Multiwavelength Evidence for Quasi-periodic Modulation in the Gamma-ray Blazar PG 1553+113

M. Ackermann , M. Ajello , A. Albert , W.B. Atwood , L. Baldini , J. Ballet (1) , G. Barbiellini , D. Bastieri , J. Becerra Gonzalez , R. Bellazzini , E. Bissaldi , R.D. Blandford , E.D. Bloom , R. Bonino , E. Bottacini , J. Bregeon (2) , P. Bruel (3) , R. Buehler , S. Buson , G.A. Caliandro , R.A. Cameron , R. Caputo , M. Caragiulo , P.A. Caraveo , E. Cavazzuti , C. Cecchi , A. Chekhtman , J. Chiang , G. Chiaro , S. Ciprini , Johann Cohen-Tanugi (2) , J. Conrad , S. Cutini , F. d'Ammando , A. de Angelis , F. de Palma , R. Desiante , L. Di Venere , A. Domínguez , P.S. Drell , C. Favuzzi , S.J. Fegan (3) , E.C. Ferrara , W.B. Focke , L. Fuhrmann , Y. Fukazawa , P. Fusco , F. Gargano , D. Gasparrini , N. Giglietto , P. Giommi , F. Giordano , M. Giroletti , G. Godfrey , D. Green , I.A. Grenier (1) , J.E. Grove , S. Guiriec , A.K. Harding , E. Hays , J.W. Hewitt , A.B. Hill , D. Horan (3) , T. Jogler , G. Jóhannesson , A.S. Johnson , T. Kamae , M. Kuss , S. Larsson , L. Latronico , J. Li , L. Li , F. Longo , F. Loparco , B. Lott (4) , M.N. Lovellette , P. Lubrano , J. Magill , S. Maldera , A. Manfreda , W. Max-Moerbeck , M. Mayer , M.N. Mazziotta , J.E. Mcenery , P.F. Michelson , T. Mizuno , M.E. Monzani , A. Morselli , I.V. Moskalenko , S. Murgia , E. Nuss (2) , M. Ohno , T. Ohsugi , R. Ojha , N. Omodei , E. Orlando , J.F. Ormes , D. Paneque , T.J. Pearson , J.S. Perkins , M. Perri , M. Pesce-Rollins , V. Petrosian , F. Piron (2) , G. Pivato , T.A. Porter , S. Rainò , R. Rando , M. Razzano , A. Readhead , A. Reimer , O. Reimer , A. Schulz , C. Sgrò , E.J. Siskind , F. Spada , G. Spandre , P. Spinelli , D.J. Suson , H. Takahashi , J.B. Thayer , D.J. Thompson , L. Tibaldo , D.F. Torres , G. Tosti , E. Troja , Y. Uchiyama , G. Vianello , K.S. Wood , M. Wood , S. Zimmer , A. Berdyugin , R.H.D. Corbet , T. Hovatta , E. Lindfors , K. Nilsson , R. Reinthal , A. Sillanpää , A. Stamerra , L.O. Takalo , M.J. Valtonen

1 AIM (UMR7158 / UMR_E_9005 / UM_112) - Astrophysique Interprétation Modélisation
2 LUPM - Laboratoire Univers et Particules de Montpellier
3 LLR - Laboratoire Leprince-Ringuet
4 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan

We report for the first time a γ-ray and multiwavelength nearly periodic oscillation in an active galactic nucleus. Using the Fermi Large Area Telescope we have discovered an apparent quasi-periodicity in the γ-ray flux (E > 100 MeV) from the GeV/TeV BL Lac object PG 1553+113. The marginal significance of the 2.18 ± 0.08 year period γ-ray cycle is strengthened by correlated oscillations observed in radio and optical fluxes, through data collected in the Owens Valley Radio Observatory, Tuorla, Katzman Automatic Imaging Telescope, and Catalina Sky Survey monitoring programs and Swift-UVOT. The optical cycle appearing in ∼10 years of data has a similar period, while the 15 GHz oscillation is less regular than seen in the other bands. Further long-term multiwavelength monitoring of this blazar may discriminate among the possible explanations for this quasi-periodicity.

Mots clés: accretion; accretion disks; BL Lacertae objects: general; BL Lacertae objects: individual; galaxies: jets; gamma rays: galaxies; gamma rays: general; gamma ray: flux; oscillation; monitoring; optical; blazar; modulation; AGN; GLAST

Domaines: Astrophysique [astro-ph]

M. Ackermann, M. Ajello, A. Albert, W.B. Atwood, L. Baldini, et al.. Multiwavelength Evidence for Quasi-periodic Modulation in the Gamma-ray Blazar PG 1553+113. Astrophys.J.Lett., 2015, 813 (2), pp.L41. ⟨10.1088/2041-8205/813/2/L41⟩. ⟨hal-02017077⟩