Early fermi gamma-ray space telescope observations of the quasar 3c 454.3

A. A. Abdo, M. Ackermann, M. Ajello, W. B. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, M. Battelino, B. M. Baughman, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, A. Bouvier, J. BregeonA. Brez, M. Brigida, P. Bruel, T. H. Burnett, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, E. Charles, S. Chaty, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, L. R. Cominsky, J. Conrad, L. Costamante, S. Cutini, C. D. Dermer, A. De Angelis, F. De Palma, S. W. Digel, E. Do Couto E Silva, D. Donato, P. S. Drell, R. Dubois, D. Dumora, C. Farnier, C. Favuzzi, W. B. Focke, L. Foschini, M. Frailis, L. Fuhrmann, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, P. Giommi, F. Giordano, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, L. Guillemot, S. Guiriec, Y. Hanabata, A. K. Harding, R. C. Hartman, M. Hayashida, E. Hays, R. E. Hughes, G. Jóhannesson, A. S. Johnson, R. P. Johnson, W. N. Johnson, T. Kamae, H. Katagiri, Jun Kataoka, N. Kawai, M. Kerr, J. Knödlseder, M. L. Kocian, F. Kuehn, M. Kuss, L. Latronico, S. H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, E. Massaro, M. N. Mazziotta, J. E. McEnery, S. McGlynn, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, P. L. Nolan, J. P. Norris, E. Nuss, T. Ohsugi, N. Omodei, E. Orlando, J. F. Ormes, D. Paneque, J. H. Panetta, D. Parent, V. Pelassa, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, T. Reposeur, L. C. Reyes, S. Ritz, L. S. Rochester, A. Y. Rodriguez, F. Rahoui, F. Ryde, H. F W Sadrozinski, R. Sambruna, D. Sanchez, A. Sander, P. M Saz Parkinson, C. Sgrò, M. S. Shaw, D. A. Smith, P. D. Smith, G. Spandre, P. Spinelli, J. L. Starck, M. S. Strickman, D. J. Suson, H. Tajima, H. Takahashi, T. Takahashi, T. Tanaka, J. B. Thayer, J. G. Thayer, D. J. Thompson, L. Tibaldo, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, N. Vilchez, M. Villata, V. Vitale, A. P. Waite, B. L. Winer, K. S. Wood, T. Ylinen, J. A. Zensus, M. Ziegler

    Research output: Contribution to journalArticle

    105 Citations (Scopus)

    Abstract

    This is the first report of Fermi Gamma-Ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope, covering 2008 July 7-October 6, indicate strong, highly variable γ-ray emission with an average flux of 3 × 10-6 photons cm-2 s-1, for energies >100 MeV. The γ-ray flux is variable, with strong, distinct, symmetrically shaped flares for which the flux increases by a factor of several on a timescale of about 3 days. This variability indicates a compact emission region, and the requirement that the source is optically thin to pair production implies relativistic beaming with Doppler factor δ>8, consistent with the values inferred from Very Long Baseline Interferometry observations of superluminal expansion (δ 25). The observed γ-ray spectrum is not consistent with a simple power law, but instead steepens strongly above 2 GeV, and is well described by a broken power law with photon indices of 2.3 and 3.5 below and above the break, respectively. This is the first direct observation of a break in the spectrum of a high-luminosity blazar above 100 MeV, and it is likely direct evidence for an intrinsic break in the energy distribution of the radiating particles. Alternatively, the spectral softening above 2GeV could be due to γ-ray absorption via photon-photon pair production on the soft X-ray photon field of the host active galactic nucleus, but such an interpretation would require the dissipation region to be located very close (≲100 gravitational radii) to the black hole, which would be inconsistent with the X-ray spectrum of the source.

