J
Jochen Heidt
Researcher at Heidelberg University
Publications - 196
Citations - 9004
Jochen Heidt is an academic researcher from Heidelberg University. The author has contributed to research in topics: BL Lac object & Blazar. The author has an hindex of 55, co-authored 193 publications receiving 8566 citations. Previous affiliations of Jochen Heidt include European Southern Observatory & Max Planck Society.
Papers
More filters
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
A massive binary black-hole system in OJ 287 and a test of general relativity
Mauri Valtonen,Harry Lehto,Kari Nilsson,Jochen Heidt,L. O. Takalo,A. Sillanpää,Carolin Villforth,M. R. Kidger,G. Poyner,T. Pursimo,Staszek Zola,Staszek Zola,Jin Wu,Xingjiang Zhou,Kozo Sadakane,Marek Drozdz,Dorota Kozieł,Dragomir Marchev,Waldemar Ogloza,C. Porowski,Michal Siwak,G. Stachowski,M. Winiarski,V.-P. Hentunen,M. Nissinen,Alexios Liakos,S.S. Doğru +26 more
TL;DR: The observations confirm the binary nature of the system and also provide evidence for the loss of orbital energy in agreement (within 10 per cent) with the emission of gravitational waves from the system.
Journal ArticleDOI
Rapid variability in S5 0716+714 across the electromagnetic spectrum
Stefan Wagner,A. Witzel,Jochen Heidt,Thomas P. Krichbaum,S. J. Qian,A. Quirrenbach,R. Wegner,Hugh D. Aller,Margo F. Aller,K. Anton,Immo Appenzeller,Andreas Eckart,Alexander Kraus,C. E. Naundorf,R. Kneer,Wolfgang Steffen,J. A. Zensus +16 more
Journal ArticleDOI
Location of γ-ray Flare Emission in the Jet of the BL Lacertae Object OJ287 More than 14 pc from the Central Engine
Iván Agudo,Svetlana G. Jorstad,Svetlana G. Jorstad,Alan P. Marscher,Valeri M. Larionov,Valeri M. Larionov,José L. Gómez,Anne Lähteenmäki,Mark Gurwell,Paul S. Smith,Helmut Wiesemeyer,Clemens Thum,Jochen Heidt,D. Blinov,D. Blinov,Francesca D. D’Arcangelo,Francesca D. D’Arcangelo,Vladimir A. Hagen-Thorn,Vladimir A. Hagen-Thorn,D. A. Morozova,E. Nieppola,E. Nieppola,Mar Roca-Sogorb,Gary D. Schmidt,Brian W. Taylor,Brian W. Taylor,Merja Tornikoski,Ivan S. Troitsky +27 more
TL;DR: In this article, the authors combine time-dependent multi-waveband flux and linear polarization observations with submilliarcsecond-scale polarimetric images at the BL Lacertae type blazar OJ287 to locate the?-ray emission in prominent flares in the jet of the source > 14?pc from the central engine.
Journal ArticleDOI
Location of gamma-ray Flare Emission in the Jet of the BL Lacertae Object OJ287 more than 14pc from the Central Engine
Ivan Agudo,Svetlana G. Jorstad,Alan P. Marscher,Valeri M. Larionov,José L. Gómez,Anne Lähteenmäki,Mark Gurwell,Paul S. Smith,Helmut Wiesemeyer,Clemens Thum,Jochen Heidt,D. Blinov,Francesca D. D'Arcangelo,Vladimir A. Hagen-Thorn,D. A. Morozova,E. Nieppola,Mar Roca-Sogorb,Gary D. Schmidt,Brian W. Taylor,Merja Tornikoski,Ivan S. Troitsky +20 more
TL;DR: In this paper, the gamma-ray and mm-wave flux and linear polarization observations were combined with sub-milliarcsecond-scale polarimetric images at lambda=7mm of the BL Lacertae-type blazar OJ287 to locate the gamma ray emission in prominent flares in the jet of the source > 14pc from the central engine.