Narrow-line Seyfert 1(NLS1) galaxies are believed to harbor low-mass black holes accreting at high rates,and they are therefore important targets when studying the nature of black hole growth,galaxy evolution,and accretion physics.We have rigorously studied the physical properties of a sample of NLS1 galaxies.We briefly review previous findings and present new results,including:(1) The locus of NLS1 galaxies on the MBH-σ plane,which we find to follow the relation of non-active galaxies after removing objects obviously dominated by outflows.(2) The presence of "blue outliers" which hint at extreme outflows as they would be predicted from merger models.(3) More subtle evidence for winds and outflows across the whole NLS1 population.(4) New correlations and trends which link black hole mass,Eddington ratio and physical parameters of the emission-line region.A new element is added to the eigenvector 1 space based on a principal component analysis,which aims at identifying the main drivers of AGN correlation properties.
Pulse widths of standard pulse profiles for 262 pulsars were measured by using the Urumqi 25 m radio telescope at 1.54 GHz.For the simplest case of circular emission beam,we applied Monte Carlo simulations to the pulse width distribution.Different density functions of magnetic inclination angle α and observer angle ξ were considered.Using Kolmogorov-Smirnov tests,we derived the most probable distribution for α and ξ.
CHEN JianLing1,2,WANG Na1,YUAN JianPing1,2,WANG HongGuang3,YAN WenMing1,2 & LIU ZhiYong1 1 Urumqi Observatory,National Astronomical Obsevatories,Chinese Academy of Sciences,Urumqi 830011,China
We present the X-ray variability properties of the X-ray and TeV bright blazar Mrk 421 with a-60 ks long XMM-Newton observation performed on November 9-10,2005.The source experienced a pronounced flare,of which the inter-band time lags were determined with a very high confidence level.The soft(0.6-0.8 keV) X-ray variations lagged the hard(4-10 keV) ones by 1.09+0.11-0.12 ks,and the soft lag increases with increasing difference in the photon energy.The energy-dependent soft lags can be well fitted with the difference of the energy-dependent cooling timescales of the relativistic electron distribution responsible for the observed X-ray emission,which constrains the magnetic field strength and Doppler factor of the emitting region to be Bδ 1/3-1.78 Gauss.
ZHANG YouHong1,HOU ZhengTian2,SHAO Li3 & ZHANG Peng1 1 Department of Physics and Tsinghua Center for Astrophysics(THCA),Tsinghua University,Beijing 100084,China
This paper presents a mathematical method for de-dispersion of average pulsar profiles.We applied this method to four dispersed pulsar profiles.The results revealed that this method significantly removed the dispersion broadening and the pulse widths were reduced by about 7% to 27%,depending on the magnitude of the pulsar dispersion measure.
There are significant correlations between the broad line region luminosity LBLR,the quantity Δmax(maximum of Δ≡log[(Fν)cm/(Fν)mm]) and redshift z.There are strong correlations between the extended radio luminosity PE,LBLR and Δmax.Our results indicate that FSRQs with higher mass accretion rate M and black hole spin j occur in the earlier,highly luminous,violent phase of the galactic sequence,and BL Lacs with lower M and j occur in the lower luminous,later phase of the galactic sequence,while FR II BL Lacs are possible intermediate stages in the sequence of blazars from FSRQs to FR I BL Lacs with j lower than FR II BL Lacs.It is indicated that there is a disk-jet symbiosis in blazars.
LIU HongTao1 & Chen Liang1,2 1 National Astronomical Observatories/Yunnan Observatory,Chinese Academy of Sciences,Kunming 650011,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.
The relationship between broad line luminosity LBLR and extended radio power PE is investigated.In the log PE-log LBLR diagram,FSRQs populate the region of higher luminosity relative to BL Lacs,and FR II BL Lacs are between FSRQs and FR I BL Lacs.For these blazars,there is a significant correlation between LBLR and PE.The regression line scales as PE ∝ L0B.L87R ± 0.15.The slope of this scaling relation is consistent with that derived from the simple theoretical formulae.Thus,the unification of BL Lacs and FRSQs into a single population finds a statistical basis,and a disk-jet symbiosis in blazars is confirmed.FR II BL Lacs are probably at an intermediate stage in the sequence from FSRQs to BL Lacs with FR I BL Lacs at the end of this sequence.
LIU HongTao & Bai JinMing National Astronomical Observatories/Yunnan Observatory,Chinese Academy of Sciences,Kunming 650011,China
We report the progress on Very Long Baseline Interferometry(VLBI) observations of Gigahertz Peaked Spectrum(GPS) radio sources,and single-dish observations of active galactic nuclei(AGNs).The GPS sources are a kind of young AGNs observable in radio.From our VLBI observations at 1.6 and 5 GHz with the European VLBI Network(EVN) including the Urumqi and Shanghai stations,most GPS sources show compact doubles with sizes less than 1 kiloparsec.We have classified the sources into double-lobes,core-jets,and complex structures according to the spectral indices as well as images.We also estimated the values of the jet viewing angle for the symmetric objects.In addition,we are monitoring a few samples of AGNs with the Urumqi 25-meter radio telescope,in order to find flux variability.We detected rapid flux variability in quasar 1156+295,and relatively slow variability in a few of the others.The origin of the rapid variability is discussed.Moreover,we launched a radio-optical monitoring program called Fermi-AGN in 2009.
We briefly review the proposed relations between the frequencies of twin kilohertz quasi-periodic oscillations(kHz QPOs) and the spin frequencies in neutron star low-mass X-ray binaries(NSLMXBs).To test the validity of the proposed models,we estimate the spin frequencies under these theoretical relations and compare them with the measured ones.It seems that magnetohydrodynamic(MHD) oscillations are more promising to account for the kHz QPOs.
SHI ChangSheng Department of Astronomy,Nanjing University,Nanjing 210093,China
The detection of very high energy γ-ray emission from the Galactic center has been reported by four independent groups. One of these γ-ray sources, the 10 TeV -γ-ray radiation reported by HESS, has been suggested as having a hadronic origin when relativistic protons are injected into and interact with the dense ambient gas. Assuming that such relativistic protons required by the hadronic model come from the tidal disruption of a star by the massive black hole of Sgr A＊, we explore the spectrum of the relativis- tic protons. In the calculations, we investigate cases where different types of stars are tidally disrupted by the black hole of Sgr A＊, and we consider that different diffusion mechanisms are used for the propagation of protons. The initial energy distribution of the injected spectrum of protons is assumed to follow a power-law with an exponential cut-off, and we derive the different indices of the injected spectra for the tidal disruption of different types of stars. For the best fit to the spectrum of photons detected by HESS, the spectral index of the injected relativistic protons is about 2.05 when a red giant is tidally disrupted by the black hole of Sgr A＊ and the diffusion mechanism is the Effective Confinement of Protons.