    Original languageEnglish
    Pages (from-to)817-823
    Number of pages7
    JournalAstrophysical Journal
    Volume699
    Issue number1
    DOIs
    Publication statusPublished - 2009

    Fingerprint

    Fermi Gamma-ray Space Telescope
    quasars
    rays
    power law
    photons
    pair production
    very long baseline interferometry
    softening
    outburst
    energy
    dissipation
    timescale
    active galactic nuclei
    flares
    energy distribution
    interferometry
    coverings
    x rays
    luminosity
    telescopes

    Keywords

    • Galaxies: active
    • Gamma rays: observations
    • Quasars: individual

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    Abdo, A. A., Ackermann, M., Ajello, M., Atwood, W. B., Axelsson, M., Baldini, L., ... Ziegler, M. (2009). Early fermi gamma-ray space telescope observations of the quasar 3c 454.3. Astrophysical Journal, 699(1), 817-823. https://doi.org/10.1088/0004-637X/699/1/817

    Early fermi gamma-ray space telescope observations of the quasar 3c 454.3. / Abdo, A. A.; Ackermann, M.; Ajello, M.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Battelino, M.; Baughman, B. M.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Burnett, T. H.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cavazzuti, E.; Cecchi, C.; Charles, E.; Chaty, S.; Chekhtman, A.; Cheung, C. C.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Cominsky, L. R.; Conrad, J.; Costamante, L.; Cutini, S.; Dermer, C. D.; De Angelis, A.; De Palma, F.; Digel, S. W.; Silva, E. Do Couto E; Donato, D.; Drell, P. S.; Dubois, R.; Dumora, D.; Farnier, C.; Favuzzi, C.; Focke, W. B.; Foschini, L.; Frailis, M.; Fuhrmann, L.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giebels, B.; Giglietto, N.; Giommi, P.; Giordano, F.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grondin, M. H.; Grove, J. E.; Guillemot, L.; Guiriec, S.; Hanabata, Y.; Harding, A. K.; Hartman, R. C.; Hayashida, M.; Hays, E.; Hughes, R. E.; Jóhannesson, G.; Johnson, A. S.; Johnson, R. P.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, Jun; Kawai, N.; Kerr, M.; Knödlseder, J.; Kocian, M. L.; Kuehn, F.; Kuss, M.; Latronico, L.; Lee, S. H.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Madejski, G. M.; Makeev, A.; Massaro, E.; Mazziotta, M. N.; McEnery, J. E.; McGlynn, S.; Meurer, C.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Paneque, D.; Panetta, J. H.; Parent, D.; Pelassa, V.; Pepe, M.; Pesce-Rollins, M.; Piron, F.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Reposeur, T.; Reyes, L. C.; Ritz, S.; Rochester, L. S.; Rodriguez, A. Y.; Rahoui, F.; Ryde, F.; Sadrozinski, H. F W; Sambruna, R.; Sanchez, D.; Sander, A.; Parkinson, P. M Saz; Sgrò, C.; Shaw, M. S.; Smith, D. A.; Smith, P. D.; Spandre, G.; Spinelli, P.; Starck, J. L.; Strickman, M. S.; Suson, D. J.; Tajima, H.; Takahashi, H.; Takahashi, T.; Tanaka, T.; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Torres, D. F.; Tosti, G.; Tramacere, A.; Uchiyama, Y.; Usher, T. L.; Vilchez, N.; Villata, M.; Vitale, V.; Waite, A. P.; Winer, B. L.; Wood, K. S.; Ylinen, T.; Zensus, J. A.; Ziegler, M.

    In: Astrophysical Journal, Vol. 699, No. 1, 2009, p. 817-823.

