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On the Correlation between Radio Properties and Black Hole Mass of Quasars

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Chinese Journal of Astronomy and Astrophysics 2003年第3期3卷 212-224页

作者： Xue-Guang Zhang, Ting-Gui Wang and You-Jun LuCenter for Astrophysics, and Department of Astronomy and Applied Physics, University of Science and Technology of China, Hefei 230026 zxg@*** Center for Astrophysics and Department of Astronomy and Applied Physics University of Science and Technology of China Hefei 230026

The question whether the radio properties of quasars are related to the massof the central black hole or the accretion rate is important for our understanding of the formationof relativistic jets, but no consensus has been reached from statistical analyses. Using two largequasar samples, one radio-selected, one optical-selected, we re-examined these relations and findthat previous differences between radio- and optical- selected samples can be ascribed, at leastpartly, to the effect of the narrow line component. All previous claimed correlations are muchweaker, if exist at all.

关键词： galaxies: active galaxies: nuclei quasars black hole

Possible evidence of destroying small PAH particles by radiation from AGNs

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Research in Astronomy and Astrophysics 2015年第2期15卷 199-206页

作者： Qi-Chen Feng Jing Wang Jian-Yan Wei National Astronomical Observatories Chinese Academy of Sciences University of Chinese Academy of Sciences

The issue of destroying small polycyclic aromatic hydrocarbon （PAH） par- ticles by radiation from AGNs is examined through optical narrow-emission line ra- tios of a sample of type II AGNs. We find that narrow-line ratios [OI]λ6300/Ha and [SII]λ6716, λ6731/Hα have prominent correlations with the PAH 11.3/7.7 ratio in our selected sample of AGNs. Because of the marginal （and in some cases no） dependence of the PAH ratio on the gas metallicity, a possible explanation for the correlations is the destruction of small PAH particles by the hard ionizing field associated with the AGNs.

关键词： infrared: ISM quasars: emission lines galaxies: active galaxies: AGN methods: statistical

The Binary Black Hole Scenario for the BL Lacertae Object AO 0235+16

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Chinese Journal of Astronomy and Astrophysics 2003年第6期3卷 513-525页

作者： G.E.Romero Jun-HuiFan S.E.Nuza InstitutoArgentinodeRadioastrononia C.C.5（1894）VillaElisaBs.As.Argentina CenterforAstrophysics GuangzhouUniversityGuangzhou510400 DepartamentodeFisicaJ.J.Giambiagi FCENUBAPabellon1CiudadUniversitaria1428BuenosAiresArgentina

Recent analysis of the long term radio light curve of the extremely variableBL Lacertae object AO 0235+16 by Raiteri et al. have revealed the presence of recurrent outburstswith a period of ～ 5.7 +- 0.5 yr. Periodicity analysis of the optical light curve also showsevidence for a shorter period. Here we discuss whether such a behavior can be explained by a binaryblack hole model where the accretion disk of one of the supermassive black holes is precessing dueto the tidal effects of the companion. We estimate the mass of the accreting hole and analyzeconstraints on the secondary mass and the orbital parameters of the system. It is possible toprovide a viable interpretation of the available multiwavelength data.

关键词： galaxies: active BL lacertae objects: individual: AO 0235+16 -gamma rays:theory black hole physics

Fermi/LAT observations of lobe-dominant radio galaxy 3C 207 and possible radiation region of γ-rays

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Research in Astronomy and Astrophysics 2018年第6期18卷 93-98页

作者： Sheng-Chu Guo Hai-Ming Zhang Jin Zhang En-Wei Liang Guangxi Key Laboratory for Relativistic Astrophysics Department of Physics Guangxi University Key Laboratory of Space Astronomy and Technology National Astronomical Observatories Chinese Academy of Sciences

