A Study of the Long-Term Spectral Variations of 3C 66A Observed with the Fermi and Kanata Telescopes

作者：Itoh Ryosuke^*; Fukazawa Yasushi; Chiang James; Hanabata Yoshitaka; Hayashida Masaaki; Hayashi Katsuhiro; Mizuno Tsunefumi; Ohno Masanori; Ohsugi Takashi; Perkins Jeremy S; Raino Silvia; Reyes Luis C; Takahashi Hiromitsu; Tanaka Yasuyuki; Tosti Gino; Akitaya Hiroshi; Arai Akira; Kino Masaru; Ikejiri Yuki; Kawabata Koji S; Komatsu Tomoyuki; Sakimoto Kiyoshi; Sasada Mahito; Sato Shuji; Uemura Makoto; Ui Takahiro; Yamanaka Masayuki; Yoshida Michitoshi

来源：Publications of the Astronomical Society of Japan, 2013, 65(1): UNSP 18.

DOI：10.1093/pasj/65.1.18

• galaxies: BL Lacertae objects: general
• gamma rays: observations

3C 66A is an intermediate-frequency-peaked BL Lac object detected by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. We present a study of the long-term variations of this blazar seen over similar to 2 yr at GeV energies with Fermi and in the optical (flux and polarization) and near infrared with the Kanata telescope. In 2008, the first year of the study, we find a correlation between the gamma-ray flux and the measurements taken with the Kanata telescope. This is in contrast to the later measurements performed during 2009-2010 which show only a weak correlation along with a gradual increase of the optical flux. We calculate an external seed photon energy density assuming that the gamma-ray emission is due to external Compton scattering. The energy density of the external photons is found to be higher by a factor of two in 2008 compared to 2009-2010. We conclude that the different behaviors observed between the first year and the later years might be explained by postulating two different emission components.

• 出版日期2013-2-25