    Research output: Contribution to journalArticle

    Abdo, AA, Ackermann, M, Ajello, M, Atwood, WB, Axelsson, M, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Battelino, M, Baughman, BM, Bechtol, K, Bellazzini, R, Berenji, B, Blandford, RD, Bloom, ED, Bonamente, E, Borgland, AW, Bouvier, A, Bregeon, J, Brez, A, Brigida, M, Bruel, P, Burnett, TH, Caliandro, GA, Cameron, RA, Caraveo, PA, Casandjian, JM, Cavazzuti, E, Cecchi, C, Charles, E, Chaty, S, Chekhtman, A, Cheung, CC, Chiang, J, Ciprini, S, Claus, R, Cohen-Tanugi, J, Cominsky, LR, Conrad, J, Costamante, L, Cutini, S, Dermer, CD, De Angelis, A, De Palma, F, Digel, SW, Silva, EDCE, Donato, D, Drell, PS, Dubois, R, Dumora, D, Farnier, C, Favuzzi, C, Focke, WB, Foschini, L, Frailis, M, Fuhrmann, L, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Gehrels, N, Germani, S, Giebels, B, Giglietto, N, Giommi, P, Giordano, F, Glanzman, T, Godfrey, G, Grenier, IA, Grondin, MH, Grove, JE, Guillemot, L, Guiriec, S, Hanabata, Y, Harding, AK, Hartman, RC, Hayashida, M, Hays, E, Hughes, RE, Jóhannesson, G, Johnson, AS, Johnson, RP, Johnson, WN, Kamae, T, Katagiri, H, Kataoka, J, Kawai, N, Kerr, M, Knödlseder, J, Kocian, ML, Kuehn, F, Kuss, M, Latronico, L, Lee, SH, Lemoine-Goumard, M, Longo, F, Loparco, F, Lott, B, Lovellette, MN, Lubrano, P, Madejski, GM, Makeev, A, Massaro, E, Mazziotta, MN, McEnery, JE, McGlynn, S, Meurer, C, Michelson, PF, Mitthumsiri, W, Mizuno, T, Moiseev, AA, Monte, C, Monzani, ME, Morselli, A, Moskalenko, IV, Murgia, S, Nolan, PL, Norris, JP, Nuss, E, Ohsugi, T, Omodei, N, Orlando, E, Ormes, JF, Paneque, D, Panetta, JH, Parent, D, Pelassa, V, Pepe, M, Pesce-Rollins, M, Piron, F, Porter, TA, Rainò, S, Rando, R, Razzano, M, Reimer, A, Reimer, O, Reposeur, T, Reyes, LC, Ritz, S, Rochester, LS, Rodriguez, AY, Rahoui, F, Ryde, F, Sadrozinski, HFW, Sambruna, R, Sanchez, D, Sander, A, Parkinson, PMS, Sgrò, C, Shaw, MS, Smith, DA, Smith, PD, Spandre, G, Spinelli, P, Starck, JL, Strickman, MS, Suson, DJ, Tajima, H, Takahashi, H, Takahashi, T, Tanaka, T, Thayer, JB, Thayer, JG, Thompson, DJ, Tibaldo, L, Torres, DF, Tosti, G, Tramacere, A, Uchiyama, Y, Usher, TL, Vilchez, N, Villata, M, Vitale, V, Waite, AP, Winer, BL, Wood, KS, Ylinen, T, Zensus, JA & Ziegler, M 2009, 'Early fermi gamma-ray space telescope observations of the quasar 3c 454.3', Astrophysical Journal, vol. 699, no. 1, pp. 817-823. https://doi.org/10.1088/0004-637X/699/1/817
    Abdo AA, Ackermann M, Ajello M, Atwood WB, Axelsson M, Baldini L et al. Early fermi gamma-ray space telescope observations of the quasar 3c 454.3. Astrophysical Journal. 2009;699(1):817-823. https://doi.org/10.1088/0004-637X/699/1/817
    Abdo, A. A. ; Ackermann, M. ; Ajello, M. ; Atwood, W. B. ; Axelsson, M. ; Baldini, L. ; Ballet, J. ; Barbiellini, G. ; Bastieri, D. ; Battelino, M. ; Baughman, B. M. ; Bechtol, K. ; Bellazzini, R. ; Berenji, B. ; Blandford, R. D. ; Bloom, E. D. ; Bonamente, E. ; Borgland, A. W. ; Bouvier, A. ; Bregeon, J. ; Brez, A. ; Brigida, M. ; Bruel, P. ; Burnett, T. H. ; Caliandro, G. A. ; Cameron, R. A. ; Caraveo, P. A. ; Casandjian, J. M. ; Cavazzuti, E. ; Cecchi, C. ; Charles, E. ; Chaty, S. ; Chekhtman, A. ; Cheung, C. C. ; Chiang, J. ; Ciprini, S. ; Claus, R. ; Cohen-Tanugi, J. ; Cominsky, L. R. ; Conrad, J. ; Costamante, L. ; Cutini, S. ; Dermer, C. D. ; De Angelis, A. ; De Palma, F. ; Digel, S. W. ; Silva, E. Do Couto E ; Donato, D. ; Drell, P. S. ; Dubois, R. ; Dumora, D. ; Farnier, C. ; Favuzzi, C. ; Focke, W. B. ; Foschini, L. ; Frailis, M. ; Fuhrmann, L. ; Fukazawa, Y. ; Funk, S. ; Fusco, P. ; Gargano, F. ; Gasparrini, D. ; Gehrels, N. ; Germani, S. ; Giebels, B. ; Giglietto, N. ; Giommi, P. ; Giordano, F. ; Glanzman, T. ; Godfrey, G. ; Grenier, I. A. ; Grondin, M. H. ; Grove, J. E. ; Guillemot, L. ; Guiriec, S. ; Hanabata, Y. ; Harding, A. K. ; Hartman, R. C. ; Hayashida, M. ; Hays, E. ; Hughes, R. E. ; Jóhannesson, G. ; Johnson, A. S. ; Johnson, R. P. ; Johnson, W. N. ; Kamae, T. ; Katagiri, H. ; Kataoka, Jun ; Kawai, N. ; Kerr, M. ; Knödlseder, J. ; Kocian, M. L. ; Kuehn, F. ; Kuss, M. ; Latronico, L. ; Lee, S. H. ; Lemoine-Goumard, M. ; Longo, F. ; Loparco, F. ; Lott, B. ; Lovellette, M. N. ; Lubrano, P. ; Madejski, G. M. ; Makeev, A. ; Massaro, E. ; Mazziotta, M. N. ; McEnery, J. E. ; McGlynn, S. ; Meurer, C. ; Michelson, P. F. ; Mitthumsiri, W. ; Mizuno, T. ; Moiseev, A. A. ; Monte, C. ; Monzani, M. E. ; Morselli, A. ; Moskalenko, I. V. ; Murgia, S. ; Nolan, P. L. ; Norris, J. P. ; Nuss, E. ; Ohsugi, T. ; Omodei, N. ; Orlando, E. ; Ormes, J. F. ; Paneque, D. ; Panetta, J. H. ; Parent, D. ; Pelassa, V. ; Pepe, M. ; Pesce-Rollins, M. ; Piron, F. ; Porter, T. A. ; Rainò, S. ; Rando, R. ; Razzano, M. ; Reimer, A. ; Reimer, O. ; Reposeur, T. ; Reyes, L. C. ; Ritz, S. ; Rochester, L. S. ; Rodriguez, A. Y. ; Rahoui, F. ; Ryde, F. ; Sadrozinski, H. F W ; Sambruna, R. ; Sanchez, D. ; Sander, A. ; Parkinson, P. M Saz ; Sgrò, C. ; Shaw, M. S. ; Smith, D. A. ; Smith, P. D. ; Spandre, G. ; Spinelli, P. ; Starck, J. L. ; Strickman, M. S. ; Suson, D. J. ; Tajima, H. ; Takahashi, H. ; Takahashi, T. ; Tanaka, T. ; Thayer, J. B. ; Thayer, J. G. ; Thompson, D. J. ; Tibaldo, L. ; Torres, D. F. ; Tosti, G. ; Tramacere, A. ; Uchiyama, Y. ; Usher, T. L. ; Vilchez, N. ; Villata, M. ; Vitale, V. ; Waite, A. P. ; Winer, B. L. ; Wood, K. S. ; Ylinen, T. ; Zensus, J. A. ; Ziegler, M. / Early fermi gamma-ray space telescope observations of the quasar 3c 454.3. In: Astrophysical Journal. 2009 ; Vol. 699, No. 1. pp. 817-823.
    @article{0c7b621b3dab4c25979245ab86c57c03,
    title = "Early fermi gamma-ray space telescope observations of the quasar 3c 454.3",
    abstract = "This is the first report of Fermi Gamma-Ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope, covering 2008 July 7-October 6, indicate strong, highly variable γ-ray emission with an average flux of 3 × 10-6 photons cm-2 s-1, for energies >100 MeV. The γ-ray flux is variable, with strong, distinct, symmetrically shaped flares for which the flux increases by a factor of several on a timescale of about 3 days. This variability indicates a compact emission region, and the requirement that the source is optically thin to pair production implies relativistic beaming with Doppler factor δ>8, consistent with the values inferred from Very Long Baseline Interferometry observations of superluminal expansion (δ 25). The observed γ-ray spectrum is not consistent with a simple power law, but instead steepens strongly above 2 GeV, and is well described by a broken power law with photon indices of 2.3 and 3.5 below and above the break, respectively. This is the first direct observation of a break in the spectrum of a high-luminosity blazar above 100 MeV, and it is likely direct evidence for an intrinsic break in the energy distribution of the radiating particles. Alternatively, the spectral softening above 2GeV could be due to γ-ray absorption via photon-photon pair production on the soft X-ray photon field of the host active galactic nucleus, but such an interpretation would require the dissipation region to be located very close (≲100 gravitational radii) to the black hole, which would be inconsistent with the X-ray spectrum of the source.",
