A possible precessing nozzle and the Lense-Thirring effect in blazar 3C 454.3

The kinematics of superluminal components in blazar 3C 454.3 are studied.Nine components are included:superluminal knots R1,R2,R3,R4,A,B,C and D(from Britzen et al.2013) and C4(from Pauliny-Toth 1998).We find that their kinematics derived from VLBI observations can be consistently interpreted in terms of a jet precession scenario with a period of about 14.5 yr.We discuss the model fits of their trajectory,distance from the core and apparent velocity.We show that the bulk Lorentz factor(in the range 4 to 15) derived for these components does not have any dependence on the phase of the precession(or position angle for ejection).The LenseThirring effect is assumed to interpret the precession of the jet nozzle.The results obtained for blazar 3C 454.3 are only suggestive.They are not unique and have yet to be tested,but they might be useful for understanding the kinematics of superluminal components in blazars and for disentangling different mechanisms and factors.     

A Possible Periodicity in the Radio Light Curves of 3C 454.3

During the period 1966.5–2006.2 the 15GHz and 8GHz light curves of 3C 454.3 (z = 0.859) show a quasi-periodicity of ～12.8 yr (～6.9 yr in the rest frame of the source) with a double-bump structure. This periodic behaviour is interpreted in terms of a rotating double-jet model in which the two jets are created from the black holes of a binary system and rotating with the period of the orbital motion. The periodic variations in the radio fluxes of 3C 454.3 are suggested to be mainly due to the lighthouse effects (or the variation in Doppler boosting) of the precessing jets caused by the orbital motion. In addition, variations in the rate of mass accreting onto the black holes may be also involved.     

Multifrequency Polarization Variations in the Quasar 0917＋624

We present a detailed analysis of multi-frequency observations of linear polarization in the intraday variable quasar 0917+624 (z = 1.44). The observations were made in May 1989 at five frequencies (1.4, 2.7, 5.0, 8.3 and 15GHz) with the VLA and the Effelsberg 100 m-telescope and in December 1988 at two frequencies (2.7 and 5.0 GHz) with the latter. It is shown that the relationship between the variations of the polarized and total flux density is highly wavelength dependent, and the multi-frequency polarization behavior may be essential for investigating the mechanisms causing these variations. It is shown that the variations observed at 20 cm can be interpreted in terms of refractive interstellar scintillation. However, after subtracting the variation due to scintillation, three 'features' emerged in the light-curve of the polarized flux density, indicating an additional variable component. Interestingly, these features are shown to be correlated with the variations at 2-6 cm, thus indicating that thes     

致密射电源的快速偏振变化和星际闪烁模型

以类星体０９１７＋６２４中１９８９年５月观测到的ＩＤＶ事件为实例,尝试提出一个４成分模型（１个稳定成分和 ３个闪烁成分）以充分解释在 ６ ｃｍ波长上观测到的偏振变化,包括流量和偏振流量的相关性和反相关性以及它们之间的快速转化．对于 ２０ ｃｍ波长上观测到的偏振变化,３成分模型（１个稳定成分和３个闪烁成分）已足以解释全部现象．文中提出的闪烁模型在解释ＩＤＶ事件的偏振变化方面改进了以前的模型拟合．     

BLO0716＋71非热辐射的喷流模型：从射电到γ射线

本文探讨用相对论喷流模型解释ＢＬ Ｌａｃ天体０７１６＋７１从射电到γ射线的整修电磁波段的非热辐射。喷流的结构分两个区域描述：内区具有抛物线结构，喷流是加速的；外区具有圆锥形结构，喷流速度恒定。相对论电子的密度和最高能量，以及磁场等参数随距离向外按幂律下降。在此模型中，射电至紫外线起源于相对论电子的同步辐射，而高能的Ｘ射线和γ射线则起源于自康普顿散射。辐射的频率越高，产生区域越靠近中央能源机器。辐射     

