Fermi/large area telescope discovery of gamma-ray emission from a relativistic jet in the narrow-line quasar pmn j0948+0022

A. A. Abdo, M. Ackermann, M. Ajello, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, M. Battelino, B. M. Baughman, K. Bechtol, R. Bellazzini, E. D. Bloom, E. Bonamente, A. W. Borgland, J. Bregeon, A. Brez, M. Brigida, P. Bruel, G. A. CaliandroR. A. Cameron, P. A. Caraveo, J. M. Casandjian, E. Cavazzuti, C. Cecchi, A. Chekhtman, C. C. Cheung, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, W. Collmar, J. Conrad, L. Costamante, C. D. Dermer, A. De Angelis, F. De Palma, S. W. Digel, E. Do Couto E Silva, 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, N. Gehrels, S. Germani, B. Giebels, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, 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, M. Kerr, J. Knödlseder, F. Kuehn, M. Kuss, J. Lande, L. Latronico, M. Lemoine-Goumard, F. Longo, F. Loparco, B. Lott, M. N. Lovellette, P. Lubrano, G. M. Madejski, A. Makeev, W. Max-Moerbeck, M. N. Mazziotta, W. McConville, J. E. McEnery, C. Meurer, P. F. Michelson, W. Mitthumsiri, T. Mizuno, 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. Pavlidou, T. J. Pearson, M. Pepe, M. Pesce-Rollins, F. Piron, T. A. Porter, S. Rainò, R. Rando, M. Razzano, A. Readhead, A. Reimer, O. Reimer, T. Reposeur, J. L. Richards, S. Ritz, A. Y. Rodriguez, R. W. Romani, F. Ryde, H. F W Sadrozinski, R. Sambruna, D. Sanchez, A. Sander, P. M Saz Parkinson, J. D. Scargle, T. L. Schalk, C. Sgrò, D. A. Smith, G. Spandre, P. Spinelli, J. L. Starck, M. Stevenson, M. S. Strickman, D. J. Suson, G. Tagliaferri, H. Takahashi, T. Tanaka, J. G. Thayer, D. J. Thompson, L. Tibaldo, O. Tibolla, D. F. Torres, G. Tosti, A. Tramacere, Y. Uchiyama, T. L. Usher, N. Vilchez, V. Vitale, A. P. Waite, B. L. Winer, K. S. Wood, T. Ylinen, J. A. Zensus, M. Ziegler, G. Ghisellini, L. Maraschi, F. Tavecchio, E. Angelakis

    Research output: Contribution to journalArticle

    138 Citations (Scopus)

    Abstract

    We report the discovery by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope of high-energy γ-ray emission from the peculiar quasar PMN J0948+0022 (z = 0.5846). The optical spectrum of this object exhibits rather narrow Hβ (FWHM(Hβ) 1500 km s-1), weak forbidden lines, and is therefore classified as a narrow-line type I quasar. This class of objects is thought to have relatively small black hole mass and to accrete at a high Eddington ratio. The radio loudness and variability of the compact radio core indicate the presence of a relativistic jet. Quasi-simultaneous radio/optical/X-ray and γ-ray observations are presented. Both radio and γ-ray emissions (observed over five months) are strongly variable. The simultaneous optical and X-ray data from Swift show a blue continuum attributed to the accretion disk and a hard X-ray spectrum attributed to the jet. The resulting broadband spectral energy distribution (SED) and, in particular, the γ-ray spectrum measured by Fermi are similar to those of more powerful Flat-Spectrum Radio Quasars (FSRQs). A comparison of the radio and γ-ray characteristics of PMN J0948+0022 with the other blazars detected by LAT shows that this source has a relatively low radio and γ-ray power with respect to other FSRQs. The physical parameters obtained from modeling the SED also fall at the low power end of the FSRQ parameter region discussed in Celotti & Ghisellini. We suggest that the similarity of the SED of PMN J0948+0022 to that of more massive and more powerful quasars can be understood in a scenario in which the SED properties depend on the Eddington ratio rather than on the absolute power.

    Original languageEnglish
    Pages (from-to)976-984
    Number of pages9
    JournalAstrophysical Journal
    Volume699
    Issue number2
    DOIs
    Publication statusPublished - 2009

      Fingerprint

    Keywords

    • Galaxies: active
    • Gamma rays: observations

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    Abdo, A. A., Ackermann, M., Ajello, M., Axelsson, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Battelino, M., Baughman, B. M., Bechtol, K., Bellazzini, R., Bloom, E. D., Bonamente, E., Borgland, A. W., Bregeon, J., Brez, A., Brigida, M., Bruel, P., ... Angelakis, E. (2009). Fermi/large area telescope discovery of gamma-ray emission from a relativistic jet in the narrow-line quasar pmn j0948+0022. Astrophysical Journal, 699(2), 976-984. https://doi.org/10.1088/0004-637X/699/2/976