T
Tatiana S. Konstantinova
Researcher at Saint Petersburg State University
Publications - 66
Citations - 5859
Tatiana S. Konstantinova is an academic researcher from Saint Petersburg State University. The author has contributed to research in topics: Blazar & Light curve. The author has an hindex of 43, co-authored 65 publications receiving 5478 citations.
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Journal ArticleDOI
The spectral energy distribution of fermi bright blazars
A. A. Abdo,A. A. Abdo,Markus Ackermann,Ivan Agudo,Marco Ajello,Hugh D. Aller,Margo F. Aller,Emmanouil Angelakis,A. A. Arkharov,Magnus Axelsson,Magnus Axelsson,Uwe Bach,Luca Baldini,Jean Ballet,Guido Barbiellini,Denis Bastieri,B. M. Baughman,Keith Bechtol,Ronaldo Bellazzini,Erika Benítez,Andrei Berdyugin,B. Berenji,Roger Blandford,E. D. Bloom,Markus Boettcher,Emanuele Bonamente,A. W. Borgland,Johan Bregeon,A. Brez,M. Brigida,P. Bruel,T. H. Burnett,David N. Burrows,S. Buson,G. A. Caliandro,L. Calzoletti,R. A. Cameron,M. Capalbi,P. A. Caraveo,D. Carosati,J. M. Casandjian,E. Cavazzuti,C. Cecchi,Omer Celik,Omer Celik,E. Charles,Sylvain Chaty,A. Chekhtman,A. Chekhtman,Wen Ping Chen,James Chiang,G. Chincarini,Stefano Ciprini,R. Claus,Johann Cohen-Tanugi,S. Colafrancesco,L. R. Cominsky,Jan Conrad,Jan Conrad,L. Costamante,S. Cutini,F. D'Ammando,R. Deitrick,V. D'Elia,Charles D. Dermer,A. De Angelis,F. de Palma,Seth Digel,I. Donnarumma,E. Do Couto E Silva,Persis S. Drell,R. Dubois,Deborah Dultzin,D. Dumora,A. D. Falcone,C. Farnier,C. Favuzzi,S. J. Fegan,W. B. Focke,E. Forné,P. Fortin,Marco Frailis,Lars Fuhrmann,Yasushi Fukazawa,Stefan Funk,P. Fusco,José L. Gómez,F. Gargano,Dario Gasparrini,Neil Gehrels,S. Germani,B. Giebels,Nicola Giglietto,Paolo Giommi,F. Giordano,A. Giuliani,T. Glanzman,G. Godfrey,I. A. Grenier,Caryl Gronwall,J. E. Grove,L. Guillemot,L. Guillemot,Sylvain Guiriec,Mark Gurwell,D. Hadasch,Y. Hanabata,Alice K. Harding,M. Hayashida,E. Hays,S. E. Healey,Jochen Heidt,David Hiriart,D. Horan,E. A. Hoversten,R. E. Hughes,Ryosuke Itoh,Miranda Jackson,Miranda Jackson,Gudlaugur Johannesson,A. S. Johnson,W. N. Johnson,Svetlana G. Jorstad,Matthias Kadler,T. Kamae,Hideaki Katagiri,Jun Kataoka,Nobuyuki Kawai,J. A. Kennea,Matthew Kerr,Givi N. Kimeridze,Jürgen Knödlseder,M. L. Kocian,E. N. Kopatskaya,Ekaterina Koptelova,Tatiana S. Konstantinova,Yuri Y. Kovalev,Yu. A. Kovalev,Omar M. Kurtanidze,M. Kuss,J. Lande,Valeri M. Larionov,Luca Latronico,Paolo Leto,Elina Lindfors,Francesco Longo,F. Loparco,Benoit Lott,M. N. Lovellette,P. Lubrano,Grzegorz Madejski,A. Makeev,A. Makeev,P. Marchegiani,Alan P. Marscher,F. E. Marshall,Walter Max-Moerbeck,M. N. Mazziotta,W. McConville,W. McConville,Julie McEnery,Julie McEnery,C. Meurer,Peter F. Michelson,W. Mitthumsiri,Tsunefumi Mizuno,A. A. Moiseev,A. A. Moiseev,C. Monte,M. E. Monzani,A. Morselli,Igor V. Moskalenko,S. Murgia,I. Nestoras,K. Nilsson,N. A. Nizhelsky,P. L. Nolan,J. P. Norris,E. Nuss,T. Ohsugi,Roopesh Ojha,Nicola Omodei,E. Orlando,Jonathan F. Ormes,J. P. Osborne,M. Ozaki,L. Pacciani,Paolo Padovani,C. Pagani,K. L. Page,David Paneque,J. H. Panetta,D. Parent,M. Pasanen,Vasiliki Pavlidou,V. Pelassa,M. Pepe,M. Perri,Melissa Pesce-Rollins,S. Piranomonte,F. Piron,C. Pittori,T. A. Porter,Simonetta Puccetti,Farid Rahoui,S. Rainò,C. M. Raiteri,Robert R. Rando,M. Razzano,A. Reimer,A. Reimer,Olaf Reimer,Olaf Reimer,T. Reposeur,Joseph L. Richards,Steven Ritz,L.S. Rochester,A. Y. Rodriguez,Roger W. Romani,J. A. Ros,M. Roth,P. Roustazadeh,Felix Ryde,Felix Ryde,H. F.W. Sadrozinski,A. C. Sadun,David