Related papers: First Results on the Performance of the HEGRA IACT…
The ``Gamma Ray Astronomy at ALmeria'' (GRAAL) experiment uses 63 heliostat-mirrors with a total mirror area of ~ 2500 m2 from the CESA-1 field at the ``Plataforma Solar de Almeria'' (PSA) to collect Cherenkov light from air showers. The…
During the last decade ground-based very high-energy gamma-ray astronomy achieved a remarkable advancement in the development of the observational technique for the registration and study of gamma-ray emission above 100 GeV. It is widely…
The Crab Nebula is a unique laboratory for studying the acceleration of electrons and positrons through their non-thermal radiation. Observations of very-high-energy $\gamma$ rays from the Crab Nebula have provided important constraints for…
Observations of the Crab Nebula have proven to be the best tool to calibrate and to characterize the performance of a Cherenkov telescope. Scientifically, it is interesting to measure the energy spectrum of the Crab Nebula close to the…
Two Chandra observations have been used to search for thermal X-ray emission from within and around the Crab Nebula. Dead-time was minimized by excluding the brightest part of the Nebula from the field of view. A dust-scattered halo…
We have carried out a near-infrared, narrow-band imaging survey of the Crab Nebula, in the H2 2.12 micron and Br-gamma 2.17 micron lines, using the Spartan Infrared camera on the SOAR Telescope. Over a 2.8' x 5.1' area that encompasses…
The Crab Nebula is a bright emitter of non-thermal radiation across the entire accessible range of wavelengths. The spatial and spectral structures of the synchrotron nebula are well-resolved from radio to hard X-ray emission. The un-pulsed…
Blazars with redshifts z<0.1 are likely candidates for detection at energies in the range 300 GeV - 50 TeV with Cerenkov telescopes and scintillator arrays. We present gamma-ray flux predictions for a sample of 15 nearby flat-spectrum radio…
Aims: We aim to measure the Crab Nebula gamma-ray spectral energy distribution in the ~100 TeV energy domain and test the validity of existing leptonic emission models at these high energies. Methods: We use the novel very large zenith…
The Crab Nebula was discovered as the first very-high-energy gamma-ray source by the Whipple Observatory in 1989. Thirty years after its discovery it is still the reference source and the standard candle for Imaging Atmospheric Cherenkov…
The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is a new ground-based atmospheric Cherenkov telescope for gamma-ray astronomy. STACEE uses the large mirror area of a solar heliostat facility to achieve a low energy…
MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located in the Canary island of La Palma. Since autumn 2009 both telescopes have been working together in stereoscopic mode, providing a significant improvement with respect…
The MAGIC telescope has detected for the first time pulsed gamma-rays from the Crab pulsar in the VHE domain. The observations were performed with a newly developed trigger system that allows us to lower the energy threshold of the…
We present results of Crab observations by the INTEGRAL instruments. A simultaneous fit allows us to demonstrate that INTEGRAL provides reliable spectra over its wide energy range.
At present, the ground-based astronomy of very high energy (VHE) (E>100 GeV) gamma-rays experiences the challenging transition phase caused by the substantial upgrading of its observational instrumentation. Recently the HEGRA collaboration…
A detection of TeV $\gamma$-rays from Mkn 501 is reported, based on observations made between March and August 1996 with the first HEGRA Cherenkov telescope (CT1). From the image analysis, 351 excess candidate $\gamma$-ray events are…
The Single-Mirror Small-Size Telescope (SST-1M) stereoscopic system is composed of two Imaging Atmospheric Cherenkov Telescopes (IACTs) designed for optimal performance for gamma-ray astronomy in the multi-TeV energy range. It features a…
The Chandra X-ray Observatory observed the Crab Nebula and Pulsar during orbital calibration. Zeroth-order images with the High-Energy Transmission Grating (HETG) read-out by the Advanced CCD Imaging Spectrometer spectroscopy array (ACIS-S)…
In 2007 a prototype of a new analog Sum-Trigger was installed in the MAGIC I telescope, which lowered the trigger threshold from 55 GeV to 25 GeV and led to the detection of pulsed gamma radiation from the Crab pulsar. To eliminate the need…
Purpose: The Low-Energy X-ray telescope (LE) is a main instrument of the Insight-HXMT mission and consists of 96 Swept Charge Devices (SCD) covering the 1-10 keV energy band. The energy gain and resolution are continuously calibrated by…