Related papers: Termination of Electron Acceleration in Thunderclo…
The electromagnetic radiation that followed the neutron star merger event GW170817 revealed that gamma-ray burst afterglows from jets misaligned with our line of sight exhibit a light curve with slowly rising flux. The slope of the rising…
We present GMRT observations of the Galactic microquasar GRS 1915+105 at 1.28 GHz for 8 days from 2001 June 18 to July 1. We have seen several isolated radio flares of varying magnitudes (20 - 50 mJy) and durations (6 - 35 min) and we model…
Observing early optical emission from gamma-ray bursts (GRBs) contemporaneous with the MeV prompt emission phase remains rare, requiring rapid-response robotic facilities. The Ond\v{r}ejov D50 telescope detected the optical counterpart of…
The multi-messenger observation of gamma-ray burst (GRB)\,170817A from the nearby binary neutron-star merger GW170817 demonstrated that low-energy $\gamma$-ray emission can be observed at relatively large angles from GRB jet axes. If such…
The GRAPES-3 muon telescope located in Ooty, India records rapid ($\sim$10 min) variations in the muon intensity during major thunderstorms. Out of a total of 184 thunderstorms recorded during the interval April 2011-December 2014, the one…
Radio observations of the afterglow of the gamma-ray burst GRB970508 provide unique new constraints on afterglow models. The quenching of diffractive scintillation at 4 week delay provides the first direct estimate of source size and…
The observations of the exceptionally bright gamma-ray burst (GRB) 130427A by the Large Area Telescope aboard the Fermi Gamma-ray Space Telescope provide constraints on the nature of such unique astrophysical sources. GRB 130427A had the…
The afterglow emission from Gamma-Ray Bursts (GRBs) is usually interpreted as synchrotron radiation from relativistic electrons accelerated at the GRB external shock, that decelerates from ultra-relativistic to non-relativistic speeds as it…
We present Ulysses and NEAR data from the detection of the short or intermediate duration (2 s) gamma-ray burst GRB000301C (2000 March 1.41 UT). The gamma-ray burst (GRB) was localised by the Inter Planetary Network (IPN) and RXTE to an…
We observed the optical afterglow of the bright gamma-ray burst GRB030329 on the nights of 2003 March 29, using the Kiso observatory (the University of Tokyo) 1.05 m Schmidt telescope. Data were taken from March 29 13:21:26 UT to 17:43:16…
The BL Lac object (blazar) Mrk 421 was observed during its outburst in April 2004 with the Whipple 10 m telescope for a total of about 24.5 hours. The measured gamma-ray rate varied substantially over the range from 4 to 10 gamma's/min and…
Emission of two short hard X-ray bursts on 2009 June 5 disclosed the existence of a new soft gamma-ray repeater, now catalogued as SGR 0418+5729. After a few days, X-ray pulsations at a period of 9.1 s were discovered in its persistent…
A young and energetic pulsar powers the well-known Crab Nebula. Here we describe two separate gamma-ray (photon energy >100 MeV) flares from this source detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The…
We numerically simulate the gamma-ray burst (GRB) afterglow emission with a one-zone time-dependent code. The temporal evolutions of the decelerating shocked shell and energy distributions of electrons and photons are consistently…
We report our discovery and early time optical, near-infrared, and radio wavelength follow-up observations of the afterglow of the gamma-ray burst GRB 021211. Our optical observations, beginning 21 min after the burst trigger, demonstrate…
We present single-epoch radio afterglow observations of 24 long-duration gamma-ray burst (GRB) on a timescale of >100 d after the burst. These observations trace the afterglow evolution when the blastwave has decelerated to mildly- or…
Terrestrial gamma ray flashes (TGFs) are very short bursts of gamma radiation associated to thunderstorm activity and are the manifestation of the highest-energy natural particle acceleration phenomena occurring on Earth. Photon energies up…
A near-infrared jet emanating from the galactic superluminal source GRS 1915+105, discovered at $\lambda$ = 2.2 micrometer by Sams et al. (1996) on 18-21 July 1995, was not seen later anymore, neither in the Mirabel et al. (1996) images,…
Gamma-ray observations above 200 MeV are conventionally made by satellite-based detectors. The EGRET detector on the Compton Gamma Ray Observatory (CGRO) has provided good sensitivity for the detection of bursts lasting for more than 200…
A very bright and fast varying gamma-ray flare has been detected from the blazar 3C 279 on June 16, 2015. We have studied the broadband spectral energy distribution of the source during the flaring episode and in the low activity state…