γ射线源PKS 0528＋134毫米波—射电大爆发的分析

利用作者１９９６年提出的爆发主入模型,分析了１９９１－１９９３年期间观测到的ＰＫＳ０５２８＋１３４的两个毫米波－射电大爆发,把理论的流量变化线性和１２个频率（从２３０ＧＨｚ到２．３ＧＨｚ）上的预测曲线进行了比较。结果表明,该模型相当好地解释了在相当宽阔的频率范围（￣５０：１）内观测到的流量密度变化。     

A new three-stage evolution model for millimeter to centimeter wavelength outbursts in BL Lacertae

The multi-frequency light curves of BL Lacertae during 1997.5 – 1999.5 have been modeled by four outbursts,each having a 3-stage evolution in the (S m,νm) plane with distinct rising–plateau–decaying phases.It is shown that the observed light curves can be well fitted for the eight frequencies from 350GHz to 4.8GHz.The main characteristics of the model-fitting are: (1) the outbursts are found to have very flat spectra with an optically thin spectral index α (defined as Sν∝ν-α) of about 0.15.This is consisten...     

Refractive Focusing of Interstellar Clouds and Intraday Polarization Angle Swings

Intraday variations of compact extragalactic radio sources in flux density and po- larization are generally interpreted in terms of refractive scintillation from the continuous interstellar medium of our Galaxy. However, continuous polarization angle swings of～180° (for example, the one observed in the QSO 0917 624) could not be interpreted in this way. Qian et al. have shown that the polarization angle swing observed in the QSO 1150 812 can be explained in terms of focusing-defocusing effect by an interstellar cloud, which occults two closely-placed polarized components. Here we further show that the polarization angle swing event observed in the QSO 0917 624 can also be explained in this way. We also found evidence for the cloud eclipsing a non-polarized (core) component during a short period out- side the swing. A particular (and specific) plasma-lens model is proposed to model-fit the polarization swing event of 0917 624. Some physical parameters related to the plasma-lens and the source components are estimated. The brightness temperatures of the two lensed components are estimated to be ～1.6×1013 K. Thus bulk relativistic motion with a Lorentz factor less than ～20 may be sufficient to avoid the inverse - Compton catastrophe.     

High Brightness Temperatures in IDV Sources

High brightness temperatures are a characteristic feature of IntraDay Variability (IDV) of extragalactic radio sources. Recent studies of the polarization properties of some IDV sources (e.g., 1150 812, PKS 0405-385 and 0716 714) have shown that these sources harbor several compact IDV components with angular sizes of -10-30/uas and very high polarizations (of up to -50%-70%). These results indicate the possibility of the existence of uniform magnetic fields in the IDV components. We investigate the incoherent synchrotron and self- Compton radiation of an anisotropic distribution of relativistic electrons which spin around the magnetic field lines at small pitch angles. The brightness temperature limit caused by second-order Compton losses is discussed and compared to the brightness temperatures derived from energy equipartition arguments. It is found that anisotropic distributions of electrons moving in ordered magnetic fields can raise the equipartition and Compton brightness temperatures by a factor of up to -3-5. This would remove some of the difficulties in the interpretation of extremely high intrinsic brightness temperatures of > 1012 K (or apparent brightness temperatures of - 1014 K with a Doppler factor of -30).     

A possible precessing nozzle and the Lense-Thirring effect inblazar 3C 454.3

The kinematics of superluminal components in blazar 3C 454.3 are studied.Nine components are included： superluminal knots R1, R2, R3, R4, A, B, C and D（from Britzen et al. 2013） and C4 （from Pauliny-Toth 1998）. We find that their kine-matics derived from VLBI observations can be consistently interpreted in terms of ajet precession scenario with a period of about 14.5 yr. We discuss the model fits oftheir trajectory, distance from the core and apparent velocity. We show that the bulkLorentz factor （in the range 4 to 15） derived for these components does not have anydependence on the phase of the precession （or position angle for ejection）. The Lense-Thirring effect is assumed to interpret the precession of the jet nozzle. The resultsobtained for blazar 3C 454.3 are only suggestive. They are not unique and have yet tobe tested, but they might be useful for understanding the kinematics of superluminalcomponents in blazars and for disentangling different mechanisms and factors.