We have collected all available spectra and photometric data from the SDSS catalog for bright AGNs complied from the first three months of the Fermi large area telescope all-sky survey. Based on the 106 high-confidence and 11 low-confidence associated bright AGN list, the photometry data are collected from SDSS DR7 for 28 sources （12 BL Lacs and 16 FSRQs）, two of which are low-confidence associated bright AGNs. Among these 28 SDSS photometric sources, SDSS spectra are available for 20 sources （6 BL Lacs and 14 FSRQs）. The black hole masses MBH and the broad line region （BLR） luminosity were obtained for 14 FSRQs by measuring the line-widths and strengths of broad emission lines from the SDSS spectra. The broad emission line measurements of five FSRQs are presented for the first time in this work. The optical continuum emission of these 14 FSRQs is found to be likely dominated by the non-thermal jet emission by comparing the relationship between the broad Mg II line and continuum luminosity to that of radio-quiet AGNs. The black hole mass of the 14 FSRQs ranges from 10^8.2 M⊙ to 10^9.9 M⊙, with most of the sources larger than 10^9 M⊙. The Eddington ratio Lbol/LEdd ranges from 10-1＇5 to - 1. This implies that an optically thin, geometrically thick accretion disk may exist in these FSRQs.
We investigate the effects of various ways of injection of gas at the outer boundary in the numerical simulations of non-viscous accretion flows.We study three models.In Model A,we inject material around the equatorial plane.In Models B and C,fullrange θ injection is used(we employ spherical coordinates).In all three models,the injected material has the same density distribution with polar angle θ.From the equatorial region to the polar regions,angular momentum of the injected material of Model B decreases faster than that in Model C.For all of the models,after a transient episode of infall at the beginning of the simulations,the gas piles up in the equatorial regions outside the black hole and forms a thick torus bounded by a centrifugal barrier.We find that the accretion rates of Models B and C are more than ten times higher than that in Model A.In Model A,there is weak accretion only in the torus and outflows are found on the surface of the torus.In Model B,we find strong inflows on the surface of its torus,and the accretion in the torus is weak.In Model C,strong inflows also occur on the surface of its torus,but the accretion regions are narrower and there are strong outflows in its torus.In all of our models,the time-averaged density,pressure and angular momentum in the equatorial region can be described by a radial power law,with P ∝r-3/2,P ∝r-2 and l∝r0.
BU DeFu,YUAN Feng,WU MaoChun & YANG XiaoHong Key Laboratory for Research in Galaxies and Cosmology,Shanghai Astronomical Observatory,Chinese Academy of Sciences,Shanghai 200030,China
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.
A tight correlation between γ-ray and radio emission is found for a sample of BL Lacertae （BL Lac） objects detected by the Fermi Gamma-ray Space Telescope （Fermi） and the Energetic Gamma-Ray Experiment Telescope （EGRET）. The γ-ray emission of BL Lac objects exhibits strong variability, and the detection rate of γ-ray BL Lac objects is low, which may be related to the γ-ray duty cycle of BL Lac objects. We estimate the γ-ray duty cycle, δγ ≌ 0.11, for BL Lac objects detected by EGRET and Fermi. Using the empirical relation of γ-ray emission with radio emission and the estimated γ-ray duty cycle δγ, we derive the γ-ray luminosity function （LF） of BL Lac objects from their radio LE Our derived γ-ray LF of BL Lac objects can almost reproduce that calculated with the recently released Fermi bright active galactic nuclei （AGN） sample. Comparison of the derived LF of the γ-ray BL Lac objects in this work with that derived by Abdo et al. （2009a） requires the γ-ray duty cycle of BL Lac objects to be almost luminosity-independent. We find that - 45% of the extragalactic diffuse γ-ray background （EGRB） is contributed by BL Lac objects. Combining the estimate of the quasar contribution to the EGRB in the previous work, we find that 77% of the EGRB is contributed by BL Lac objects and radio quasars.
We report on the effects of isotropic thermal conduction in non-radiative collisionless accretion flows in two dimensions.In comparison to accretion flows without conduction,we find that the disk generally becomes cooler and thinner.Specifically,the magnitude of this effect depends on the kinetic viscosity coefficient.If it is proportional to density,the density profile of the accretion flow is flat,therefore the effect is not very obvious.But,if it is proportional to r1/2,as is usual for the "α" disk description,the density profile is steeper.Therefore,the effect will be much more obvious,with the temperature profile of the accretion flow becoming much flatter.This will have important observational consequences.