    keywords = "Galaxies: active, Gamma rays: observations, Quasars: individual",
    author = "Abdo, {A. A.} and M. Ackermann and M. Ajello and Atwood, {W. B.} and M. Axelsson and L. Baldini and J. Ballet and G. Barbiellini and D. Bastieri and M. Battelino and Baughman, {B. M.} and K. Bechtol and R. Bellazzini and B. Berenji and Blandford, {R. D.} and Bloom, {E. D.} and E. Bonamente and Borgland, {A. W.} and A. Bouvier and J. Bregeon and A. Brez and M. Brigida and P. Bruel and Burnett, {T. H.} and Caliandro, {G. A.} and Cameron, {R. A.} and Caraveo, {P. A.} and Casandjian, {J. M.} and E. Cavazzuti and C. Cecchi and E. Charles and S. Chaty and A. Chekhtman and Cheung, {C. C.} and J. Chiang and S. Ciprini and R. Claus and J. Cohen-Tanugi and Cominsky, {L. R.} and J. Conrad and L. Costamante and S. Cutini and Dermer, {C. D.} and {De Angelis}, A. and {De Palma}, F. and Digel, {S. W.} and Silva, {E. Do Couto E} and D. Donato and Drell, {P. S.} and R. Dubois and D. Dumora and C. Farnier and C. Favuzzi and Focke, {W. B.} and L. Foschini and M. Frailis and L. Fuhrmann and Y. Fukazawa and S. Funk and P. Fusco and F. Gargano and D. Gasparrini and N. Gehrels and S. Germani and B. Giebels and N. Giglietto and P. Giommi and F. Giordano and T. Glanzman and G. Godfrey and Grenier, {I. A.} and Grondin, {M. H.} and Grove, {J. E.} and L. Guillemot and S. Guiriec and Y. Hanabata and Harding, {A. K.} and Hartman, {R. C.} and M. Hayashida and E. Hays and Hughes, {R. E.} and G. J{\'o}hannesson and Johnson, {A. S.} and Johnson, {R. P.} and Johnson, {W. N.} and T. Kamae and H. Katagiri and Jun Kataoka and N. Kawai and M. Kerr and J. Kn{\"o}dlseder and Kocian, {M. L.} and F. Kuehn and M. Kuss and L. Latronico and Lee, {S. H.} and M. Lemoine-Goumard and F. Longo and F. Loparco and B. Lott and Lovellette, {M. N.} and P. Lubrano and Madejski, {G. M.} and A. Makeev and E. Massaro and Mazziotta, {M. N.} and McEnery, {J. E.} and S. McGlynn and C. Meurer and Michelson, {P. F.} and W. Mitthumsiri and T. Mizuno and Moiseev, {A. A.} and C. Monte and Monzani, {M. E.} and A. Morselli and Moskalenko, {I. V.} and S. Murgia and Nolan, {P. L.} and Norris, {J. P.} and E. Nuss and T. Ohsugi and N. Omodei and E. Orlando and Ormes, {J. F.} and D. Paneque and Panetta, {J. H.} and D. Parent and V. Pelassa and M. Pepe and M. Pesce-Rollins and F. Piron and Porter, {T. A.} and S. Rain{\`o} and R. Rando and M. Razzano and A. Reimer and O. Reimer and T. Reposeur and Reyes, {L. C.} and S. Ritz and Rochester, {L. S.} and Rodriguez, {A. Y.} and F. Rahoui and F. Ryde and Sadrozinski, {H. F W} and R. Sambruna and D. Sanchez and A. Sander and Parkinson, {P. M Saz} and C. Sgr{\`o} and Shaw, {M. S.} and Smith, {D. A.} and Smith, {P. D.} and G. Spandre and P. Spinelli and Starck, {J. L.} and Strickman, {M. S.} and Suson, {D. J.} and H. Tajima and H. Takahashi and T. Takahashi and T. Tanaka and Thayer, {J. B.} and Thayer, {J. G.} and Thompson, {D. J.} and L. Tibaldo and Torres, {D. F.} and G. Tosti and A. Tramacere and Y. Uchiyama and Usher, {T. L.} and N. Vilchez and M. Villata and V. Vitale and Waite, {A. P.} and Winer, {B. L.} and Wood, {K. S.} and T. Ylinen and Zensus, {J. A.} and M. Ziegler",
    year = "2009",
    doi = "10.1088/0004-637X/699/1/817",
    language = "English",
    volume = "699",
    pages = "817--823",
    journal = "Astrophysical Journal",
    issn = "0004-637X",
    publisher = "IOP Publishing Ltd.",
    number = "1",

