We have collected an up-to-date sample of 123 superluminal sources （84 quasars, 27 BL Lac objects and 12 galaxies） and calculated the apparent velocities （βapp） for 224 components in the sources with the A-CDM model. We checked the relationships between their proper motions, redshifts,βapp and 5 GHz flux densities. Our analysis shows that the radio emission is strongly boosted by the Doppler effect. The superluminal motion and the relativistic beaming boosting effect are, to some extent, the same in active galactic nuclei.
The correlations between broad-line emission,polarization,and core-dominance parameters are investigated for a sample of 148 blazars(BL Lacertae objects-BLs and flat spectrum radio quasars-FSRQs). An anti-correlation between the broad-line luminosity and the linear polarization is found. The broad-line and polarization relation can be explained by using a relativistic beaming model,which perhaps suggests that BL Lacs and FSRQs are a single class. We also investigated the relation between the ratio of the broad-line luminosity to the Eddington luminosity and linear polarization,and that between the ratio of the broad-line luminosity to the Eddington luminosity and the core-dominance parameter.
YANG JiangHe 1,2 ,FAN JunHui 2,3 & YANG RuShu 1 1 Department of Physics and Electronics Science,Hunan University of Arts and Science,Changde 415000,China
Hawking radiation is viewed as a tunnelling process. In this way the emission rates of massless particles and massive particles tunnelling across the event horizon of general stationary axisymmetric black holes are calculated, separately. The emission spectra of these two different kinds of outgoing particles have the same functional form and both are consistent with an underlying unitary theory.
射电星系根据其在178MHz处的光度可以分为两类,即Fanaroff-Riley type Is(FRIs)和Fanaroff-Riley type IIs(FRIIs),而且FRIs的光度要低于FRIIs(Fanaroff&Riley1974).从SIMBAD网站上找到了许多个光学星等多于两个波段的源.在星等转化为流量密度时考虑了银河系修正,然后对于这些流量密度进行线性拟合,得到各个源的光学谱指数.对于这些谱指数,取它们的取值范围在-2到3之间,且α≥2Δα,最终得到153个源可用(61FRIs和92FRIIs).对FRIs和FRIIs的光学谱指数分布进行高斯拟合,发现FRIs的平均光学谱指数等于1.60±0.66,大于FRIIs的值1.13±1.09.然后我们对这两类源进行K-S检验,发现这两类源来自同一母体的概率是4.73E-6,这可以说明这两类源在光学波段可以被区分开.
Gamma-ray bursts(GRBs) are divided into two classes according to their durations.We investigate if the softness of bursts plays a role in the conventional classification of the objects.We employ the BATSE(Burst and Transient Source Experiment) catalog and analyze the duration distributions of different groups of GRBs associated with distinct softness.Our analysis reveals that the conventional classification of GRBs with the duration of bursts is influenced by the softness of the objects.There exists a bimodality in the duration distribution of GRBs for each group of bursts and the time position of the dip in the bimodality histogram shifts with the softness parameter.Our findings suggest that the conventional classification scheme should be modified by separating the two well-known populations in different softness groups,which would be more reasonable than doing so with a single sample.According to the relation between the dip position and the softness parameter,we get an empirical function that can roughly set apart the short-hard and long-soft bursts:SP =(0.100 ± 0.028) T-(0.85 0.18) 90,± where SP is the softness parameter adopted in this paper.
In this paper, we use a method to dctermine some basic parameters for the γ-ray loud blazars. The parameters include the central black mass （M）, the boosting factor （δ）, the propagation angle （Ф）, the distance along the axis to the site of the γ-ray production （d）. A sample including 32 γ-ray loud blazars with available variability time scales has been used to discuss the above properties. In this method, the γ-ray energy, the emission size and the property of the accretion disc determine the absorption effect. If we take the intrinsic γ-ray luminosity to be λ times the Eddington luminosity, i.e. Lγ^in =λLEdd, then we have the following results： the mass of the black hole is in the range of （0.59 - 67.99） ×10^7M⊙ （λ = 1.0） or （0.90 - 104.13） × 10^7M⊙ （λ = 0.1）; the boosting factor （5） in the range of 0.16 - 2.09（λ = 1.0） or 0.24 - 2.86 （λ = 0.1）; the angle （Ф） in the range of 9.53°- 73.85° （λ =1.0） or 7.36° - 68.89° （λ = 0.1）; and the distance （d/Rg） in the range of 22.39 - 609.36 （λ = 1.0） or 17.54 - 541.88 （λ = 0.1）.
We analyze the radio spectral index of blazars from the University of Michigan Radio Astronomy Observatory database,and find that there exists quasiperiodic activity in 2251＋158.The long-term periodicity analysis is accomplished by three methods,which are the Jurkevich method（Jurkevich）,the discrete correlation function（DCF）,and the Periodogram method（P）.The results show that 2251＋158 has two strong periodicities,which are P1=6.3±1.1 yr and P2=3.8±1.2 yr.
The light curve data from 1894 to 2008 are compiled for the BL Lacertae object OJ 287 from the available literature. Periodicity analysis methods （the Discrete Correlation Function-DCF, the Jurkevich method, the power spectral （Fourier） analysis, and the CLEANest method） are performed to search for possible periodicites in the light curve of OJ 287. Significance levels are given for the possible periods. The analysis results confirm the existence of the 12.2 ± 0.6 yr time scale and show a hint of a -53 yr time scale. The 12.2 ± 0.6 yr period is used as the orbital period to investigate the supermassive binary black hole system parameters.
Jun-Hui FanYi LiuBo-Chun QianJun TaoZhi-Qiang ShenJiang-Shui ZhangYong HuangJin Wang
We estimate black hole masses and Edenton ratios for a sample of 81 young radio galaxies,which includes 42 compact steep-spectrum(CSS) and 39 gigahertz-peaked spectrum(GPS) sources.We find that the average black hole(BH) mass of these young radio galaxies is〈log Mbh〉-8.3,which is less than that of radio loud QSOs and low redshift radio galaxies(〈 log Mbh〉-9.0).The CSS/GPS sources have relatively high Eddington ratios,with an average value of〈log Lbol/LEdd〉=-0.75,which are similar to those of narrow line Seyfert 1 galaxies(NLS1s).This suggests that young radio galaxies may not only be in the early stages of their radio activity,but also in the early stage of their accretion activity.We find that the young radio galaxies,as a class,systematically deviate from the Mbh-σ relation defined by nearby inactive galaxies,when using σ[O III] as a surrogate for stellar velocity dispersion σ.We also find that the deviation of the [O III] line width,Δσ =σ[O III]-σ[pred],is correlated with the Eddington ratio;sources with Lbol/LEdd-1 have the largest deviations,which are similar to those of radio quiet QSOs/NLS1s(i.e.,sources in which the radio jets are absent or weak),and where σ[pred] is calculated from the Tremaine et al.relation using our estimated BH masses.A similar result has been obtained for 9 linear radio Seyfert galaxies.On the basis of these results,we suggest that,in addition to the possible jet-gas interactions,accretion activities may also play an important role in shaping the kinematics of the narrow [O III] line in young radio galaxies.
