Variability in the Blazar 3C 454.3

摘要

The blazar 3C 454.3 was revealed by Fermi Space Telescope to be in an exceptionally high flux state in July 2008. We performed a multi-wavelength monitoring campaign from August to December 2008 and 2009 on this blazar using IR and optical observations from the SMARTS telescopes to-gether with publicly available data from Swift and daily gamma-ray fluxes from Fermi. We find an excellent, correlation between the infrared (IR), optical, ul-traviolet (UV) and gamma-ray light curves, with a time lag of less than one day. The amplitude of the infrared variability is larger than at optical or UV wave-lengths, and the optical and IR emission shows redder colors at higher flux levels, consistent with an underlying themal accretion disk. The variability character-istics of 3C 454.3 suggest an external Compton model in which electrons with Lorentz factor Υ～10~(3-4) produce synchrotron emission peaking in the IR while inverse Compton scattering disk or line photons to GeV energies.