    }

    TY - JOUR

    T1 - Early fermi gamma-ray space telescope observations of the quasar 3c 454.3

    AU - Abdo, A. A.

    AU - Ackermann, M.

    AU - Ajello, M.

    AU - Atwood, W. B.

    AU - Axelsson, M.

    AU - Baldini, L.

    AU - Ballet, J.

    AU - Barbiellini, G.

    AU - Bastieri, D.

    AU - Battelino, M.

    AU - Baughman, B. M.

    AU - Bechtol, K.

    AU - Bellazzini, R.

    AU - Berenji, B.

    AU - Blandford, R. D.

    AU - Bloom, E. D.

    AU - Bonamente, E.

    AU - Borgland, A. W.

    AU - Bouvier, A.

    AU - Bregeon, J.

    AU - Brez, A.

    AU - Brigida, M.

    AU - Bruel, P.

    AU - Burnett, T. H.

    AU - Caliandro, G. A.

    AU - Cameron, R. A.

    AU - Caraveo, P. A.

    AU - Casandjian, J. M.

    AU - Cavazzuti, E.

    AU - Cecchi, C.

    AU - Charles, E.

    AU - Chaty, S.

    AU - Chekhtman, A.

    AU - Cheung, C. C.

    AU - Chiang, J.

    AU - Ciprini, S.

    AU - Claus, R.

    AU - Cohen-Tanugi, J.

    AU - Cominsky, L. R.

    AU - Conrad, J.

    AU - Costamante, L.

    AU - Cutini, S.