Sánchez,A. Sander,P. M. Saz Parkinson,Jeffrey D. Scargle,A. Sellerholm,Carmelo Sgrò,M. S. Shaw,Lorand A. Sigua,E. J. Siskind,David A. Smith,P. D. Smith,Gloria Spandre,P. Spinelli,Jean-Luc Starck,Mark Stevenson,G. Stratta,M. S. Strickman,D. J. Suson,H. Tajima,Hiromitsu Takahashi,Tadayuki Takahashi,L. O. Takalo,Takaaki Tanaka,J. B. Thayer,J. G. Thayer,D. J. Thompson,L. Tibaldo,Diego F. Torres,Gino Tosti,A. Tramacere,A. Tramacere,Yasunobu Uchiyama,T. L. Usher,V. Vasileiou,V. Vasileiou,F. Verrecchia,N. Vilchez,M. Villata,V. Vitale,A. P. Waite,Paul J. Wang,Brian L Winer,K. S. Wood,T. Ylinen,T. Ylinen,J. A. Zensus,G. V. Zhekanis,M. Ziegler +273 more
Abstract: We have conducted a detailed investigation of the broadband spectral properties of the gamma-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated Fermi gamma-ray spectra with Swift, radio, infra-red, optical, and other hard X-ray/gamma-ray data, collected within 3 months of the LBAS data taking period, we were able to assemble high-quality and quasi-simultaneous spectral energy distributions (SED) for 48 LBAS blazars. The SED of these gamma-ray sources is similar to that of blazars discovered at other wavelengths, clearly showing, in the usual log nu-log nu F-nu representation, the typical broadband spectral signatures normally attributed to a combination of low-energy synchrotron radiation followed by inverse Compton emission of one or more components. We have used these SED to characterize the peak intensity of both the low-and the high-energy components. The results have been used to derive empirical relationships that estimate the position of the two peaks from the broadband colors (i.e., the radio to optical, alpha(ro), and optical to X-ray, alpha(ox), spectral slopes) and from the gamma-ray spectral index. Our data show that the synchrotron peak frequency (nu(S)(peak)) is positioned between 10(12.5) and 10(14.5) Hz in broad-lined flat spectrum radio quasars (FSRQs) and between 10(13) and 10(17) Hz in featureless BL Lacertae objects. We find that the gamma-ray spectral slope is strongly correlated with the synchrotron peak energy and with the X-ray spectral index, as expected at first order in synchrotron-inverse Compton scenarios. However, simple homogeneous, one-zone, synchrotron self-Compton (SSC) models cannot explain most of our SED, especially in the case of FSRQs and low energy peaked (LBL) BL Lacs. More complex models involving external Compton radiation or multiple SSC components are required to reproduce the overall SED and the observed spectral variability. While more than 50% of known radio bright high energy peaked (HBL) BL Lacs are detected in the LBAS sample, only less than 13% of known bright FSRQs and LBL BL Lacs are included. This suggests that the latter sources, as a class, may be much fainter gamma-ray emitters than LBAS blazars, and could in fact radiate close to the expectations of simple SSC models. We categorized all our sources according to a new physical classification scheme based on the generally accepted paradigm for Active Galactic Nuclei and on the results of this SED study. Since the LAT detector is more sensitive to flat spectrum gamma-ray sources, the correlation between nu(S)(peak) and gamma-ray spectral index strongly favors the detection of high energy peaked blazars, thus explaining the Fermi overabundance of this type of sources compared to radio and EGRET samples. This selection effect is similar to that experienced in the soft X-ray band where HBL BL Lacs are the dominant type of blazars.
