Related papers: Pulsar Radiation and Quantum Gravity
The Crab pulsar and the surrounding nebula powered by the pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind is a bright source of gamma-rays carrying crucial information about this…
Spontaneous breaking of Lorentz symmetry at energies on the order of the Planck energy or lower is predicted by many quantum gravity theories, implying non-trivial dispersion relations for the photon in vacuum. Consequently, gamma-rays of…
The last six years have witnessed major revisions of our knowledge about the Crab Pulsar. The consensus scenario for the origin of the high-energy pulsed emission has been challenged with the discovery of a very-high-energy power law tail…
In the present paper a self-consistent theory, interpreting the VERITAS observations of the very high energy pulsed emission from the Crab pulsar is considered. The photon spectrum between 10MeV and 400GeV can be described by two power-law…
The Crab pulsar has been widely studied across the electromagnetic spectrum from radio to gamma-ray energies. The exact nature of the emission processes taking place in the pulsar is a matter of broad debate. Above a few GeV the energy…
We report the detection of pulsed gamma rays from the Crab pulsar at energies above 100 Gigaelectronvolts (GeV) with the VERITAS array of atmospheric Cherenkov telescopes. The detection cannot be explained on the basis of current pulsar…
We have used data from the TeV gamma-ray flare associated with the active galaxy Markarian 421 observed on 15 May 1996 to place bounds on the possible energy-dependence of the speed of light in the context of an effective quantum…
We present the detection of pulsed gamma-ray emission from the Crab Pulsar above 100 GeV with the VERITAS array of atmospheric Cherenkov telescopes. Gamma-ray emission at theses energies is not expected in present pulsar models. We find…
The Fermi space telescope has detected over 100 pulsars. These discoveries have ushered in a new era of pulsar astrophysics at gamma-ray energies. Gamma-ray pulsars, regardless of whether they are young, old, radio-quiet etc, all exhibit a…
We present direct upper limits on gravitational wave emission from the Crab pulsar using data from the first nine months of the fifth science run of the Laser Interferometer Gravitational-wave Observatory (LIGO). These limits are based on…
We show that the mysterious, rapidly variable emission at ~400 MeV observed from the Crab Nebula by the AGILE and Fermi experiments could be the result of a sudden drop in the mass-loading of the pulsar wind. The current required to…
We present the results of a search for pulsed TeV emission from the Crab pulsar using the Whipple Observatory's 10m gamma-ray telescope. The direction of the Crab pulsar was observed for a total of 73.4 hours between 1994 November and 1997…
We discuss the recent detection of pulsed gamma-ray emission from the Crab Pulsar above 100 GeV with the VERITAS array of atmospheric Cherenkov telescopes. Gamma-ray emission at theses energies is not expected in present pulsar models. We…
The Crab nebula is one of the most studied cosmic particle accelerators, shining brightly across the entire electromagnetic spectrum up to very high-energy gamma rays. It is known from radio to gamma-ray observations that the nebula is…
We present the detection of pulsed gamma-ray emission from the Crab pulsar above 100 GeV with the VERITAS array of atmospheric Cherenkov telescopes. Gamma-ray emission at theses energies was not expected in pulsar models. The detection of…
One fundamental question about pulsars concerns the mechanism of their pulsed electromagnetic emission. Measuring the high-end region of a pulsar's spectrum would shed light on this question. By developing a new electronic trigger, we…
Some models for quantum gravity (QG) violate Lorentz invariance and predict an energy dependence of the speed of light, leading to a dispersion of high-energy gamma-ray signals that travel over cosmological distances. Limits on the…
The origin of very energetic charged particles and the production of very high-energy (VHE) gamma-ray emission remains still a challenging issue in modern pulsar physics. By applying a toy model, we explore the acceleration of co-rotating…
We report about very high energy (VHE) gamma-ray observations of the Crab Nebula with the MAGIC telescope. The gamma-ray flux from the nebula was measured between 60 GeV and 9 TeV. The energy spectrum can be described with a curved power…
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…