Bibcode
Seta, Hiromi; Isobe, Naoki; Tashiro, Makoto S.; Yaji, Yuichi; Arai, Akira; Fukuhara, Masayuki; Kohno, Kotaro; Nakanishi, Kouichiro; Sasada, Mahito; Shimajiri, Yoshito; Tosaki, Tomoka; Uemura, Makoto; Anderhub, Hans; Antonelli, Lucio Angelo; Antoranz, Pedro; Backes, Michael; Baixeras, Carmen; Balestra, Silvia; Barrio, Juan Abel; Bastieri, Denis; Becerra González, Josefa; Becker, Julia K.; Bednarek, Wodzimierz; Berger, Karsten; Bernardini, Elisa; Biland, Adrian; Bock, Rudolf K.; Bonnoli, Giacomo; Bordas, Pol; Borla Tridon, Daniela; Bosch-Ramon, Valenti; Bose, Debanjan; Braun, Isabel; Bretz, Thomas; Britvitch, Ilia; Camara, Miguel; Carmona, Emiliano; Commichau, Sebastian; Contreras, José Luis; Cortina, Juan; Costado Dios, Ma Teresa; Covino, Stefano; Curtef, Valentin; Dazzi, Francesco; de Angelis, Alessandro; de Cea Del Pozo, Elsa; de Los Reyes, Raquel; de Lotto, Barbara; de Maria, Michela; de Sabata, Francesco; Delgado Méndez, Carlos; Domínguez, Alberto; Dorner, Daniela; Doro, Michele; Elsaesser, Dominik; Errando, Manel; Ferenc, Daniela; Fernández, Enrique; Firpo, Roger; Fonseca, Maria Victoria; Font, Lluis; Galante, Nicola; García López, Ramon J.; Garczarczyk, Markus; Gaug, Markus; Goebel, Florian; Hadasch, Daniela; Hayashida, Masaaki; Herrero, Artemio; Hildebrand, Dorothée; Höhne-Mönch, Daniel; Hose, Jürgen; Hsu, Ching Cheng; Jogler, Tobias; Kranich, Daniel; La Barbera, Antonio; Laille, Alvin; Leonardo, Elvira; Lindfors, Elina; Lombardi, Saverio; Longo, Francesco; López, Donatella; Lorenz, Eckart; Majumdar, Pratik; Maneva, Galina; Mankuzhiyil, Nijil; Mannheim, Karl; Maraschi, Laura; Mariotti, Mosé; Martínez, Manel; Mazin, Daniel; Meucci, Mario; Meyer, Markus; Miguel Miranda, Jose; Mirzoyan, Razmick; Miyamoto, Hiroko; Moldón, Javier; Moles, Mariano; Moralejo, Abelardo; Nieto, Daniel et al.
Bibliographical reference
Publications of the Astronomical Society of Japan, Vol.61, No.5, pp.1011--1022
Advertised on:
10
2009
Citations
33
Refereed citations
24
Description
Suzaku observations of the blazar OJ 287 were performed in 2007 April
10-13 and November 7-9. They correspond to a quiescent and a flaring
state, respectively. The X-ray spectra of the source can be
well-described with single power-law models in both exposures. The
derived X-ray photon index and the flux density at 1 keV were found to
be Γ = 1.65±0.02 and S1keV = 215±5 nJy in
the quiescent state. In the flaring state, the source exhibited a harder
X-ray spectrum (Γ = 1.50±0.01) with a nearly doubled X-ray
flux density of S1keV = 404+6-5nJy.
Moreover, significant hard X-ray signals were detected up to ˜27
keV. In cooperation with Suzaku, simultaneous radio, optical, and
very-high-energy γ-ray observations of OJ 287 were performed with
the Nobeyama Millimeter Array, the KANATA telescope, and the MAGIC
telescope, respectively. The radio and optical fluxes in the flaring
state (3.04±0.46 Jy and 8.93±0.05 mJy at 86.75 Hz and in
the V-band, respectively) were found to be higher by a factor of 2-3
than those in the quiescent state (1.73±0.26 Jy and
3.03±0.01 mJy at 86.75 Hz and in the V-band, respectively). No
notable γ-ray events were detected in either observation. The
spectral energy distribution of OJ 287 indicated that the X-ray spectrum
was dominated by inverse Compton radiation in both observations, while
synchrotron radiation exhibited a spectral cutoff at around the optical
frequency. Furthermore, no significant difference in the synchrotron
cutoff frequency was found between the quiescent and flaring states.
According to a simple synchrotron self-Compton model, the change of the
spectral energy distribution is due to an increase in the energy density
of electrons with small changes of both the magnetic field strength and
the maximum Lorentz factor of electrons.
Related projects
Particle Astrophysics
The MAGIC Collaboration is integrated by 20 research institutes and university departments from Armenia, Bulgaria, Finland, Germany, Italy, Poland, Spain, Switzerland and USA. The collaboration comprises two 17m diameter telescopes, located at the Roque de los Muchachos Observatory, designed to measure the Cherenkov radiation associated with
Ramón
García López