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Fermi/Large Area Telescope Discovery of Gamma-Ray Emission from a Relativistic Jet in the Narrow-Line Quasar PMN J0948+0022 (2009) |
- 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.,
- Caliandro, G. A.,
- Cameron, R. A.,
- Caraveo, P. A.,
- Casadjian, J. M,
- Cavazzuti, E.,
- Cecchi, C.,
- Chekhtman, A.,
- Cheung, C. C.,
- Chiang, J.,
- Ciprini, S.,
- Claus, R.,
- Cohen-Tanugi, J.,
- Collmar, W.,
- Conrad, J,
- Costamante, L.,
- Dermer, C. D.,
- De Angelis, A.,
- De Palma, F.,
- Digel, S. W.,
- 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.,
- Gehrels, N.,
- Germani, S.,
- Giebels, B.,
- Giglietto, N.,
- Giordano, F.,
- Giroletti, M.,
- Glanzman, T.,
- Grenier, I. A.,
- 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, W. N.,
- Kamae, T.,
- Katagiri, H,
- Kataoka, F.,
- Kerr, M.,
- Knödlseder, J.,
- Kuehn, F.,
- Kuss, M.,
- Lande, J.,
- Latronico, L.,
- Lemoine-Goumard, M.,
- Longo, F.,
- Loparco, F.,
- Lott, B.,
- Lovellette, M. N.,
- Lubrano, P.,
- Madejski, G. M.,
- Makeev, A.,
- Max-Moerbeck, W.,
- Mazziotta, M. N.,
- McConville, W.,
- McEnery, J. E.,
- Meurer, C.,
- Michelson, P. F.,
- Mitthumsiri, W.,
- Mizuno, T.,
- 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.,
- Pavlidou, V.,
- Pearson, T. J.,
- Pepe, M.,
- Pesce-Rollins, M.,
- Piron, F.,
- Porter, T. A.,
- Rainò, S.,
- Rando, R.,
- Razzano, M.,
- Readhead, A.,
- Reimer, A.,
- Reimer, O.,
- Reposeur, T.,
- Richards, J. L.,
- Ritz, S.,
- Rodriguez, A. Y.,
- Romani, R. W.,
- Ryde, F.,
- Sadrozinski, H. F. -W.,
- Sambruna, R.,
- Sanchez, D.,
- Sander, A.,
- Saz Parkinson, P. M.,
- Scargle, J. D.,
- Schalk, T. L.,
- Sgrò, C.,
- Smith, D. A.,
- Spandre, G.,
- Spinelli, P.,
- Stevenson, M.,
- Strickman, M. S.,
- Suson, D. J.,
- Tagliaferri, G.,
- Takahashi, H.,
- Tanaka, T.,
- Thayer, J. G.,
- Thompson, D. J.,
- Tibaldo, L.,
- Tibolla, O.,
- Torres, D. F.,
- Tosti, G.,
- Tramacere, A.,
- Uchiyama, Y.,
- Usher, T. L.,
- Vilchez, N.,
- Vitale, V.,
- Waite, A. P.,
- Winer, B. L.,
- Wood, K. S.,
- Ylinen, Y.,
- Zensus, J. A.,
- Ziegler, M.
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Abstract |
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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. |
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