3 C 207 is a lobe-dominant radio galaxy with a one sided jet and bright knots, spanning a kpcMpc scale, which have been resolved in the radio, optical and X-ray bands. This target was confirmed as a γ-ray emitter with Fermi/LAT, but it is uncertain whether the γ-ray emission region is the core or knots due to the low spatial resolution of Fermi/LAT. We present an analysis of its Fermi/LAT data acquired during the past 9 years. Different from the radio and optical emission from the core, it is found that theγ-ray emission is steady without detection of flux variation at over a 2σ confidence level. This likely implies that the γ-ray emission is from its knots. We collect the radio, optical and X-ray data of knot-A,the closest knot from the core at 1.4′′, and compile its spectral energy distribution(SED). Although the single-zone synchrotron+SSC+IC/CMB model that assumes knot-A is at rest can reproduce the SED in the radio-optical-X-ray band, the predicted γ-ray flux is lower than the LAT observations and the derived magnetic field strength deviates from the equipartition condition by 3 orders of magnitude. Assuming that knot-A is moving relativistically, its SED from radio to γ-ray bands would be represented well with the single-zone synchrotron+SSC+IC/CMB model under the equipartition condition. These results likely suggest that the γ-ray emission may be from knot-A via the IC/CMB process and the knot should have relativistical motion. The jet power derived from our model parameters is also roughly consistent with the kinetic power estimated with radio data.

关键词： galaxies: active galaxies: jets radiation mechanisms: non-thermal galaxies: individual(3C 207)

The Origin of Infrared Emission from the Infrared Luminous Galaxy NGC 4418

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Chinese Journal of Astronomy and Astrophysics 2005年第2期5卷 117-125页

作者： Lei Shi and Qiu-Sheng Gu Department of Astronomy, Nanjing University, Nanjing 210093 qsgu@*** Department of Astronomy Nanjing University

We present a study of the origin of infrared (IR) emission in the opticallynormal, infrared luminous galaxy NGC 4418. By decomposing the stellar absorption features andcontinua in the range of 3600-8000 A from the Sloan Digital Sky Survey into a set of simple stellarpopulations, we derive the stellar properties for the nuclear region of NGC 4418. We compare theobserved infrared luminosity with the one derived from the starburst model, and find thatstar-forming activity contributes only 7% to the total IR emission, that as the IR emission regionis spatially very compact, the most possible source for the greater part of the IR emission is adeeply embedded AGN, though an AGN component is found to be unnecessary for fitting the opticalspectrum.

关键词： galaxies: general galaxies: active galaxies: stellar content galaxies:individual (NGC 4418)

Weighing super-massive black holes with narrow Fe Kα line

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Science China(Physics,Mechanics & Astronomy) 2011年第7期54卷 1354-1358页

作者： JIANG Peng WANG JunXian SHU XinWen CAS Key Laboratory for Research in galaxies and Cosmology Department of Astronomy University of Science and Technology of China Hefei 230026 China

It has been suggested that the narrow cores of the Fe Ka emission lines in active Galactic Nuclei （AGNs） are likely produced in the torus, the inner radius of which can be measured by observing the lag time between the V and K band flux variations. In this paper, we compare the virial products of the infrared time lags, and the narrow Fe Ka widths for 10 type 1 AGNs, with the black hole masses from other techniques. We found the narrow Fe Ka line width is in average 2.6＋0.9-0.4 times broader than expected, assuming an isotropic velocity distribution of the torus at the distance measured by the infrared lags. We propose the thick disk model of the torus may explain the observed larger line width. Another possibility is the contamination by emission from the broad line region or the outer accretion disk. Alternatively, the narrow iron line might originate from the inner most part of the obscuring torus within the sublimation radius, while the infrared emission may be from the outer cooler part. We note the correlations between the black hole masses based on this new technique and those based on other known techniques are statistically insignificant. We argue that this could be attributed to the small sample size and the very large uncertainties in the measurements of iron K line widths. The next generation of X-ray observatories could help verify the origin of the narrow iron Ka line and the reliability of this new technique.

关键词： black hole physics galaxies: active galaxies: nuclei galaxies: Seyfert X-rays: galaxies infrared: galaxies

Schechter Function Model for the QSO Luminosity Function from the SDSS DR7

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International Journal of Astronomy and Astrophysics 2016年第3期6卷 247-253页

作者： Salam Ajitkumar Singh I. Ablu Meitei K. Yugindro Singh Department of Physics Manipur University Imphal India Department of Physics Modern College Imphal India

A study of the optical luminosity function of Quasi Stellar Objects (QSOs) and its evolution with redshift is carried out using the data from the Sloan Digital Sky Survey Data Release Seven (SDSS DR7). It is shown that the observed QSO luminosity function is well fitted by a Schechter function model of the form , where is the break or characteristic luminosity with luminosity evolution characterized by a second order polynomial in red shift. The best fit parameters are determined by using the Levenberg-Marquardt method of nonlinear least square fit.

关键词： galaxies: active Quasars: General galaxies: Luminosity Function