Journal article
(Original article)

Publication Details

Author(s): Uchiyama Y, Sikora M, Nalewajko K, Ohsugi T, Maldera S, Negro M, La Mura G, Mirabal N, Anantua R, Yuan Y, Cavazzuti E, Bonino R, Moskalenko IV, Stawarz L, Orlando E, Porter TA, Reimer A, Lott B, Simone D, Buehler R, Caragiulo M, Caraveo PA, Spada F, Cecchi C, Cheung CC, Costanza F, Drell PS, Di Venere L, Monzani ME, D'Ammando F, Michelson PF, Spinelli P, Gonzalez JB, Bissaldi E, Fusco P, Funk S, Ferrara EC, Chiaro G, Fukazawa Y, Asano K, Johannesson G, Ackermann M, Guillemot L, Caliandro GA, Cameron RA, Chiang J, Principe G, Grenier IA, Bruel P, Larsson S, Bloom ED, Pesce-Rollins M, Gargano F, Madejski GM, Di Mauro M, Digel SW, Di Lalla N, Hayashida M, Hays E, Pivato G, Zimmer S, Giroletti M, Magill JD, Desiante R, De Palma F, Favuzzi C, Troja E, Torres DF, Kensei S, Scargle JD, Thompson DJ, Li J, Morselli A, Paneque D, Guiriec S, Cutini S, Perkins JS, Nuss E, Razzano M, Razzaque S, Siskind EJ, Sgro C, Fegan SJ, Cohen-Tanugi J, Horan D, Thayer JB, Bellazzini R, Bastieri D, Barbiellini G, Mizuno T, Mazziotta MN, Mayer M, Gasparrini D, Kocevski D, Kuss M, Ciprini S, Blandford RD, Rando R, Piron F, Lubrano P, Baldini L, Longo F, Latronico L, Lovellette MN, Manfreda A, Bottacini E, Giglietto N, Loparco F, Giordano F
Journal: Astrophysical Journal Letters
Publisher: American Astronomical Society
Publication year: 2016
Volume: 824
Journal issue: 2
ISSN: 2041-8205


On 2015 June 16, Fermi- LAT observed a giant outburst from the flat spectrum radio quasar 3C 279 with a peak >100 MeV flux of similar to 3.6 x 10(-5) photons cm(-2) s(-1), averaged over orbital period intervals. It is historically the highest gamma-ray flux observed from the source, including past EGRET observations, with the gamma-ray isotropic luminosity reaching similar to 10(49) erg s(-1). During the outburst, the Fermi spacecraft, which has an orbital period of 95.4 minutes, was operated in a special pointing mode to optimize the exposure for 3C 279. For the first time, significant flux variability at sub-orbital timescales was found in blazar observations by Fermi- LAT. The source flux variability was resolved down to 2-minute binned timescales, with flux doubling times of less than 5 minutes. The observed minute-scale variability suggests a very compact emission region at hundreds of Schwarzschild radii from the central engine in conical jet models. A minimum bulk jet Lorentz factor (Gamma) of 35 is necessary to avoid both internal gamma-ray absorption and super-Eddington jet power. In the standard external radiation Comptonization scenario, G should be at least 50 to avoid overproducing the synchrotron self-Compton component. However, this predicts extremely low magnetization (similar to 5 x 10(-4)). Equipartition requires Gamma as high as 120, unless the emitting region is a small fraction of the dissipation region. Alternatively, we consider. rays originating as synchrotron radiation of gamma e similar to 1.6 x 10(6) electrons, in a magnetic field B similar to 1.3 kG, accelerated by strong electric fields E similar to B in the process of magnetoluminescence. At such short distance scales, one cannot immediately exclude the production of gamma-rays in hadronic processes.

FAU Authors / FAU Editors

Funk, Stefan Prof. Dr.
Lehrstuhl für Physik
Principe, Giacomo
Lehrstuhl für Physik

External institutions
AlbaNova University Centre / Kungliga Tekniska Högskolan AlbaNova Universitetscentrum
Deutsches Elektronen-Synchrotron DESY
École Polytechnique - Université Paris-Saclay
Hiroshima University
Italian Space Agency / Agenzia Spaziale Italiana (ASI)
Jagiellonian University / Uniwersytet Jagielloński (UJ)
National Aeronautics and Space Administration (NASA)
National Institute for Astrophysics / Istituto Nazionale Astrofisica (INAF)
National Institute for Nuclear Physics / Istituto Nazionale di Fisica Nucleare (INFN)
Nicolaus Copernicus Astronomical Centre of the Polish Academy of Sciences
NYCB Real-Time Computing, Inc.
Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC)
Stanford University
Université Bordeaux 1, Sciences et Technologies
University of Bari Aldo Moro / Università degli Studi di Bari Aldo Moro
University of Geneva / Université de Genève (UNIGE)
University of Iceland (UI)
University of Johannesburg
University of Maryland
University of Montpellier / Université Montpellier
University of Orléans / Université d'Orléans
University of Padua
University of Paris 7 - Denis Diderot / Université Paris VII Denis Diderot
University of Tokyo
U.S. Naval Research Laboratory

How to cite

Uchiyama, Y., Sikora, M., Nalewajko, K., Ohsugi, T., Maldera, S., Negro, M.,... Giordano, F. (2016). MINUTE-TIMESCALE > 100 MeV gamma-RAY VARIABILITY DURING THE GIANT OUTBURST OF QUASAR 3C 279 OBSERVED BY FERMI-LAT IN 2015 JUNE. Astrophysical Journal Letters, 824(2). https://dx.doi.org/10.3847/2041-8205/824/2/L20

Uchiyama, Y., et al. "MINUTE-TIMESCALE > 100 MeV gamma-RAY VARIABILITY DURING THE GIANT OUTBURST OF QUASAR 3C 279 OBSERVED BY FERMI-LAT IN 2015 JUNE." Astrophysical Journal Letters 824.2 (2016).


Last updated on 2018-15-11 at 13:50