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

Itoh, Ryosuke; Fukazawa, Yasushi; Chiang, James; Hanabata, Yoshitaka; Hayashida, Masaaki; Hayashi, Katsuhiro; Mizuno, Tsunefumi; Ohno, Masanori; Ohsugi, Takashi; Perkins, Jeremy S.; Rainò, Silvia; Reyes, Luis C.; Takahashi, Hiromitsu; Tanaka, Yasuyuki; Tosti, Gino; Akitaya, Hiroshiv; 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

doi:10.1093/pasj/65.1.18

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

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Abstract

3C 66A is an intermediate-frequency-peaked BL Lac object detected by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. Here, we present a study of the long-term variations of this blazar seen over ~ 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. Finally, we conclude that the different behaviors observed between the first year and the later years might be explained by postulating two different emission components.

Publication Date:: Mon Feb 25 00:00:00 EST 2013

Research Org.:: SLAC National Accelerator Lab., Menlo Park, CA (United States)

Sponsoring Org.:: USDOE

Contributing Org.:: Fermi-LAT Collaboration

OSTI Identifier:: 1356601

Grant/Contract Number:: AC02-76SF00515

Resource Type:: Accepted Manuscript

Journal Name:: Publications of the Astronomical Society of Japan

Additional Journal Information:: Journal Volume: 65; Journal Issue: 1; Journal ID: ISSN 0004-6264

Country of Publication:: United States

Language:: English

Subject:: 79 ASTRONOMY AND ASTROPHYSICS; galaxies: BL Lacertae objects: general; gamma rays: general

Citation Formats


                    Itoh, Ryosuke, Fukazawa, Yasushi, Chiang, James, Hanabata, Yoshitaka, Hayashida, Masaaki, Hayashi, Katsuhiro, Mizuno, Tsunefumi, Ohno, Masanori, Ohsugi, Takashi, Perkins, Jeremy S., Rainò, Silvia, Reyes, Luis C., Takahashi, Hiromitsu, Tanaka, Yasuyuki, Tosti, Gino, Akitaya, Hiroshiv, Arai, Akira, Kino, Masaru, Ikejiri, Yuki, Kawabata, Koji S., Komatsu, Tomoyuki, Sakimoto, Kiyoshi, Sasada, Mahito, Sato, Shuji, Uemura, Makoto, Ui, Takahiro, Yamanaka, Masayuki, and Yoshida, Michitoshi. A Study of the Long-Term Spectral Variations of 3C 66A Observed with the Fermi and Kanata Telescopes.  United States: N. p., 2013. 
Web.  doi:10.1093/pasj/65.1.18.

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                    Itoh, Ryosuke, Fukazawa, Yasushi, Chiang, James, Hanabata, Yoshitaka, Hayashida, Masaaki, Hayashi, Katsuhiro, Mizuno, Tsunefumi, Ohno, Masanori, Ohsugi, Takashi, Perkins, Jeremy S., Rainò, Silvia, Reyes, Luis C., Takahashi, Hiromitsu, Tanaka, Yasuyuki, Tosti, Gino, Akitaya, Hiroshiv, 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. A Study of the Long-Term Spectral Variations of 3C 66A Observed with the Fermi and Kanata Telescopes.  United States.  https://doi.org/10.1093/pasj/65.1.18

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                    Itoh, Ryosuke, Fukazawa, Yasushi, Chiang, James, Hanabata, Yoshitaka, Hayashida, Masaaki, Hayashi, Katsuhiro, Mizuno, Tsunefumi, Ohno, Masanori, Ohsugi, Takashi, Perkins, Jeremy S., Rainò, Silvia, Reyes, Luis C., Takahashi, Hiromitsu, Tanaka, Yasuyuki, Tosti, Gino, Akitaya, Hiroshiv, Arai, Akira, Kino, Masaru, Ikejiri, Yuki, Kawabata, Koji S., Komatsu, Tomoyuki, Sakimoto, Kiyoshi, Sasada, Mahito, Sato, Shuji, Uemura, Makoto, Ui, Takahiro, Yamanaka, Masayuki, and Yoshida, Michitoshi. Mon .  
"A Study of the Long-Term Spectral Variations of 3C 66A Observed with the Fermi and Kanata Telescopes".  United States.  https://doi.org/10.1093/pasj/65.1.18.  https://www.osti.gov/servlets/purl/1356601.

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@article{osti_1356601,

  title        = {A Study of the Long-Term Spectral Variations of 3C 66A Observed with the Fermi and Kanata Telescopes},

  author       = {Itoh, Ryosuke and Fukazawa, Yasushi and Chiang, James and Hanabata, Yoshitaka and Hayashida, Masaaki and Hayashi, Katsuhiro and Mizuno, Tsunefumi and Ohno, Masanori and Ohsugi, Takashi and Perkins, Jeremy S. and Rainò, Silvia and Reyes, Luis C. and Takahashi, Hiromitsu and Tanaka, Yasuyuki and Tosti, Gino and Akitaya, Hiroshiv and Arai, Akira and Kino, Masaru and Ikejiri, Yuki and Kawabata, Koji S. and Komatsu, Tomoyuki and Sakimoto, Kiyoshi and Sasada, Mahito and Sato, Shuji and Uemura, Makoto and Ui, Takahiro and Yamanaka, Masayuki and Yoshida, Michitoshi},

  abstractNote = {3C 66A is an intermediate-frequency-peaked BL Lac object detected by the Large Area Telescope onboard the Fermi Gamma-ray Space Telescope. Here, we present a study of the long-term variations of this blazar seen over ~ 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. Finally, we conclude that the different behaviors observed between the first year and the later years might be explained by postulating two different emission components.},

  doi          = {10.1093/pasj/65.1.18},

  journal      = {Publications of the Astronomical Society of Japan},

  number       = 1,

  volume       = 65,

  place        = {United States},

  year         = {Mon Feb 25 00:00:00 EST 2013},

  month        = {Mon Feb 25 00:00:00 EST 2013}

}

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