Journal ArticleDOI
Probing the Inner Jet of the Quasar PKS 1510?089 with Multi-Waveband Monitoring During Strong Gamma-Ray Activity
Alan P. Marscher,Svetlana G. Jorstad,Svetlana G. Jorstad,Valeri M. Larionov,Valeri M. Larionov,Margo F. Aller,Hugh D. Aller,Anne Lähteenmäki,Ivan Agudo,Paul S. Smith,Mark Gurwell,Vladimir A. Hagen-Thorn,Vladimir A. Hagen-Thorn,Tatiana S. Konstantinova,Elena G. Larionova,L. V. Larionova,Daria A. Melnichuk,Dmitry A. Blinov,Evgenia N. Kopatskaya,Ivan S. Troitsky,Merja Tornikoski,Talvikki Hovatta,Gary D. Schmidt,Francesca D. D'Arcangelo,Francesca D. D'Arcangelo,Dipesh Bhattarai,Brian Taylor,Brian Taylor,Alice Olmstead,Emily Manne-Nicholas,Mar Roca-Sogorb,José L. Gómez,Ian M. McHardy,Omar M. Kurtanidze,Maria G. Nikolashvili,Givi N. Kimeridze,Lorand A. Sigua +36 more
TL;DR: In this article, the authors present results from monitoring the multi-waveband flux, linear polarization, and parsec-scale structure of the quasar PKS 1510-089, concentrating on eight major γ-ray flares that occurred during the interval 2009.5.
Journal ArticleDOI
Insights into the high-energy γ-ray emission of Markarian 501 from extensive multifrequency observations in the Fermi era
A. A. Abdo,A. A. Abdo,Markus Ackermann,Marco Ajello,Alice Allafort,Luca Baldini,Jean Ballet,Guido Barbiellini,Matthew G. Baring,Denis Bastieri,Keith Bechtol,R. Bellazzini,B. Berenji,Roger Blandford,Elliott D. Bloom,Emanuele Bonamente,A. W. Borgland,A. Bouvier,T. J. Brandt,J. Bregeon,A. Brez,M. Brigida,Pascal Bruel,R. Buehler,S. Buson,G. A. Caliandro,R. A. Cameron,A. Cannon,A. Cannon,P. Caraveo,S. Carrigan,J. M. Casandjian,E. Cavazzuti,Claudia Cecchi,Omer Celik,Omer Celik,E. Charles,A. Chekhtman,A. Chekhtman,C. C. Cheung,C. C. Cheung,James Chiang,Stefano Ciprini,R. Claus,Johann Cohen-Tanugi,Jan Conrad,S. Cutini,Charles D. Dermer,F. de Palma,E. Do Couto E Silva,Persis S. Drell,Richard Dubois,D. Dumora,C. Favuzzi,S. J. Fegan,Elizabeth C. Ferrara,W. B. Focke,P. Fortin,Marco Frailis,Lars Fuhrmann,Yasushi Fukazawa,Stefan Funk,P. Fusco,F. Gargano,D. Gasparrini,N. Gehrels,S. Germani,Nicola Giglietto,F. Giordano,Marcello Giroletti,T. Glanzman,G.L. Godfrey,I. A. Grenier,L. Guillemot,Sylvain Guiriec,M. Hayashida,E. Hays,D. Horan,R. E. Hughes,Gudlaugur Johannesson,A. S. Johnson,W. N. Johnson,Matthias Kadler,T. Kamae,Hideaki Katagiri,Jun Kataoka,Jürgen Knödlseder,M. Kuss,J. Lande,Luca Latronico,Sang Hun Lee,M. Lemoine-Goumard,Francesco Longo,F. Loparco,B. Lott,M. N. Lovellette,M. N. Lovellette,P. Lubrano,Grzegorz Madejski,A. Makeev,A. Makeev,Walter Max-Moerbeck,Mn Mazziotta,Julie McEnery,Julie McEnery,J. Mehault,Peter F. Michelson,W. Mitthumsiri,Tsunefumi