Discovery of Powerful Gamma-Ray Flares from the Crab Nebula

  title={Discovery of Powerful Gamma-Ray Flares from the Crab Nebula},
  author={Marco Tavani and Andrea Bulgarelli and Valeria Vittorini and Alberto Pellizzoni and Edoardo Striani and Patrizia A. Caraveo and Martin C. Weisskopf and Allyn F. Tennant and G. Pucella and Alessio Trois and Enrico Costa and Yuri Evangelista and Carlotta Pittori and Francesco Verrecchia and Ettore Del Monte and Riccardo Campana and Maura Pilia and Andrea De Luca and Immacolata Donnarumma and Dieter Horns and Carlo Ferrigno and Craig O. Heinke and Massimo Trifoglio and Fulvio Gianotti and Stefano Vercellone and Andrea Argan and Guido Barbiellini and Paolo Walter Cattaneo and A. W. Chen and T. Contessi and Filippo D’Ammando and G DePris and Guido Di Cocco and Giuseppe Di Persio and Marco Feroci and Attilio Ferrari and M. Galli and Alessandro Giuliani and Manuela Giusti and Claudio Labanti and Igor Y. Lapshov and Francesco Lazzarotto and Paolo Lipari and Francesco Longo and Fabio Fuschino and Martino Marisaldi and Sandro Mereghetti and Ennio Morelli and E. Moretti and A. Morselli and Luigi Pacciani and Francesco Perotti and Giovanni Piano and Piergiorgio Picozza and M. Prest and Massimo Rapisarda and Andrea Rappoldi and Alda Rubini and Silvio P. Sabatini and Paolo Soffitta and Erik Vallazza and A. Zambra and D. P. Zanello and Fabrizio Lucarelli and Patrizia Santolamazza and Paolo Giommi and Luca Salotti and Giovanni Fabrizio Bignami},
  pages={736 - 739}
Gamma-ray observations of the Crab Nebula by two different space telescopes challenge particle acceleration theory. The well-known Crab Nebula is at the center of the SN1054 supernova remnant. It consists of a rotationally powered pulsar interacting with a surrounding nebula through a relativistic particle wind. The emissions originating from the pulsar and nebula have been considered to be essentially stable. Here, we report the detection of strong gamma-ray (100 mega–electron volts to 10 giga… 
Gamma-Ray Flares from the Crab Nebula
Two separate gamma-ray flares from a young and energetic pulsar powers the well-known Crab Nebula are described and it is suggested that the gamma rays were emitted via synchrotron radiation from peta–electron-volt electrons in a region smaller than 1.4 × 10−2 parsecs.
Gamma-ray flux depressions of the Crab Nebula in the high-energy range
The giant gamma-ray flares of the Crab nebula discovered by AGILE and Fermi observatories came as a surprise and have challenged the existing models of pulsar wind nebulae. We have carried out an
On the origin of variable gamma-ray emission from the Crab nebula
The oblique geometry of the pulsar wind termination shock ensures that the Doppler beaming has a strong impact on the shock emission. We illustrate this using the recent relativistic
Peta–electron volt gamma-ray emission from the Crab Nebula
Observations of the Crab Nebula at peta–electron volt energies constrains the gamma-ray emission mechanism and reports the detection of gamma rays from this source with a spectrum showing gradual steepening over three energy decades.
The Crab Nebula super-flare in April 2011: extremely fast particle acceleration and gamma-ray emission
We report on the extremely intense and fast gamma-ray are above 100 MeV detected by AGILE from the Crab Nebula in mid-April 2011. This event is the fourth of a sequence of reported major gamma-ray
Crab nebula gamma-ray flares as relativistic reconnection minijets
The unusually short durations, high luminosities and high photon energies of the Crab nebula gamma-ray flares require the relativistic bulk motion of the emitting plasma. We explain the Crab flares
Detection of Small Flares from the Crab Nebula with Fermi-LAT
Gamma radiation from the Crab pulsar wind nebula (PWN) shows significant variability at $\sim100$ MeV energies, recently revealed with spaceborne gamma-ray telescopes. Here we report the results of a
On the variability of the GeV and multi-TeV gamma-ray emission from the Crab nebula
Recently, the AGILE γ -ray telescope has reported enhanced γ -ray emission above 100 MeV from the direction of the Crab nebula during a period of a few days. This intriguing observation has been
Twinkling pulsar wind nebulae in the synchrotron cut-off regime and the γ-ray flares in the Crab Nebula
Synchrotron radiation of ultrarelativistic particles accelerated in a pulsar wind nebula may dominate its spectrum up to γ-ray energies. Because of the short cooling time of the γ-ray-emitting


Gamma-Ray Flares from the Crab Nebula
Two separate gamma-ray flares from a young and energetic pulsar powers the well-known Crab Nebula are described and it is suggested that the gamma rays were emitted via synchrotron radiation from peta–electron-volt electrons in a region smaller than 1.4 × 10−2 parsecs.
Fermi Large Area Telescope Observations of the Crab Pulsar and Nebula
We report on γ -ray observations of the Crab Pulsar and Nebula using 8 months of survey data with the Fermi Large Area Telescope (LAT). The high quality light curve obtained using the ephemeris
Discovery of Spatial and Spectral Structure in the X-Ray Emission from the Crab Nebula.
Zeroth-order images with the High-Energy Transmission Grating (HETG) readout by the Advanced CCD Imaging Spectrometer spectroscopy array (ACIS-S) show a striking richness of X-ray structure at a resolution comparable to that of the best ground-based visible-light observations.
The Crab Nebula: An Astrophysical Chimera
The Crab Nebula, henceforth the Crab, the remnant of the historical super- nova of 1054 AD, has long been of intense interest. The pulsar at the center of the Crab has a spin-down luminosity ∼10 5
Astro-rivelatore Gamma ad Immagini LEggero (AGILE) is a small gamma-ray astronomy satellite mission of the Italian Space Agency dedicated to high-energy astrophysics launched in 2007 April. Its ∼ 1
Phase-resolved Studies of the High-Energy Gamma-Ray Emission from the Crab, Geminga, and Vela Pulsars
Using the first 3.5 years of observations from the Energetic Gamma Ray Telescope (EGRET) on board the Compton Gamma Ray Observatory, phase-resolved analyses are performed on the emission from the
The expected high-energy to ultra-high-energy gamma-ray spectrum of the Crab Nebula
The inverse Compton scattering model for the unpulsed TeV emission from the Crab Nebula is reexamined using the magnetic field distribution derived from MHD flow models of the nebula. It is shown
Hubble Space Telescope and Chandra Monitoring of the Crab Synchrotron Nebula
We report the results of coordinated Hubble Space Telescope and Chandra observations of the Crab synchrotron nebula. Similar dynamical structures, including equatorial wisps moving outward at ~0.5c,
WFPC2 Studies of the Crab Nebula. I. HST and ROSAT Imaging of the Synchrotron Nebula
We present images of the Crab synchrotron nebula obtained with the Wide Field and Planetary Camera 2 (WFPC2) on board the Hubble Space Telescope. These data are compared with ROSAT HRI images, and
Structure of relativistic shocks in pulsar winds: A model of the wisps in the Crab Nebula
We propose a model of a optical 'wisps' of the Crab Nebula, features observed in the nebular synchrotron surface brightness near the central pulsar, as manifestations of the internal structure of the