MULTIWAVELENGTH OBSERVATIONS OF 3C 454.3. II. THE AGILE 2007 DECEMBER CAMPAIGN

Journal Article · Sun Dec 20 04:00:00 EST 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/707/2/1115· OSTI ID:21392580

Donnarumma, I; Pucella, G; Vittorini, V; D'Ammando, F; Tavani, M ^[1]; Vercellone, S ^[2]; Raiteri, C M; Villata, M; Smart, R L ^[3]; Perri, M ^[4]; Chen, W P ^[5]; Kataoka, J; Kawai, N; Mori, Y ^[6]; Tosti, G; Impiombato, D ^[7]; Takahashi, T; Sato, R ^[8]; Bulgarelli, A ^[9]

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1. INAF/IASF-Rome, Via del Fosso del Cavaliere 100, I-00133 Rome (Italy)
2. INAF/IASF Palermo Via Ugo La Malfa 153, 90146 Palermo (Italy)
3. INAF/OATo, Via Osservatorio 20, I-10025 Pino Torinese (Italy)
4. ASI-ASDC, Via G. Galilei, I-00044 Frascati (Rome) (Italy)
5. Institute of Astronomy, National Central University, Taiwan (China)
6. Department of Physics, Tokyo Institute of Technology, Tokyo (Japan)
7. Dip. di Fisica, Univ. di Perugia, Via Pascoli, I-06123 Perugia (Italy)
8. ISAS/JAXA, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan)
9. INAF/IASF-Bologna, Via Gobetti 101, I-40129 Bologna (Italy)

We report on the second Astrorivelatore Gamma a Immagini Leggero (AGILE) multiwavelength campaign of the blazar 3C 454.3 during the first half of 2007 December. This campaign involved AGILE, Spitzer, Swift, Suzaku, the Whole Earth Blazar Telescope (WEBT) consortium, the Rapid Eye Mount (REM), and the Multicolor Imaging Telescopes for Survey and Monstrous Explosions (MITSuME) telescopes, offering a broadband coverage that allowed for a simultaneous sampling of the synchrotron and inverse Compton (IC) emissions. The two-week AGILE monitoring was accompanied by radio to optical monitoring by WEBT and REM, and by sparse observations in mid-infrared and soft/hard X-ray energy bands performed by means of Target of Opportunity observations by Spitzer, Swift, and Suzaku, respectively. The source was detected with an average flux of approx250 x 10{sup -8} photons cm{sup -2} s{sup -1} above 100 MeV, typical of its flaring states. The simultaneous optical and gamma-ray monitoring allowed us to study the time lag associated with the variability in the two energy bands, resulting in a possible approx<one-day delay of the gamma-ray emission with respect to the optical one. From the simultaneous optical and gamma-ray fast flare detected on December 12, we can constrain the delay between the gamma-ray and optical emissions within 12 hr. Moreover, we obtain three spectral energy distributions (SEDs) with simultaneous data for 2007 December 5, 13, and 15, characterized by the widest multifrequency coverage. We found that a model with an external Compton on seed photons by a standard disk and reprocessed by the broad-line regions does not describe in a satisfactory way the SEDs of 2007 December 5, 13, and 15. An additional contribution, possibly from the hot corona with T = 10{sup 6} K surrounding the jet, is required to account simultaneously for the softness of the synchrotron and the hardness of the IC emissions during those epochs.

• OSTI ID: 21392580
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 707; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BOSONS
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
EMISSION
ENERGY RANGE
ENERGY SPECTRA
EXPLOSIONS
FLARING
GALAXIES
GAMMA RADIATION
HARD X RADIATION
IONIZING RADIATIONS
MASSLESS PARTICLES
MEV RANGE
MEV RANGE 100-1000
PHOTONS
QUASARS
RADIATIONS
SPECTRA
TELESCOPES
X RADIATION