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M.F. Aller (U. Mich.), A.P. Marscher, S.G. Marchenko-Jorstad (IAA, Boston U.), I.M. McHardy (U. Southampton), H.D. Aller (U. Mich.)
We present results for the X-ray-bright superluminal AGN PKS 1510-089 (z=0.36) monitored weekly with the Rossi X-Ray Timing Explorer for the past four years in order to study the origin of X-ray emission from this extremely variable blazar. These RXTE data are compared with weekly cm-band flux and polarization observations from the Michigan 26-meter telescope, to identify correlated activity and associated frequency-dependent time delays for constraining X-ray emission models; and bi-monthly 7mm VLBA total and linearly polarized intensity imaging to identify temporal associations between X-ray events and the ejection of superluminal components and disturbances in the magnetic field, to test if the X-ray energy release is related to changes in the inner jet flow.
Both the X-ray (2-20 keV) and radio flux are highly variable on timescales of weeks. The VLBA mas structure is dominated by a bright core with a weak jet; both the ejection of very fast superluminal knots and changes in the fractional polarization and EVPA of the core on timescales of 1-4 months are identified. Two outbursts in 1997 are well-resolved in both the centimeter and X-ray bands. Both the strong temporal association and the similar outburst shape support a causal relation, and a discrete cross-correlation analysis identifies that the X-ray lags the radio by 16 days during the bursts. Starting in 1998 the behavior changes: the correlation is weaker with the X-ray possibly leading the radio by 6 days. During the full time window there is a correlation between bands as expected if the radio photons are upscattered to X-ray energies. The time correlations and difference between the flat X-ray spectral index (0.0\leq\alpha\leq0.5 where F\nu\propto\nu-\alpha), and the mm-wave synchrotron spectrum (\alpha\approx 0.8) are discussed within the framework of viable SSC models.
This work was supported in part by NASA grants NAG5-4244, \linebreak -4245, -7338, -7565, -9161, and -9162, by NSF grants AST-9802941 and -9900723, and by operating funds from U. Michigan.