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Multi-epoch X-ray observations of the narrow-line Seyfert 1 galaxy SDSS J160508.87+3.3.21.4 with XMM-Newton

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science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 207-211页

作者： AI YanLi1,2,3.YUAN WeiMin1,2,ZHOU HongYan4,5 & WANG JianGuo1,2,3.1 National astronomical Observatories/Yunnan observatory,Chinese Academy of sciences,Kunming 650011,{3. 2 Key Laboratory for the Structure and Evolution of Celestial Objects,Chinese Academy of sciences,Kunming 650011,{3. 3.Graduate university of the Chinese Academy of sciences,Beijing 100049,{3. 4 Center for Astrophysics,university of science and technology of china,Hefei 23.026,{3. 5 joint institute of Galaxies and cosmology,SHAO and USTC,shanghai 2.0030,{3. National astronomical Observatories/Yunnan observatory Chinese Academy of Sciences Kunming China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming China Graduate university of the Chinese Academy of sciences Beijing China Center for Astrophysics University of Science and Technology of China Hefei China joint institute of Galaxies and cosmology SHAO and USTC Shanghai China

We present results of multi-epoch XMM-Newton observations separated by several years of the narrow-line Seyfert 1(NLS1) galaxy,SDSS J160508.87+*** NLS1 showed X-ray flux variations on timescales of years as well as low amplitude variations on timescales as short as hours,while the X-ray spectral shape remained essentially *** spectrum shows a significant soft X-ray *** model of reflection from an ionized disc,that is dominant in the whole XMM-Newton bandpass,provides the best description of the observed spectra for all the observations,though alternatives such as Compton scattering(T-0.25 keV) cannot be ruled out in a statistical *** the disc reflection model,the observed variations may originate either from the change in the reflection fraction,or from the variability of the intrinsic X-ray luminosity.

关键词： galaxies:active Seyfert X-rays individual

Long-term variation time scales in OJ 287

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Research in Astronomy and Astrophysics 2010年第11期10卷 1100-1108页

作者： Jun-Hui Fan Yi Liu Bo-Chun Qian Jun Tao Zhi-Qiang Shen Jiang-Shui Zhang Yong Huang Jin Wang Center for Astrophysics Guangzhou University Guangzhou 510400 China Astronomy science and technology Research Laboratory. of Department of Education of Guangdong Province Guangzhou 510006 China shanghai astronomical observatory Chinese Academy of Sciences Shanghai 200030 China joint institute for galaxy and {3. ShAO and USTC Chinese Academy of Sciences China

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.

关键词： galaxies active -- galaxies: general-- methods: data analysis -- galax- ies individual (OJ 287)

Bending of Jets in the QSO NRAO 53.

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Chinese Journal of Astronomy and Astrophysics 2008年第2期8卷 179-194页

作者： Xiao-Yu Hong Chuan-Hao Sun Jun-Hui Zhao Dong-Rong Jiang Zhi-Qiang Shen Tao An Wei-Hua Wang Jun Yang shanghai astronomical observatory Chinese Academy of Sciences Shanghai 200030 Graduate university of Chinese Academy of sciences Beijing 100049 Harvard-Smithsonlan Center for Astroplaysics 60 Garden street MS 72 Cambridge MA02138 joint institute for galaxy and {3.

We present radio images of NRAO 53. on scales ranging from pc to kpc. The observations include the EVN at 5 GHz, the VLBA at 1.6, 8.6 and 15 GHz, the MERLIN at 1.6 and 5 GHz, and the VLA at 5, 8.4, 15, 22, and 43.GHz. The VLBI images show a core-jet structure with an oscillating trajectory on a scale of about 3. mas north of the strongest compact component （core）. Superluminal motions are detected in five of the jet components with apparent velocities in the range of 13.6 to 25.2c. A new component is detected at 15 GHz with the VLBA observations, which appears to be associated with the outburst in 2002. Significant polarized emission is detected around the core with the VLBA observations at 15 GHz. Rapid variations of the polarization intensity and angle are found between the epochs in 2002 and 2004. On the kpc-scale, a distant component （labelled as WL） located 11 arcsec west （PA=-86°） of the core is detected beyond the core-jet structure which extended to several hundreds of mas in the north-west direction （-50°）. A significant emission between the core-jet structure and the WL is revealed. A clump of diffuse emission （labelled EL, 12 arcsec long） at PA 70° to the core, is also detected in the VLA observations, suggesting the presence of double lobes in the source. The core component shows a fiat spectrum, while the distant components WL and EL have steep spectra. The steep spectra of the distant components and the detection of the arched emission suggest that the distant components are lobes or hot-spots powered by the core of NRAO 53.. The morphologies from pc- to kpcscales and the bending of jets are investigated. The observed radio morphology from pc to kcp appears to favor the model in which precession or wobbling of the nuclear disk drives the helical motion of the radio plasma and produces the S-shaped structure on kpc scale.

关键词： galaxies: nuclei -- galaxies: jets -- quasars: individual: NRAO 53.