National Astronomical Observatories

output

19932026

researchers with a paper here

Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.

collaborating institutions

Showing 1998 · astro-phShow all

16 papers · 2 filters

astro-ph1998

Large-scale structures in the distribution of X-ray selected AGN

D. Engels, F. Tesch, C. Ledoux +5

We are searching for large-scale structures in the distribution of AGN discovered by the ROSAT All-Sky Survey. The RASS detected > 60000 X-ray objects, of which approximately 35% a…

astro-ph1998★ 1 cited

Ultraluminous IRAS galaxy 10026+4347

X. -Y. Xia, Shude Mao, H. Wu +4

We study optical and X-ray properties of the ultraluminous IRAS galaxy 10026+4347. This galaxy is a narrow-line QSO with very strong FeII emission. Three optical spectra were taken…

astro-ph1998★ 20 cited

New Wolf-Rayet Galaxies with Detection of WC Stars

J. H. Huang, Q. S. Gu, L. Ji +3

We report the discovery of two new Wolf-Rayet (WR) galaxies: Mrk~1039, and F08208 $+$ 2816. Two broad WR bumps at 5808Å~ and 4650Å~ indicate the presence of WCE and WNL star populati…

astro-ph1998★ 90 cited

Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XV. Long-Term Optical Monitoring of NGC 5548

B. M. Peterson, A. J. Barth, P. Berlind +34

We present the results of three years of ground-based observations of the Seyfert 1 galaxy NGC 5548, which combined with previously reported data, yield optical continuum and broad…

astro-ph1998★ 2 cited

Updating the $σ$ - $T$ relationship for galaxy clusters

Xiang-Ping Wu, Li-Zhi Fang, Wen Xu

The relationship between the X-ray determined temperature $T$ of the intracluster gas and the optical measured velocity dispersion $σ$ of the cluster galaxies is often believed to…

astro-ph1998

Baryon Fractions and Cluster Mass Estimates

Xiang-Ping Wu

I report the current status on the determinations of the baryon fractions and dynamical/lensing masses of galaxy clusters as well as the $σ$ - $T$ relationship, making use of all t…

astro-ph1998★ 72 cited

A comparison of different cluster mass estimates: consistency or discrepancy ?

Xiang-Ping Wu, Tzihong Chiueh, Li-Zhi Fang +1

Rich and massive clusters of galaxies at intermediate redshift are capable of magnifying and distorting the images of background galaxies. A comparison of different mass estimators…

astro-ph1998★ 100 cited

Circular polarization in pulsar integrated profiles

J. L. Han, R. N. Manchester, R. X. Xu +1

We present a systematic study of the circular polarization in pulsar integrated profiles, based on published polarization data. For core components, we find no significant correlat…

astro-ph1998★ 139 cited

Ring structure and warp of NGC5907 -- Interaction with dwarf galaxies

Zhaohui Shang, Zhongyuan Zheng, Elias Brinks +22

The edge-on, nearby spiral galaxy NGC5907 has long been used as the prototype of a ``non-interacting'' warped galaxy. We report here the discovery of two interactions with companio…

astro-ph1998★ 14 cited

Scale Invariance of Rich Cluster Abundance: A Possible Test for Models of Structure Formation

Wen Xu, Li-Zhi Fang, Xiang-Ping Wu

We investigate the dependence of cluster abundance $n (> M, r_{c l})$ , i.e., the number density of clusters with mass larger than $M$ within radius $r_{c l}$ , on scale parameter $r_{cl}…

astro-ph1998★ 11 cited

Detecting Scale-Dependence of Bias from APM-BGC Galaxies

Li-Zhi Fang, Zu-Gang Deng, Xiao-Yang Xia

We present an investigation of the scale-dependence of bias described by the linear model: $(δ ρ (x) / ρ ˉ)_{g} = b (δ ρ (x) / ρ ˉ)_{m}$ , $b$ being the bias parameter, and $ρ({\b…

astro-ph1998★ 10 cited

New clues to the magnetic field structure of M31

J. L. Han, R. Beck, E. M. Berkhuijsen

We observed 21 polarized background radio sources in the field of M31 at 1.365 GHz and 1.652 GHz, and determined their rotation measures (RMs). The RM data show that the regular ma…

astro-ph1998★ 1 cited

Generalized thermal instability criterion of black hole accretion disks

Xue-Bing Wu

The conventional thermal instability criterion can not be applied to the advection-dominated accretion disks around black holes where the radiative cooling is insufficient to balan…

astro-ph1998★ 6 cited

Questions on pure luminosity evolution for ellipticals

Ping He, Yuan-Zhong Zhang

The explanation for the existence of an excess population of faint blue galaxies (FBGs) has been a mystery for nearly two decades, and remains one of the grand astronomical issues…

astro-ph1998★ 114 cited

Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XII. Ground-Based Monitoring of 3C 390.3

M. Dietrich, B. M. Peterson, P. Albrecht

Results of a ground-based optical monitoring campaign on 3C 390.3 in 1994-95 are presented. The broad-band fluxes (B, V, R, and I), the spectrophotometric optical continuum flux F(…