FERMI-LARGE AREA TELESCOPE OBSERVATIONS OF THE EXCEPTIONAL GAMMA-RAY OUTBURSTS OF 3C 273 IN 2009 SEPTEMBER

Journal Article · Sat May 01 00:00:00 EDT 2010 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/714/1/L73; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21305002

Abdo, A A ^[1]; Ackermann, M; Ajello, M; Bechtol, K; Berenji, B; Blandford, R D; Bloom, E D; Borgland, A W; Bouvier, A ^[2]; Baldini, L; Bellazzini, R; Bregeon, J; Brez, A ^[3]; Ballet, J ^[4]; Barbiellini, G ^[5]; Bastieri, D ^[6]; Bonamente, E ^[7]; Brigida, M ^[8]; Bruel, P ^[9]

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1. Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States)
2. W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)
3. Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy)
4. Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d'Astrophysique, CEA Saclay, 91191 Gif sur Yvette (France)
5. Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy)
6. Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy)
7. Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy)
8. Dipartimento di Fisica 'M. Merlin' dell'Universita e del Politecnico di Bari, I-70126 Bari (Italy)
9. Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Palaiseau (France)

We present the light curves and spectral data of two exceptionally luminous gamma-ray outbursts observed by the Large Area Telescope experiment on board the Fermi Gamma-ray Space Telescope from 3C 273 in 2009 September. During these flares, having a duration of a few days, the source reached its highest {gamma}-ray flux ever measured. This allowed us to study, in some details, their spectral and temporal structures. The rise and the decay are asymmetric on timescales of 6 hr, and the spectral index was significantly harder during the flares than during the preceding 11 months. We also found that short, very intense flares put out the same time-integrated energy as long, less intense flares like that observed in 2009 August.

• OSTI ID: 21305002
• Journal Information: Astrophysical Journal Letters, Vol. 714, Issue 1; Other Information: DOI: 10.1088/2041-8205/714/1/L73; Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ASYMMETRY
GALAXIES
GAMMA RADIATION
QUASARS
TELESCOPES