Day-scale variability of 3C 279 and searches for correlations in gamma-ray, x-ray, and optical bands

Light curves of 3C 279 are presented in optical (R band), X-rays (RXTE/PCA) , and gamma rays (CGRO/ EGRET) for 1999 January-February and 2000 January-M arch. During both of those epochs the gamma -ray levels were high and all t hree observed bands demonstrated substantial variation, on timescales as sh ort as 1 day. Correlation analyses provided no consistent pattern, although a rather significant optical/gamma -ray correlation was seen in 1999, with a gamma -ray lag of similar to2.5 days, and there are other suggestions of correlations in the light curves. For comparison, correlation analysis is also presented for the gamma -ray and X-ray light curves during the large g amma ray flare in 1996 February and the two gamma -bright weeks leading up to it; the correlation at that time was strong, with a gamma -ray/X-ray off set of no more than 1 day.