Mizuno,A. A. Moiseev,A. A. Moiseev,C. Monte,M. E. Monzani,A. Morselli,Igor V. Moskalenko,S. Murgia,M. Naumann-Godo,Sho Nishino,P. L. Nolan,J. P. Norris,E. Nuss,T. Ohsugi,Atsushi Okumura,Nicola Omodei,E. Orlando,J. F. Ormes,David Paneque,David Paneque,J. H. Panetta,D. Parent,Vasiliki Pavlidou,T. J. Pearson,V. Pelassa,M. Pepe,Melissa Pesce-Rollins,F. Piron,T. A. Porter,S. Rainò,Riccardo Rando,M. Razzano,A. C. S. Readhead,A. Reimer,A. Reimer,Olaf Reimer,Olaf Reimer,Joseph L. Richards,Joachim Ripken,Steven Ritz,M. Roth,H. F.W. Sadrozinski,David Sánchez,A. Sander,Jeffrey D. Scargle,Carmelo Sgrò,E. J. Siskind,P. D. Smith,Gloria Spandre,P. Spinelli,Łukasz Stawarz,Mark Stevenson,M. S. Strickman,Kirill Sokolovsky,D. J. Suson,Hiromitsu Takahashi,Tadayuki Takahashi,Takaaki Tanaka,J. B. Thayer,J. G. Thayer,D. J. Thompson,L. Tibaldo,Diego F. Torres,G. Tosti,A. Tramacere,A. Tramacere,Yasunobu Uchiyama,T. L. Usher,Justin Vandenbroucke,V. Vasileiou,V. Vasileiou,N. Vilchez,V. Vitale,A. P. Waite,Paul J. Wang,Ann E. Wehrle,Brian L Winer,K. S. Wood,Zhenwei Yang,T. Ylinen,T. Ylinen,J. A. Zensus,M. Ziegler,Jelena Aleksić,L. A. Antonelli,P. Antoranz,Michael Backes,Juan Abel Barrio,J. Becerra González,J. Becerra González,W. Bednarek,Andrei Berdyugin,K. Berger,Elisa Bernardini,Adrian Biland,Oscar Blanch,R. K. Bock,A. Boller,G. Bonnoli,Pol Bordas,D. Borla Tridon,Valentí Bosch-Ramon,D. Bose,Ilana M. Braun,Thomas Bretz,M. Camara,E. Carmona,A. Carosi,Pierre Colin,E. Colombo,Jose Luis Contreras,Juan Cortina,Stefano Covino,Francesco Dazzi,A. De Angelis,E. De Cea del Pozo,B. De Lotto,M. De Maria,F. De Sabata,C. Delgado Mendez,A. Diago Ortega,A. Diago Ortega,M. Doert,Aaron Dominguez,D. Dominis Prester,Daniela Dorner,Michele Doro,Dominik Elsaesser,Daniel Ferenc,M. V. Fonseca,Ll. Font,R. J. García López,R. J. García López,M. Garczarczyk,Markus Gaug,Gianluca Giavitto,N. Godinovi,D. Hadasch,Artemio Herrero,Artemio Herrero,D. Hildebrand,D. Höhne-Mönch,J. Hose,Dario Hrupec,T. Jogler,S. Klepser,T. Krähenbühl,D. Kranich,J. Krause,A. La Barbera,E. Leonardo,Elina Lindfors,Saverio Lombardi,M. López,E. Lorenz,E. Lorenz,P. Majumdar,E. Makariev,G. Maneva,Nijil Mankuzhiyil,K. Mannheim,L. Maraschi,Mosè Mariotti,M. I. Martínez,Daniel Mazin,Mario Meucci,Jose Miguel Miranda,R. Mirzoyan,Hiroko Miyamoto,J. Moldón,Abelardo Moralejo,Daniel Nieto,K. Nilsson,Reiko Orito,I. Oya,Riccardo Paoletti,Josep M. Paredes,S. Partini,M. Pasanen,F. Pauss,R. Pegna,Miguel A. Pérez-Torres,Massimo Persic,J. Peruzzo,J. Pochon,P. G. Prada Moroni,Francisco Prada,Elisa Prandini,N. Puchades,Ivica Puljak,T. Reichardt,R. Reinthal,Wolfgang Rhode,Marc Ribó,J. Rico,M. Rissi,S. Rügamer,A. Saggion,K. Saito,Takashi