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Characteristic X-ray Variability of TeV Blazars: Probing the Link between the Jet and the Central Engine

Jun Kataoka·Tadayuki Takahashi·Stefan J. Wagner·Naoko Iyomoto·Philip G. Edwards·Kiyoshi Hayashida·Susumu Inoue·Greg M. Madejski·Fumio Takahara·Chiharu Tanihata·Nobuyuki Kawai
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Abstract

We have studied the rapid X-ray variability of three extragalactic TeV gamma-ray sources; Mrk 421, Mrk 501 and PKS 2155-304. Analyzing the X-ray light curves obtained from ASCA and/or RXTE observations between 1993 and 1998, we have investigated the variability in the time domain from 10^3 to 10^8 sec. For all three sources, both the power spectrum density (PSD) and the structure function (SF) show a roll-over with a time-scale of the order of 1 day or longer, which may be interpreted as the typical time-scale of successive flare events. Although the exact shape of turn-over is not well constrained and the low-frequency (long time-scale) behavior is still unclear, the high-frequency (short time-scale) behavior is clearly resolved. We found that, on time-scales shorter than 1 day, there is only small power in the variability, as indicated by a steep power spectrum density of f^{-2~-3}. This is very different from other types of mass-accreting black-hole systems for which the short time-scale variability is well characterized by a fractal, flickering-noise PSD (f^{-1~-2}). The steep PSD index and the characteristic time-scale of flares imply that the X-ray emitting site in the jet is of limited spatial extent; D > 10^{17} cm distant from the base of the jet, which corresponds to > 100 Schwarzschild radii for 10^{7-10} M_solar black-hole systems.

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Jun Kataoka, Tadayuki Takahashi, Stefan J. Wagner, Naoko Iyomoto, Philip G. Edwards, Kiyoshi Hayashida, Susumu Inoue, Greg M. Madejski, Fumio Takahara, Chiharu Tanihata, Nobuyuki Kawai. 2001-05-02. Characteristic X-ray Variability of TeV Blazars: Probing the Link between the Jet and the Central Engine. https://doi.org/10.1086/322442

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