T. F. Yi

The Periodicity Analysis of the Light Curve of 3C 279 and Implications for the Precession Jet

We have analyzed the light curves of 3C 279 at 22 GHz, 37 GHz, optical R band, and X-ray (2-10 KeV), and found evidence of quasi-periodic outbusts. The light curves show that 3C 279 is an extremely active object. A period of P = 130:6 +/- 1:3 days was consistently confirmed by three methods: the power-spectrum method, the discrete correlation function (DCF) method, and the Jurkevich method. Based on the relationship between observed period Pobs and the precession period Pp given by Rieger and our result, the precession period of jet in 3C 279 is P(p) similar or equal to 29.6 yr, which is completely consistent with the precession period of jet of about 30 yr obtained by Carrara et al.. This suggests that there is a precession jet in 3C 279 and the variability period of about 130.6 days that we obtained is most likely caused by the helical motion of the jet.

ESTIMATION OF THE VISCOSITY PARAMETER IN ACCRETION DISKS OF BLAZARS

For an optical monitoring blazar sample set whose typical minimum variability timescale is about 1 hr, we estimate a mean value of the viscosity parameter in their accretion disk. We assume that optical variability on timescales of hours is caused by local instabilities in the inner accretion disk. Comparing the observed variability timescales to the thermal timescales of alpha-disk models, we could obtain constraints on the viscosity parameter (alpha) and the intrinsic Eddington ratio (L(in)/L(Edd) = (m) over dot), 0.104 = 0.1) by numerical simulations in which magnetohydrodynamic turbulence is driven by the saturated magnetorotational instability.

Multiband Variability Analysis of 3C 454.3 and Implications for the Center Structure

We have analyzed the light curves of 3C 454.3 at the infrared, optical, soft X-ray (0.3-10 keV), and γ-ray (0.1-300 GeV) waveband, and found the evidence of quasi-periodicity. The light curves show that 3C 454.3 is a strongly active object. A period signal of P = 210.8 ± 12.1 days is confirmed by two methods consistently: the Lomb-Scargle periodogram and the Jurkevich method. The variations of the infrared, optical, soft X-ray, and γ-ray are well correlated, which suggests that these seven band emissions originate from the same population of electrons in the jet. The multifrequency variations in the emission fluxes of 3C 454.3 may be caused by the nonballistic helical motion of emitting components in the jet, which has the precession and the helical magnetic field. Moreover, these provide some evidence for the existence of a supermassive binary black hole (SMBBH) system in the center of 3C 454.3.

Multiband Variability Analysis of Mrk 421

We have assembled the historical variability data of Mrk 421 at radio 15 GHz, X-ray and gamma-ray bands, spanning about 6.3, 10.3 and 7.5 yr, respective- ly. We analyzed the variability by using three methods. The results indicated that there is a period of 287.6 +- 4.4 days for 15 GHz, 309.5 +- 5.8 days for X- ray and 283.4+- 4.7 days for gamma-ray, respectively. This period can be reasonably explained by the nonballistic helical motion of the emitting material. The cor- relation analysis suggested that the variabilities of radio 15 GHz, X-ray and 0-ray are remarkable correlated, and the emission of radio 15 GHz lags behind that of X-ray, and the X-ray flux lags behind the gamma-ray. This suggests that the gamma-ray derives from inverse Compton (IC) scattering of the synchrotron photons, supporting the synchrotron self-Compton (SSC) model. Moreover, the time delay between different wavebands could be explained by the shock-in-jet models, in which a moving emission region produces the radio to gamma-ray activity, implying that the emission region of gamma-ray is closer to the center than ones of X-ray and radio emission.

Curvature of the spectral energy distribution, the inverse Compton component and the jet in Fermi 2LAC blazars

We fit the spectral energy distributions (SEDs) of members of a large sample of Fermi 2LAC blazars to synchrotron and inverse Compton (IC) models. Our main results are as follows. (i) As suggested by previous works, the correlation between peak frequency and curvature can be explained by statistical or stochastic particle acceleration mechanisms. For BL Lacs, we find a linear correlation between synchrotron peak frequency and its curvature. The slope of the correlation is consistent with the stochastic acceleration mechanisms and confirm previous studies. For FSRQs, we also find a linear correlation, but its slope cannot be explained by previous theoretical models. (ii) We find a significant correlation between IC luminosity and synchrotron luminosity. The slope of the correlation of FSRQs is consistent with the EC process. And the slope of the correlation of BL Lac is consistent with the SSC process. (iii) We find several significant correlations between IC curvature and several basic parameters of blazars (black hole mass, broad line luminosity, the Lorentz factor of jet). We also find significant correlations between bolometric luminosity and these basic parameters of blazars which suggest that the origin of jet is a mixture of the mechanisms proposed by Blandford

The Radio and

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Znajek and by Blandford

-ray Variability Analysis of S5 0716+714

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The correlations of multi-wave band luminosity and BLR luminosity in Fermi 2LAC blazars

Payne.

On estimators of the jet bolometric luminosity of Fermi 2LAC blazars

We have studied the variability of S5 0716+714 at radio 15xa0GHz and γ