Gamma-ray flux depressions of the Crab nebula in the high-energy range
arXiv:2004.03964 · doi:10.1093/mnras/staa1921
Abstract
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 analysis of 10.5 years of Fermi-LAT observations (Aug 2008 -- Feb 2019) and investigated variability of the Crab nebula in the 100-300 MeV range. Besides the flares, we found several month long depressions of the gamma-ray flux and identified several cases of sharp flux drops, where during one week the flux decreased by an order of magnitude with respect to its average value. No statistically significant variations of the nebula flux in the 10 GeV range were found in the data. We discuss possible implications of the observed gamma-ray flux depressions on the model of synchrotron emission of the Crab nebula.
arXiv comment7 pages, 8 figures, matches the published version
References in corpus (20)
- Fermi Large Area Telescope Fourth Source Catalog
- Fermi Large Area Telescope First Source Catalog
- Gamma-ray flares from the Crab Nebula
- Discovery of Powerful Gamma-Ray Flares from the Crab Nebula
- Simulations of particle acceleration beyond the classical synchrotron burnoff limit in magnetic reconnection: An explanation of the Crab flares
- The extent of power-law energy spectra in collisionless relativistic magnetic reconnection in pair plasmas
- The surprising Crab pulsar and its nebula: A review
- Relativistic Shocks: Particle Acceleration and Magnetization
- Three-Dimensional Magnetohydrodynamic Simulations of the Crab Nebula
- Gamma-ray Activity in the Crab Nebula: The Exceptional Flare of April 2011
- When A Standard Candle Flickers
- Pulsar Wind Nebulae as Cosmic Pevatrons: A Current Sheet's Tale
- On the origin of variable gamma-ray emission from the Crab Nebula
- Variable gamma-ray emission from the Crab Nebula: short flares and long "waves"
- Twinkling pulsar wind nebulae in the synchrotron cut-off regime and the gamma-ray flares in the Crab Nebula
- PIC Simulation Methods for Cosmic Radiation and Plasma Instabilities
- Crab flares due to turbulent dissipation of the pulsar striped wind
- Modelling Jets, Tori and Flares in Pulsar Wind Nebulae
- A corrugated termination shock in pulsar wind nebulae?
- A systematic study of -ray flares from the Crab Nebula with Fermi-LAT: I. flare detection