    AU - Dermer, C. D.

    AU - De Angelis, A.

    AU - De Palma, F.

    AU - Digel, S. W.

    AU - Silva, E. Do Couto E

    AU - Donato, D.

    AU - Drell, P. S.

    AU - Dubois, R.

    AU - Dumora, D.

    AU - Farnier, C.

    AU - Favuzzi, C.

    AU - Focke, W. B.

    AU - Foschini, L.

    AU - Frailis, M.

    AU - Fuhrmann, L.

    AU - Fukazawa, Y.

    AU - Funk, S.

    AU - Fusco, P.

    AU - Gargano, F.

    AU - Gasparrini, D.

    AU - Gehrels, N.

    AU - Germani, S.

    AU - Giebels, B.

    AU - Giglietto, N.

    AU - Giommi, P.

    AU - Giordano, F.

    AU - Glanzman, T.

    AU - Godfrey, G.

    AU - Grenier, I. A.

    AU - Grondin, M. H.

    AU - Grove, J. E.

    AU - Guillemot, L.

    AU - Guiriec, S.

    AU - Hanabata, Y.

    AU - Harding, A. K.

    AU - Hartman, R. C.

    AU - Hayashida, M.

    AU - Hays, E.

    AU - Hughes, R. E.

    AU - Jóhannesson, G.

    AU - Johnson, A. S.

    AU - Johnson, R. P.

    AU - Johnson, W. N.

    AU - Kamae, T.

    AU - Katagiri, H.

    AU - Kataoka, Jun

    AU - Kawai, N.

    AU - Kerr, M.

    AU - Knödlseder, J.

    AU - Kocian, M. L.

    AU - Kuehn, F.

    AU - Kuss, M.

    AU - Latronico, L.

    AU - Lee, S. H.

    AU - Lemoine-Goumard, M.

    AU - Longo, F.

    AU - Loparco, F.

    AU - Lott, B.

    AU - Lovellette, M. N.

    AU - Lubrano, P.

    AU - Madejski, G. M.

    AU - Makeev, A.

    AU - Massaro, E.

    AU - Mazziotta, M. N.

    AU - McEnery, J. E.

    AU - McGlynn, S.

    AU - Meurer, C.

    AU - Michelson, P. F.

    AU - Mitthumsiri, W.

    AU - Mizuno, T.

    AU - Moiseev, A. A.

    AU - Monte, C.

    AU - Monzani, M. E.

    AU - Morselli, A.

    AU - Moskalenko, I. V.

    AU - Murgia, S.

    AU - Nolan, P. L.

    AU - Norris, J. P.

    AU - Nuss, E.

    AU - Ohsugi, T.

    AU - Omodei, N.

    AU - Orlando, E.

    AU - Ormes, J. F.

    AU - Paneque, D.

    AU - Panetta, J. H.

    AU - Parent, D.

    AU - Pelassa, V.

    AU - Pepe, M.

    AU - Pesce-Rollins, M.

    AU - Piron, F.

    AU - Porter, T. A.

    AU - Rainò, S.

    AU - Rando, R.

    AU - Razzano, M.

    AU - Reimer, A.

    AU - Reimer, O.

    AU - Reposeur, T.

    AU - Reyes, L. C.

    AU - Ritz, S.

    AU - Rochester, L. S.

    AU - Rodriguez, A. Y.

    AU - Rahoui, F.

    AU - Ryde, F.

    AU - Sadrozinski, H. F W

    AU - Sambruna, R.

    AU - Sanchez, D.

    AU - Sander, A.

    AU - Parkinson, P. M Saz

    AU - Sgrò, C.

    AU - Shaw, M. S.

    AU - Smith, D. A.

    AU - Smith, P. D.

    AU - Spandre, G.

    AU - Spinelli, P.

    AU - Starck, J. L.

    AU - Strickman, M. S.

    AU - Suson, D. J.

    AU - Tajima, H.

    AU - Takahashi, H.

    AU - Takahashi, T.

