SMARTS OPTICAL AND INFRARED MONITORING OF 12 GAMMA-RAY BRIGHT BLAZARS
Urry, C. Megan
We present multiwavelength data for 12 blazars observed from 2008 to 2010 as part of an ongoing optical–infrared photometric monitoring project. Sources were selected to be bright, southern (δ < 20◦) blazars observed by the Fermi Gamma-Ray Space Telescope. Light curves are presented for the 12 blazars in BVRJK at near-daily cadence. We find that optical and infrared fluxes are well correlated in all sources. Gamma-ray bright flat spectrum radio quasars (FSRQs) in our sample have optical/infrared emission correlated with gamma-rays consistent with inverse Compton-scattering models. In FSRQs, variability amplitude increases toward IR wavelengths, consistent with the presence of a thermal accretion disk varying on significantly longer timescales than the jet. In BL Lac objects, variability is mainly constant, or increases toward shorter wavelength. FSRQs have redder optical–infrared colors when they are brighter,whileBLLac objects showno such trend. Several objects showcomplicated color–magnitude behavior: AO 0235+164 appears in two different states depending on its gamma-ray intensity. OJ 287 and 3C 279 show some hysteresis tracks in their color–magnitude diagrams. Individual flares may be achromatic or otherwise depart from the trend, suggesting different jet components becoming important at different times. We present a time-dependent spectral energy distribution of the bright FSRQ 3C 454.3 during its 2009 December flare, which is well fit by an external Compton model in the bright state, although day-to-day changes pose challenges to a simple one-zone model. All data from the SMARTS monitoring program are publicly available on our Web site.
black hole physics – BL Lacertae objects; general – galaxies; active – galaxies; jets – quasars; general