A young and energetic pulsar powers the well-known Crab Nebula. Here, we describe two separate gamma-ray (photon energy greater than 100 mega-electron volts) flares from this source detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The first flare occurred in February 2009 and lasted approximately 16 days. The second flare was detected in September 2010 and lasted approximately 4 days. During these outbursts, the gamma-ray flux from the nebula increased by factors of four and six, respectively. The brevity of the flares implies that the gamma rays were emitted via synchrotron radiation from peta-electron-volt (10(15) electron volts) electrons in a region smaller than 1.4 x 10(-2) parsecs. These are the highest-energy particles that can be associated with a discrete astronomical source, and they pose challenges to particle acceleration theory.

Gamma-Ray Flares from the Crab Nebula / Abdo, A.a., Ackermann, M., Ajello, M., Allafort, A., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R.d., Bloom, E.d., Bonamente, E., Borgland, A.w., Bouvier, A., Brandt, T.j., Bregeon, J., Brez, A., Brigida, M., et al.. - In: SCIENCE. - ISSN 0036-8075. - 331:6018(2011), pp. 739-742. [10.1126/science.1199705]

Gamma-Ray Flares from the Crab Nebula

FAVUZZI, Cecilia;GIGLIETTO, Nicola;
2011

Abstract

A young and energetic pulsar powers the well-known Crab Nebula. Here, we describe two separate gamma-ray (photon energy greater than 100 mega-electron volts) flares from this source detected by the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. The first flare occurred in February 2009 and lasted approximately 16 days. The second flare was detected in September 2010 and lasted approximately 4 days. During these outbursts, the gamma-ray flux from the nebula increased by factors of four and six, respectively. The brevity of the flares implies that the gamma rays were emitted via synchrotron radiation from peta-electron-volt (10(15) electron volts) electrons in a region smaller than 1.4 x 10(-2) parsecs. These are the highest-energy particles that can be associated with a discrete astronomical source, and they pose challenges to particle acceleration theory.
2011
Gamma-Ray Flares from the Crab Nebula / Abdo, A.a., Ackermann, M., Ajello, M., Allafort, A., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R.d., Bloom, E.d., Bonamente, E., Borgland, A.w., Bouvier, A., Brandt, T.j., Bregeon, J., Brez, A., Brigida, M., et al.. - In: SCIENCE. - ISSN 0036-8075. - 331:6018(2011), pp. 739-742. [10.1126/science.1199705]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11589/51909
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