Saito,M. Salvati,Miguel A. Sánchez-Conde,Miguel A. Sánchez-Conde,Konstancja Satalecka,V. Scalzotto,V. Scapin,C. Schultz,T. Schweizer,M. Shayduk,S. N. Shore,Agnieszka Sierpowska-Bartosik,A. Sillanpää,Julian Sitarek,Dorota Sobczyńska,Felix Spanier,S. Spiro,Antonio Stamerra,B. Steinke,J. Storz,N. Strah,J. C. Struebig,Tihomir Surić,L. O. Takalo,Fabrizio Tavecchio,Petar Temnikov,Tomislav Terzić,D. Tescaro,Masahiro Teshima,H. Vankov,Robert Wagner,Q. Weitzel,Victor Zabalza,Fabio Zandanel,R. Zanin,V. A. Acciari,T. C. Arlen,T. Aune,Wystan Benbow,D. Boltuch,S. M. Bradbury,J. H. Buckley,V. Bugaev,A. Cesarini,L. Ciupik,Wei Cui,R. Dickherber,Manel Errando,A. D. Falcone,J. P. Finley,G. Finnegan,Lucy Fortson,Amy Furniss,N. Galante,Daniel Gall,G. H. Gillanders,S. Godambe,J. Grube,R. Guenette,Geza Gyuk,D. S. Hanna,Jamie Holder,D. Huang,C. M. Hui,Thomas Brian Humensky,Philip Kaaret,N. Karlsson,M. Kertzman,David Kieda,A. Konopelko,Henric Krawczynski,F. Krennrich,M. J. Lang,Gernot Maier,S. McArthur,A. McCann,M. McCutcheon,P. Moriarty,Reshmi Mukherjee,R. A. Ong,A. N. Otte,D. Pandel,J. S. Perkins,A. Pichel,M. Pohl,John L. Quinn,K. Ragan,L. C. Reyes,P. T. Reynolds,E. Roache,H. J. Rose,A. C. Rovero,M. Schroedter,G. H. Sembroski,G. D. Şentürk,D. Steele,D. Steele,S. P. Swordy,G. Tešić,M. Theiling,S. Thibadeau,A. Varlotta,S. Vincent,S. P. Wakely,J. E. Ward,T. C. Weekes,Amanda Weinstein,T. Weisgarber,David A. Williams,Matthew Wood,B. Zitzer,M. Villata,C. M. Raiteri,Hugh D. Aller,M. F. Aller,A. A. Arkharov,Dmitry A. Blinov,P. Calcidese,Wen Ping Chen,N. V. Efimova,Givi N. Kimeridze,Tatiana S. Konstantinova,E. N. Kopatskaya,Ekaterina Koptelova,Omar M. Kurtanidze,Sofia O. Kurtanidze,Anne Lähteenmäki,Valeri M. Larionov,Valeri M. Larionov,Elena G. Larionova,L. V. Larionova,R. Ligustri,D. A. Morozova,M. G. Nikolashvili,Lorand A. Sigua,Ivan S. Troitsky,E. Angelakis,M. Capalbi,A. Carraminana,L. Carrasco,P. Cassaro,E. De la Fuente,Mark Gurwell,Yuri Y. Kovalev,Yu. A. Kovalev,Thomas P. Krichbaum,Hans A. Krimm,Hans A. Krimm,Paolo Leto,Matthew L. Lister,Giuseppe Maccaferri,Joseph Moody,Y. Mori,I. Nestoras,Andrea Orlati,C. Pagani,C. Pace,R. Pearson,M. Perri,B. G. Piner,Alexander B. Pushkarev,Eduardo Ros,Eduardo Ros,A. C. Sadun,T. Sakamoto,Merja Tornikoski,Y. Yatsu,A. C. Zook +474 more
TL;DR: In this paper, the gamma-ray activity of the blazar Mrk 501 during the first 480 days of Fermi operation was reported, and it was shown that the energy distribution of the freshly accelerated radiating electrons required to fit the time-averaged data has a broken power-law form in the energy range 0.3GeV-10TeV, with spectral indices 2.2 and 2.20.