    AU - Tanaka, T.

    AU - Thayer, J. B.

    AU - Thayer, J. G.

    AU - Thompson, D. J.

    AU - Tibaldo, L.

    AU - Torres, D. F.

    AU - Tosti, G.

    AU - Tramacere, A.

    AU - Uchiyama, Y.

    AU - Usher, T. L.

    AU - Vilchez, N.

    AU - Villata, M.

    AU - Vitale, V.

    AU - Waite, A. P.

    AU - Winer, B. L.

    AU - Wood, K. S.

    AU - Ylinen, T.

    AU - Zensus, J. A.

    AU - Ziegler, M.

    PY - 2009

    Y1 - 2009

    N2 - This is the first report of Fermi Gamma-Ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope, covering 2008 July 7-October 6, indicate strong, highly variable γ-ray emission with an average flux of 3 × 10-6 photons cm-2 s-1, for energies >100 MeV. The γ-ray flux is variable, with strong, distinct, symmetrically shaped flares for which the flux increases by a factor of several on a timescale of about 3 days. This variability indicates a compact emission region, and the requirement that the source is optically thin to pair production implies relativistic beaming with Doppler factor δ>8, consistent with the values inferred from Very Long Baseline Interferometry observations of superluminal expansion (δ 25). The observed γ-ray spectrum is not consistent with a simple power law, but instead steepens strongly above 2 GeV, and is well described by a broken power law with photon indices of 2.3 and 3.5 below and above the break, respectively. This is the first direct observation of a break in the spectrum of a high-luminosity blazar above 100 MeV, and it is likely direct evidence for an intrinsic break in the energy distribution of the radiating particles. Alternatively, the spectral softening above 2GeV could be due to γ-ray absorption via photon-photon pair production on the soft X-ray photon field of the host active galactic nucleus, but such an interpretation would require the dissipation region to be located very close (≲100 gravitational radii) to the black hole, which would be inconsistent with the X-ray spectrum of the source.

    AB - This is the first report of Fermi Gamma-Ray Space Telescope observations of the quasar 3C 454.3, which has been undergoing pronounced long-term outbursts since 2000. The data from the Large Area Telescope, covering 2008 July 7-October 6, indicate strong, highly variable γ-ray emission with an average flux of 3 × 10-6 photons cm-2 s-1, for energies >100 MeV. The γ-ray flux is variable, with strong, distinct, symmetrically shaped flares for which the flux increases by a factor of several on a timescale of about 3 days. This variability indicates a compact emission region, and the requirement that the source is optically thin to pair production implies relativistic beaming with Doppler factor δ>8, consistent with the values inferred from Very Long Baseline Interferometry observations of superluminal expansion (δ 25). The observed γ-ray spectrum is not consistent with a simple power law, but instead steepens strongly above 2 GeV, and is well described by a broken power law with photon indices of 2.3 and 3.5 below and above the break, respectively. This is the first direct observation of a break in the spectrum of a high-luminosity blazar above 100 MeV, and it is likely direct evidence for an intrinsic break in the energy distribution of the radiating particles. Alternatively, the spectral softening above 2GeV could be due to γ-ray absorption via photon-photon pair production on the soft X-ray photon field of the host active galactic nucleus, but such an interpretation would require the dissipation region to be located very close (≲100 gravitational radii) to the black hole, which would be inconsistent with the X-ray spectrum of the source.

    KW - Galaxies: active

    KW - Gamma rays: observations

    KW - Quasars: individual

    UR - http://www.scopus.com/inward/record.url?scp=68049148115&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=68049148115&partnerID=8YFLogxK

    U2 - 10.1088/0004-637X/699/1/817

    DO - 10.1088/0004-637X/699/1/817

    M3 - Article

    AN - SCOPUS:68049148115

    VL - 699

    SP - 817

    EP - 823

    JO - Astrophysical Journal

    JF - Astrophysical Journal

    SN - 0004-637X

    IS - 1

    ER -