Evidence for two Lognormal States in Multi-wavelength Flux Variation of   FSRQ PKS 1510-089
  We present a systematic characterization of multi-wavelength emission from blazar PKS 1510-089 using well-sampled data at infrared(IR)-optical, X-ray and $\gamma$-ray energies. The resulting flux distributions, except at X-rays, show two distinct lognormal profiles corresponding to a high and a low flux level. The dispersions exhibit energy dependent behavior except for the LAT $\gamma$-ray and optical B-band. During the low level flux states, it is higher towards the peak of the spectral energy distribution, with $\gamma$-ray being intrinsically more variable followed by IR and then optical, consistent with mainly being a result of varying bulk Lorentz factor. On the other hand, the dispersions during the high state are similar in all bands expect optical B-band, where thermal emission still dominates. The centers of distributions are a factor of $\sim 4$ apart, consistent with anticipation from studies of extragalactic $\gamma$-ray background with the high state showing a relatively harder mean spectral index compared to the low state. 
Pankaj Kushwaha (1, 5), Sunil Chandra (2), Ranjeev Misra (1), S.   Sahayanathan (3), K. P. Singh (2), K. S. Baliyan (4) ((1)...
astro-ph.HE astro-ph.GA