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Rapid Variability of Blazar 3C 279 During Flaring States in 2013-2014 with Joint Fermi-LAT, NuSTAR, Swift, and Ground-Based Multi-Wavelength Observations

Hayashida, M. and Nalewajko, K. and Madejski, G. M. and Sikora, M. and Itoh, R. and Ajello, M. and Blandford, R. D. and Buson, S. and Chiang, J. and Fukazawa, Yasushi and Furniss, A. K. and Urry, C. M. and Hasan, I. and Harrison, F. A. and Alexander, D. M. and Baloković, M. and Barret, D. and Christensen, F. E. and Boggs, S. E. and Craig, W. W. and Forster, K. and Giommi, P. and Grefenstette, B. W. and Hailey, C. and Hornstrup, A. and Kitaguchi, T. and Koglin, J. E. and Madsen, K. K. and Mao, P. H. and Miyasaka, H. and Mori, K. and Perri, M. and Pivovaroff, M. J. and Puccetti, S. and Rana, V. and Stern, D. and Tagliaferri, G. and Westergaard, N. J. and Zhang, W. W. and Zoglauer, A. and Gurwell, M. A. and Uemura, M. and Akitaya, H. and Kawabata, K. S. and Kawaguchi, K. and Kanda, Y. and Moritani, Y. and Takaki, K. and Ui, T. and Yoshida, M. and Agarwal, A. and Gupta, A. C. (2015) Rapid Variability of Blazar 3C 279 During Flaring States in 2013-2014 with Joint Fermi-LAT, NuSTAR, Swift, and Ground-Based Multi-Wavelength Observations. Astrophysical Journal, 807 (1). Art. No. 79. ISSN 0004-637X.

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We report the results of a multiband observing campaign on the famous blazar 3C 279 conducted during a phase of increased activity from 2013 December to 2014 April, including first observations of it with NuSTAR. The gamma-ray emission of the source measured by Fermi-LAT showed multiple distinct flares reaching the highest flux level measured in this object since the beginning of the Fermi mission, with F(E > 100 MeV) of 10^(-5) photons cm^(-2) s^(-1), and with a flux-doubling time scale as short as 2 hr. The gamma-ray spectrum during one of the flares was very hard, with an index of Gamma(gamma) = 1.7 +/- 0.1, which is rarely seen in flat-spectrum radio quasars. The lack of concurrent optical variability implies a very high Compton dominance parameter L-gamma/L-syn > 300. Two 1 day NuSTAR observations with accompanying Swift pointings were separated by 2 weeks, probing different levels of source activity. While the 0.5 - 70 keV X-ray spectrum obtained during the first pointing, and fitted jointly with Swift-XRT is well-described by a simple power law, the second joint observation showed an unusual spectral structure: the spectrum softens by Delta Gamma(X) similar or equal to 0.4 at similar to 4 keV. Modeling the broadband spectral energy distribution during this flare with the standard synchrotron plus inverse-Compton model requires: (1) the location of the gamma-ray emitting region is comparable with the broad-line region radius, (2) a very hard electron energy distribution index p similar or equal to 1, (3) total jet power significantly exceeding the accretion-disk luminosity L-j/L-d greater than or similar to 10, and (4) extremely low jet magnetization with L-B/L-j less than or similar to 10^(-4). We also find that single-zone models that match the observed gamma-ray and optical spectra cannot satisfactorily explain the production of X-ray emission.

Item Type:Article
Related URLs:
URLURL TypeDescription
Blandford, R. D.0000-0002-1854-5506
Urry, C. M.0000-0002-0745-9792
Harrison, F. A.0000-0003-2992-8024
Alexander, D. M.0000-0002-5896-6313
Boggs, S. E.0000-0001-9567-4224
Madsen, K. K.0000-0003-1252-4891
Mori, K.0000-0002-9709-5389
Puccetti, S.0000-0002-2734-7835
Rana, V.0000-0003-1703-8796
Stern, D.0000-0003-2686-9241
Additional Information:© 2015 IOP Publishing. Received 2015 February 14; Accepted 2015 March 31; Published 2015 July 2. The Fermi-LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States; the Commissariat à l'Energie Atomique and the Centre National de la Recherche Scientifique/Institut National de Physique Nucléaire et de Physique des Particules in France; the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy; the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan; and the K. A. Wallenberg Foundation, the Swedish Research Council, and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d'Études Spatiales in France. This work was partially supported under the NASA contract no. NNG08FD60C, and made use of observations from the NuSTAR mission, a project led by California Institute of Technology, managed by the Jet Propulsion Laboratory, and funded by NASA. We thank the NuSTAR Operations, Software, and Calibration teams for support of the execution and analysis of these observations. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Science Data Center (ASDC, Italy) and the California Institute of Technology (USA). This research has made use of the XRT Data Analysis Software (XRTDAS) developed under the responsibility of the ASI Science Data Center (ASDC), Italy. The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. K.N. was supported by NASA through Einstein Postdoctoral Fellowship grant number PF3–140130 awarded by the Chandra X-ray Center, which is operated by the Smithsonian Astrophysical Observatory for NASA under contract NAS8–03060. M.B. acknowledges support from NASA Headquarters under the NASA earth and Space Science Fellowship Program, grant NNX14AQ07H. Facilities: Fermi (LAT) - Fermi Gamma-Ray Space Telescope (formerly GLAST), NuSTAR - The NuSTAR (Nuclear Spectroscopic Telescope Array) mission, Swift - Swift Gamma-Ray Burst Mission, CTIO: 0.9m - , CTIO: 1.0m - , CTIO: 1.3m - , CTIO: 1.5m - , SMA - SubMillimeter Array
Group:NuSTAR, Space Radiation Laboratory
Funding AgencyGrant Number
Department of Energy (DOE)UNSPECIFIED
Commissariat à l’Energie Atomique (CEA)UNSPECIFIED
Agenzia Spaziale Italiana (ASI)UNSPECIFIED
Ministry of Education, Culture, Sports, Science and Technology (MEXT)UNSPECIFIED
High Energy Accelerator Research Organization (KEK) UNSPECIFIED
K. A. Wallenberg Foundation UNSPECIFIED
Swedish Research CouncilUNSPECIFIED
Swedish National Space Board (SNSB) UNSPECIFIED
NASA Einstein FellowshipPF3–140130
NASA Earth and Space Science FellowshipNNX14AQ07H
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Institut National de Physique Nucléaire et de Physique des Particules (IN2P3)UNSPECIFIED
Istituto Nazionale di Fisica Nucleare (INFN)UNSPECIFIED
Japan Aerospace Exploration Agency (JAXA) UNSPECIFIED
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2015-54
Record Number:CaltechAUTHORS:20150907-142839153
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:60084
Deposited By: Joy Painter
Deposited On:11 Sep 2015 14:51
Last Modified:31 Oct 2017 21:29

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