WU MaoChun,YUAN Feng & BU DeFu Key Laboratory for Research in Galaxies and Cosmology,Shanghai Astronomical Observatory,Chinese Academy of Sciences,Shanghai 200030,China
BL Lac object S5 2007+777 has been classified as a HYMOR(Hybrid Morphology radio source) for its hybrid FR I and FR II radio morphology.It is one of four BL Lac objects with a kpc scale extended X-ray jet.In this paper,we searched the unpublished European VLBI Network(EVN) archived high resolution data for this source,and present the high resolution radio structure.The EVN images all show a core-jet structure in 1.6,5 and 8 GHz.In combination with the VLA data in the literature,we found position angle differences(△PA) of about 10°-20° between pc and kpc scale jet structures.The brightness temperature estimated from multi-band EVN images are around 1011.2-1011.8 K,from which the Doppler factor ranges from 3.2 to 12.0.We found significant flux variations of the radio core in 1.6 and 5 GHz,from which we derived the variability in brightness temperature Tvar to be 1013.6 K and 1014.0 K,corresponding to the Doppler factors of 9.3 and 12.4,respectively.
WU ZhongZu1,3,GU MinFeng2 & CHEN YongJun2 1 College of Science,Guizhou University,Guiyang 550025,China
<Abstract>For a sample of 185 flat-spectrum radio quasars(FSRQs) constructed from the SDSS DR3 quasar catalog,we found a significant correlation between the synchrotron peak luminosity and both the black hole mass and Eddington ratio.This implies that the physics of its jet formation is not only tightly related with the black hole mass,but also with the accretion rate.We verify that the synchrotron peak luminosity can be a better indicator of jet emission than 5 GHz luminosity,through comparing the relationships between each of these two parameters and both black hole mass and Eddington ratio.The fundamental plane of black hole activity for our FSRQs is established as Lr ∝ L0x.80 ± 0.06 Mbh -0.04 ± 0.09 with a weak dependence on black hole mass,however,the scatter is significant.
GU MinFeng1 & CHEN ZhaoYu1,2 1 Key Laboratory for Research in Galaxies and Cosmology,Shanghai Astronomical Observatory,Chinese Academy of Sciences,Shanghai 200030,China
Based on the Sloan Digital Sky Survey DR6 （SDSS） and the ＇Millennium Simulation （MS）, we investigate the alignment between galaxies and large-scale structure. For this purpose, we develop two new statistical tools, namely the alignment correlation function and the cos（20）-statistic. The former is a two-dimensional extension of the traditional two-point correlation function and the latter is related to the ellipticity correlation function used for cosmic shear measurements. Both are based on the cross correlation between a sample of galaxies with orientations and a reference sample which represents the large-scale structure. We apply the new statistics to the SDSS galaxy catalog. The alignment correlation function reveals an overabundance of reference galaxies along the major axes of red, luminous （L 〉 ～L＊） galaxies out to projected separations of 60 h-lMpc. The signal increases with central galaxy luminosity. No alignment signal is detected for blue galaxies. The cos（2θ）-statistic yields very similar results. Starting from a MS semi-analytic galaxy catalog, we assign an orientation to each red, luminous and central galaxy, based on that of the central region of the host halo （with size similar to that of the stellar galaxy）. As an alternative, we use the orientation of the host halo itself. We find a mean projected misalignment between a halo and its central region of -25°. The misalignment decreases slightly with increasing luminosity of the central galaxy. Using the orientations and luminosities of the semi-analytic galaxies, we repeat our alignment analysis on mock surveys of the MS. Agreement with the SDSS results is good if the central orientations are used. Predictions using the halo orientations as proxies for cen- tral galaxy orientations overestimate the observed alignment by more than a factor of 2. Finally, the large volume of the MS allows us to generate a two-dimensional map of the alignment correlation function, which shows the reference galaxy distribution to be fl
A. FaltenbacherCheng LiSimon D. M. WhiteYi-Peng JingShu-De MaoJie Wang
