Fermi Large Area Telescope Observations of Misaligned AGN

A. A. Abdo , Markus Ackermann , Marco Ajello , Luca Baldini , Jean Ballet (1) , Guido Barbiellini , D. Bastieri , K. Bechtol , R. Bellazzini , B. Berenji , R. D. Blandford , E. D. Bloom , E. Bonamente , A. W. Borgland , A. Bouvier , T. J. Brandt , J. Bregeon , A. Brez , M. Brigida , Pascal Bruel (2) , R. Buehler , T. H. Burnett , S. Buson , G. A. Caliandro , R. A. Cameron , A. Cannon , P. A. Caraveo , S. Carrigan , J. M. Casandjian (1) , E. Cavazzuti , C. Cecchi , O. Celik , A. Celotti , E. Charles , A. Chekhtman , A. W. Chen , C. C. Cheung , J. Chiang , S. Ciprini , R. Claus , J. Cohen-Tanugi (3) , S. Colafrancesco , J. Conrad , D. S. Davis , C. D. Dermer , A. de Angelis , F. de Palma , E. Do Couto E Silva , P. S. Drell , R. Dubois , C. Favuzzi , S. J. Fegan (2) , E. C. Ferrara , P. Fortin (2) , M. Frailis , Y. Fukazawa , P. Fusco , F. Gargano , D. Gasparrini , N. Gehrels , S. Germani , N. Giglietto , P. Giommi , F. Giordano , M. Giroletti , T. Glanzman , G. Godfrey , P. Grandi , I. A. Grenier (1) , J. E. Grove , L. Guillemot (4) , S. Guiriec , D. Hadasch , M. Hayashida , E. Hays , D. Horan (2) , R. E. Hughes , M. S. Jackson , G. Johannesson , A. S. Johnson , W. N. Johnson , T. Kamae , H. Katagiri , J. Kataoka , Jürgen Knödlseder (5) , M. Kuss , J. Lande , L. Latronico , S.-H. Lee , M. Lemoine-Goumard (4) , M. Llena Garde , F. Longo , F. Loparco , B. Lott (4) , M. N. Lovellette , P. Lubrano , G. M. Madejski , A. Makeev , G. Malaguti , M. N. Mazziotta , W. Mcconville , J. E. Mcenery , P. F. Michelson , G. Migliori , W. Mitthumsiri , T. Mizuno , C. Monte , M. E. Monzani , A. Morselli , I. V. Moskalenko , S. Murgia , M. Naumann-Godo , I. Nestoras , P. L. Nolan , J. P. Norris , E. Nuss (3) , T. Ohsugi , A. Okumura , N. Omodei , E. Orlando , J. F. Ormes , D. Paneque , J. H. Panetta , D. Parent (4) , V. Pelassa (3) , M. Pepe , M. Persic , M. Pesce-Rollins , F. Piron (3) , T.A. Porter , S. Raino , R. Rando , M. Razzano , S. Razzaque , A. Reimer , O. Reimer , L. C. Reyes , M. Roth , H. F.-W. Sadrozinski , D. Sanchez (2) , A. Sander , J. D. Scargle , C. Sgro , E. J. Siskind , P. D. Smith , G. Spandre , P. Spinelli , Ł. Stawarz , F. W. Stecker , M. S. Strickman , D. J. Suson , H. Takahashi , T. Tanaka , J. B. Thayer , J. G. Thayer , D. J. Thompson , L. Tibaldo (1) , D. F. Torres , E. Torresi , G. Tosti , A. Tramacere , Y. Uchiyama , T. L. Usher , J. Vandenbroucke , V. Vasileiou , N. Vilchez (5) , M. Villata , V. Vitale , A. P. Waite , P. Wang , B. L. Winer , K. S. Wood , Z. Yang , T. Ylinen , M. Ziegler

1 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
2 LLR - Laboratoire Leprince-Ringuet
3 LPTA - Laboratoire de Physique Théorique et Astroparticules
4 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan
5 CESR - Centre d'étude spatiale des rayonnements

Analysis is presented on 15 months of data taken with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope for 11 non-blazar AGNs, including 7 FRI radio galaxies and 4 FRII radio sources consisting of 2 FRII radio galaxies and 2 steep spectrum radio quasars. The broad line FRI radio galaxy 3C 120 is reported here as a gamma-ray source for the first time. The analysis is based on directional associations of LAT sources with radio sources in the 3CR, 3CRR and MS4 (collectively referred to as 3C-MS) catalogs. Seven of the eleven LAT sources associated with 3C-MS radio sources have spectral indices larger than 2.3 and, except for the FRI radio galaxy NGC 1275 that shows possible spectral curvature, are well described by a power law. No evidence for time variability is found for any sources other than NGC 1275. The gamma-ray luminosities of FRI radio galaxies are significantly smaller than those of BL Lac objects detected by the LAT, whereas the gamma-ray luminosities of FRII sources are quite similar to those of FSRQs, which could reflect different beaming factors for the gamma-ray emission. A core dominance study of the 3CRR sample indicate that sources closer to the jet axis are preferentially detected with the Fermi-LAT, insofar as the gamma-ray--detected misaligned AGNs have larger core dominance at a given average radio flux. The results are discussed in view of the AGN unification scenario.

Mots clés: galaxies: active; galaxies: jets; gamma rays: general

Domaines: Phénomènes cosmiques de haute energie [astro-ph.HE]; Phénomènes cosmiques de haute energie [astro-ph.HE]

A. A. Abdo, Markus Ackermann, Marco Ajello, Luca Baldini, Jean Ballet, et al.. Fermi Large Area Telescope Observations of Misaligned AGN. The Astrophysical Journal, 2010, 720, pp.912-922. ⟨10.1088/0004-637X/720/1/912⟩. ⟨in2p3-00530049⟩