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Aims. The BL Lac object RGB J0152+017 (z = 0.080) was predicted to be a very high-energy (VHE; > 100 GeV) γ-ray source, due to its high X-ray and radio fluxes. Our aim is to understand the radiative processes by investigating the observed emission and its production mechanism using the High Energy Stereoscopic System (H.E.S.S.) experiment. Methods. We(More)
EEG recordings from 56 alcoholics (20 women) and 9 nonalcoholic controls (15 women) were compared using power spectral density and coherence techniques. Alcoholics had more power in the delta frequency bands (1-4 Hz) and less power in alpha (9-13 Hz) from all regions of the skull. Interhemispheric coherence scores from homologous brain sites were greater(More)
In the past few decades, several models have predicted an energy dependence of the speed of light in the context of quantum gravity. For cosmological sources such as active galaxies, this minuscule effect can add up to measurable photon-energy dependent time lags. In this Letter a search for such time lags during the High Energy Stereoscopic System(More)
The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles to energies exceeding 10(12) electron volts and are bright sources of very-high-energy (VHE) gamma-ray emission, it is not yet known where the VHE emission originates. Here we(More)
The giant radio galaxy M 87 with its proximity (16 Mpc), famous jet, and very massive black hole ((3 − 6) × 10 9 M) provides a unique opportunity to investigate the origin of very high energy (VHE; E>100 GeV) γ-ray emission generated in relativistic outflows and the surroundings of super-massive black holes. M 87 has been established as a VHE γ-ray emitter(More)
Starburst galaxies exhibit in their central regions a highly increased rate of supernovae, the remnants of which are thought to accelerate energetic cosmic rays up to energies of approximately 10(15) electron volts. We report the detection of gamma rays--tracers of such cosmic rays--from the starburst galaxy NGC 253 using the High Energy Stereoscopic System(More)
Aims. Results from γ-ray observations by the H.E.S.S. telescope array in the direction of the young stellar cluster Westerlund 2 are presented. Methods. Stereoscopic imaging of Cherenkov light emission of γ-ray induced showers in the atmosphere is used to study the celestial region around the massive Wolf-Rayet (WR) binary WR 20a. Spectral and positional(More)
Aims. We present the results of a search for pulsed very-high-energy (VHE) γ-ray emission from young pulsars using data taken with the H.E.S.S. imaging atmospheric Cherenkov telescope system. Methods. Data on eleven pulsars, selected according to their spin-down luminosity relative to distance, are searched for γ-ray signals with periodicity at the(More)