Journal ArticleDOI
Flaring behavior of the quasar 3c 454.3 across the electromagnetic spectrum
Svetlana G. Jorstad,Svetlana G. Jorstad,Alan P. Marscher,Valeri M. Larionov,Valeri M. Larionov,Ivan Agudo,Paul S. Smith,Mark Gurwell,Anne Lähteenmäki,Merja Tornikoski,Alex Markowitz,A. A. Arkharov,Dmitry A. Blinov,Ritaban Chatterjee,Francesca D. D'Arcangelo,A. D. Falcone,José L. Gómez,Vladimir A. Hagen-Thorn,Vladimir A. Hagen-Thorn,B. Jordan,Givi N. Kimeridze,Tatiana S. Konstantinova,Evgenia N. Kopatskaya,Omar M. Kurtanidze,Elena G. Larionova,L. V. Larionova,Ian M. McHardy,Daria A. Melnichuk,Mar Roca-Sogorb,Gary D. Schmidt,Brian Skiff,Brian Taylor,Brian Taylor,Clemens Thum,Ivan S. Troitsky,Helmut Wiesemeyer +35 more
TL;DR: In this article, the behavior of the parsec-scale jet of the quasar 3C 454.3 during pronounced flaring in 2005-2008 was analyzed and correlations between optical variations and those at X-ray and γ-ray energies were found.
Journal ArticleDOI
The Structure and Emission Model of the Relativistic Jet in the Quasar 3C 279 Inferred from Radio to High-energy γ-Ray Observations in 2008-2010
M. Hayashida,M. Hayashida,G. M. Madejski,Krzysztof Nalewajko,M. Sikora,Ann E. Wehrle,Patrick Ogle,Werner Collmar,S. Larsson,Yasushi Fukazawa,Ryosuke Itoh,James Chiang,Łukasz Stawarz,Roger Blandford,Joseph L. Richards,Walter Max-Moerbeck,Anthony C. S. Readhead,R. Buehler,E. Cavazzuti,Stefano Ciprini,Stefano Ciprini,N. Gehrels,A. Reimer,Anna Szostek,Anna Szostek,Takaaki Tanaka,G. Tosti,G. Tosti,Yasunobu Uchiyama,Koji S. Kawabata,Masaru Kino,K. Sakimoto,Mahito Sasada,Susumu Sato,Makoto Uemura,Masayuki Yamanaka,Jochen Greiner,T. Kruehler,Andrea Rossi,Jean-Pierre Macquart,Douglas C.-J. Bock,M. Villata,C. M. Raiteri,Iván Agudo,Iván Agudo,Hugh D. Aller,M. F. Aller,Arkady A. Arkharov,Uwe Bach,Erika Benítez,Andrei Berdyugin,Dmitry A. Blinov,K. Blumenthal,Markus Böttcher,Carla Buemi,D. Carosati,Wen Ping Chen,A. Di Paola,Mauro Dolci,N. V. Efimova,N. V. Efimova,E. Forné,José L. Gómez,Mark Gurwell,Jochen Heidt,David Hiriart,B. Jordan,S. G. Jorstad,S. G. Jorstad,Manasvita Joshi,Givi N. Kimeridze,Tatiana S. Konstantinova,E. N. Kopatskaya,Ekaterina Koptelova,Ekaterina Koptelova,Omar M. Kurtanidze,Anne Lähteenmäki,A. Lamerato,Valeri M. Larionov,Valeri M. Larionov,Valeri M. Larionov,Elena G. Larionova,L. V. Larionova,Paolo Leto,Elina Lindfors,Alan P. Marscher,I. M. McHardy,Sol N. Molina,D. A. Morozova,M. G. Nikolashvili,Kari Nilsson,R. Reinthal,P. Roustazadeh,T. Sakamoto,Lorand A. Sigua,A. Sillanpää,L. O. Takalo,Joni Tammi,Brian W. Taylor,Brian W. Taylor,Merja Tornikoski,Corrado Trigilio,Ivan S. Troitsky,G. Umana +103 more
TL;DR: In this paper, the authors present time-resolved broadband observations of the quasar 3C 279 obtained from multi-wavelength campaigns conducted during the first two years of the Fermi Gamma-ray Space Telescope mission.