the universe. More than three decades after their discovery,…
The EGRET instrument aboard the Compton Gamma Ray Observatory (CGRO) has completed the first all-sky survey in high-energy gamma rays and has repeatedly viewed selected portions of the sky. Analysis of the region with galactic latitude…
Gamma-ray bursts (GRBs) are cosmic events occurring at large distances beyond our galaxy. They provide a unique opportunity to study electromagnetic patterns not seen elsewhere. When the collimated GRB outflow interacts with the outer…