Fermi gamma-ray space telescope observations of gamma-ray outbursts from 3C 454.3 in 2009 december and 2010 april

M. Ackermann, M. Ajello, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. Bonamente, A. W. Borgland, J. Bregeon, M. Brigida, P. Bruel, R. Buehler, T. H. Burnett, S. Buson, G. A. Caliandro, R. A. CameronP. A. Caraveo, S. Carrigan, J. M. Casandjian, E. Cavazzuti, C. Cecchi, Ö Çelik, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, S. Corbel, S. Cutini, F. D'Ammando, C. D. Dermer, A. De Angelis, F. De Palma, S. W. Digel, E. Do Couto E Silva, P. S. Drell, R. Dubois, D. Dumora, L. Escande, C. Favuzzi, S. J. Fegan, E. C. Ferrara, L. Fuhrmann, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, J. E. Grove, S. Guiriec, D. Hadasch, M. Hayashida, E. Hays, G. Jóhannesson, A. S. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, J. Kataoka, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, L. Latronico, S. H. Lee, M. Llena Garde, F. Longo, F. Loparco, B. Lott, P. Lubrano, G. M. Madejski, A. Makeev, N. Marchili, M. N. Mazziotta, J. E. McEnery, J. Mehault, P. F. Michelson, T. Mizuno, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, T. Nakamori, K. Nalewajko

Research output: Contribution to journalArticle

115 Citations (Scopus)

Abstract

The flat spectrum radio quasar 3C 454.3 underwent an extraordinary outburst in 2009 December when it became the brightest γ -ray source in the sky for over 1 week. Its daily flux measured with the Fermi-Large Area Telescope at photon energiesE > 100 MeV reached F100 = 22 ± 1 × 10 -6 photon cm-2 s-1, representing the highest daily flux of any blazar ever recorded in high-energy γ -rays. It again became the brightest source in the sky in 2010 April, triggering a pointed-mode observation by Fermi. The correlated γ -ray temporal and spectral properties during these exceptional events are presented and discussed. The main results show flux variability over time scales less than 3 hr and very mild spectral variability with an indication of gradual hardening preceding major flares. The light curves during periods of enhanced activity in 2008 July-August and 2010 December show strong resemblance, with a flux plateau of a few days preceding the major flare. No consistent loop pattern emerged in the γ -ray spectral index versus the flux plane as would be expected in acceleration and cooling scenarios. The maximum energy of a photon from 3C 454.3 is ≈20 GeV and a minimum Doppler factor of ≈13 is derived. The γ -ray spectrum of 3C 454.3 shows a significant spectral break between ≈2 and 3 GeV that is very weakly dependent on the flux state, even when the flux changes by an order of magnitude.

Original languageEnglish
Pages (from-to)1383-1396
Number of pages14
JournalAstrophysical Journal
Volume721
Issue number2
DOIs
Publication statusPublished - 2010 Oct 1

Keywords

  • Galaxies: active
  • Gamma rays: galaxies
  • Quasars: individual (3C 454.3)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Ackermann, M., Ajello, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R. D., Bonamente, E., Borgland, A. W., Bregeon, J., Brigida, M., Bruel, P., Buehler, R., Burnett, T. H., Buson, S., Caliandro, G. A., ... Nalewajko, K. (2010). Fermi gamma-ray space telescope observations of gamma-ray outbursts from 3C 454.3 in 2009 december and 2010 april. Astrophysical Journal, 721(2), 1383-1396. https://doi.org/10.1088/0004-637X/721/2/1383