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A.P. Marscher, S.G. Jorstad (Boston U.), M.F. Aller (U. Michigan), I.M. McHardy (U. Southampton), T.J. Balonek (Colgate U.)
We are continuing our combined RXTE X-ray, VLBA imaging (at 43 GHz), optical (several observatories), and radio (University of Michigan Radio Astronomy Observatory) monitoring of the quasars 3C 279 and PKS 1510-089, and have started similar monitoring of 3C 273. X-ray flares in 3C 279 and PKS 1510-089 are associated with ejections of superluminal components. In addition, there is a close connection between the optical and X-ray variability of 3C 279. There is a strong correlation between the 14.5 GHz and X-ray variability of PKS 1510-089 in 1997 and 1998 (with the radio leading the X-ray) that becomes weaker in subsequent years. X-ray fluctuations occur on a variety of timescales in 3C 273, with a major prolonged outburst in mid-2001.
The lead author will discuss the correlations in terms of inverse Compton models for the X-ray emission coupled with synchrotron models for the lower-frequency radiation. Synchrotron self-Compton models can explain the ``reverse'' time lag in PKS 1510-089 as well as the variable correlation between the X-ray variations and those at lower frequencies in this object and in 3C 279.
This work is supported in part by NASA through the Astrophysical Data Program and by the National Science Foundation through grants AST-9802941 and AST-0098579.