Lohfink, Anne M., Reynolds, Christopher S., Jorstad, Svetlana G., Marscher, Alan P., Miller, Eric D., Aller, Hugh, Aller, Margo F., Brenneman, Laura W., Fabian, Andrew C., Miller, Jon M., Mushotzky, Richard F., Nowak, Michael A., and Tombesi, Francesco. 2013. "An X-Ray View of the Jet Cycle in the Radio-loud AGN 3C120." The Astrophysical Journal, 772 83. https://doi.org/10.1088/0004-637X/772/2/83.
We present a study of the central engine in the broad-line radio galaxy 3C120 using a multi-epoch analysis of a deep XMM-Newton observation and two deep Suzaku pointings (in 2012). In order to place our spectral data into the context of the disk-disruption/jet-ejection cycles displayed by this object, we monitor the source in the UV/X-ray bands, and in the radio band. We find three statistically acceptable spectral models: a disk-reflection model, a jet model, and a jet disk model. Despite being good descriptions of the data, the disk-reflection model violates the radio constraints on the inclination, and the jet model has a fine-tuning problem, requiring a jet contribution exceeding that expected. Thus, we argue for a composite jet disk model. Within the context of this model, we verify the basic predictions of the jet-cycle paradigm, finding a truncated/refilling disk during the Suzaku observations and a complete disk extending down to the innermost stable circular orbit during the XMM-Newton observation. The idea of a refilling disk is further supported by the detection of the ejection of a new jet knot approximately one month after the Suzaku pointings. We also discover a step-like event in one of the Suzaku pointings in which the soft band lags the hard band. We suggest that we are witnessing the propagation of a disturbance from the disk into the jet on a timescale set by the magnetic field.
