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Properties of Broad Band Continuum of Narrow Line Seyfert 1 Galaxies

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chinese Journal of Astronomy and Astrophysics 2002年第6期2卷 501-524页

作者： Hong-Yan Zhou and Ting-Gui WangCenter for Astrophysics, University of Science and Technology of china, Hefei 23.026national astronomical {3., chinese Academic of Science, Beijing 100012 national astronomical observatories Chinese Academic of Science Beijing 100012

We have performed a statistical study of the properties of the broad band continuum of Narrow Line Seyfert 1 galaxies (NLS1s) by collecting ratio, infrared, optical and X-ray continuum data from various databases and compared the results with control samples of Broad Line Seyfert 1 galaxies (BLS1s). We find that the fraction (similar to 6%) of Radio Loud (RL) NLS1s is significantly less than that of BLS1s (similar to 13.), which is caused by the lack of radio-very-loud sources in the former. The rarity of RL NLS1s, especially radio-very-loud ones, is consistent with the scenario of small black hole and high accretion rate for NLS1s. Six new radio loud NLS1s are found and five RL NLS1 candidates are presented. In comparison with the BLS1s, the NLS1s tend to have stronger far infrared emission, cooler infrared colors and redder B - K color, which suggests that NLS1s are hosted by dust-richer nuclei. The NLS1s also show steeper soft X-ray spectrum and large soft X-ray to optical flux ratio, while a significant fraction show flat soft X-ray spectra. At least two factors can account for this, absorption and spectral variability. We also perform a correlation analysis between various broad band data. It is found that most correlations identified for NLS1s are also valid for radio quiet BLS1s: (1) the optical colors are anti-correlated with X-ray spectral index; (2) higher optical, Xray and NIR luminosity objects show bluer optical colors and red H - K color; (3. higher luminosity objects show warmer IRAS color; (4) the radio loudness correlates with B - K and X-ray to optical flux ratio. Radio loud objects behave somewhat differently in a few correlations.

关键词： galaxies : active galaxies : Seyfert radiation : continuum

Evidence of a two-component jet in the afterglow of GRB 070419A

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 265-266页

作者： ZHENG WeiKang1,2 & DENG JinSong1 1 national astronomical observatories,{3. academy of Sciences,Beijing 100012,china 2 Graduate University of {3. academy of Science,Beijing 100049,china 1. national astronomical observatories Chinese Academy of Sciences Beijing 100012 China 2. Graduate University of chinese academy of Science Beijing 100049 China

A two-component jet model is proposed to explain the unusual afterglow of GRB *** the optical light curve,a wide "jet" with an opening angle of >3.-40 degrees is assumed to produce the late shallow decay,while the three early power-law segments must be caused by a narrow jet with an opening angle of-2-4 *** energy injections to both components are *** X-ray emission may come from either the wide jet or the narrow *** the latter is correct,the jets may run into an ISM environment and the temporal index of the late energy injection may be q-0.65.

关键词： gamma-rays:bursts gamma-rays:observations

1RXS J23.953.9+062814: a New SU UMa Dwarf Nova below the Period Minimum

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chinese Journal of Astronomy and Astrophysics 2001年第6期1卷 483-486页

作者： Jian-Yan Wei, Xiao-Jun Jiang, Da-Wei Xu, Ai-Ying Zhou and Jing-Yao Hu national astronomical observatories, {3. academy of Sciences, Beijing 100012 national astronomical observatories Chinese Academy of Sciences Beijing 100012

RXS 123.953.9+062814 was identified as a cataclysmic variable by Wei et al. (1999). Four low-resolution spectra of 1RXS J23.953.9+062814 were obtained with the 2.16-rn telescope of the national astronomical observatories, of which two were at outburst, and two were at quiescence. The system is about 16.8 B and 16.5 V at quiescence, and 12.6 B and 12.6 V at outburst. The quiescent spectra were dominated by double-peaked Balmer emissions, which indicates a hydrogen-rich system with a high-inclination accretion disc. MgH and TiO absorption bands appeared in the quiescent spectrum which implies a companion with a spectral type of early M dwarf. If we take it as a MO dwarf, then the system is located at a distance of 3.0 pc with a proper motion velocity 150 km s-1. The superhump period of 0.0463.1 days was confirmed by our V photometry. The short period and the hydrogen-rich nature reveal that this system is another SU Ursae Majoris-type dwarf nova below the period minimum after V485 Centauri. 1RXS J23.2953.9+062814 is one of the most important systems for studying the evolutionary scenario of cataclysmic variables since it is much brighter than V485 Cen.

关键词： stars: dwarf novae - stars: cataclysmic variables: individual: 1RXS J23.953.9 +062814

A New Catalogue of Fine Structures Superimposed on Solar Microwave Bursts

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chinese Journal of Astronomy and Astrophysics 2004年第2期4卷 176-188页

作者： Qi-Jun Fu, Yi-Hua Yan, Yu-Ying Liu, Min Wang and Shu-Juan Wangnational astronomical observatories, {3. academy of Sciences, Beijing 100012 fuqijun2002@*** national astronomical observatories Chinese Academy of Sciences Beijing 100012

The 2.6-3.8 GHz, 4.5-7.5 GHz, 5.2-7.6 GHz and 0.7-1.5 GHz componentspectrometers of Solar Broadband Radio Spectrometer (SBRS) started routine observations,respectively, in late August 1996, August 1999, August 1999, and June 2000. They just managed tocatch the coming 23.d solar active maximum. Consequently, a large amount of microwave burst datawith high temporal and high spectral resolution and high sensitivity were obtained. A variety offine structures (FS) superimposed on microwave bursts have been found. Some of them are known, suchas microwave type Ⅲ bursts, microwave spike emission, but these were observed with more detail;some are new. Reported for the first time here are microwave type U bursts with similar spectralmorphology to those in decimetric and metric wavelengths, and with outstanding characteristics suchas very short durations (tens to hundreds ms), narrow bandwidths, higher frequency drift rates andhigher degrees of polarization. Type N and type M bursts were also observed. Detailed zebra patternand fiber bursts at the high frequency were found. Drifting pulsation structure (DPS) phenomenaclosely associated with CME are considered to manifest the initial phase of the CME, andquasi-periodic pulsation with periods of tens ms have been recorded. Microwave 'patches', unlikethose reported previously, were observed with very short durations (about 3.0 ms), very high fluxdensities (up to 1000 sfu), very high polarization (about 100% RCP), extremely narrow bandwidths(about 5%), and very high spectral indexes. These cannot be interpreted with the gyrosynchrotronprocess. A superfine structure in the form of microwave FS (ZPS, type U), consisting of microwavemillisecond spike emission (MMS), was also found.

关键词： sun: flares sun: radio radiation instrumentation: spectro-graphs

The relationship of extended radio power and broad emission line luminosity in blazars

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 240-243页

作者： LIU HongTao & Bai JinMing national astronomical observatories/Yunnan Observatory,{3. academy of Sciences,Kunming 650011,china chinese Acad Sci Yunnan Observ Natl Astron Observ Kunming 650011 Peoples R China

The relationship between broad line luminosity LBLR and extended radio power PE is *** 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 *** these blazars,there is a significant correlation between LBLR and *** regression line scales as PE ∝ L0B.L87R ± *** slope of this scaling relation is consistent with that derived from the simple theoretical ***,the unification of BL Lacs and FRSQs into a single population finds a statistical basis,and a disk-jet symbiosis in blazars is *** 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.

关键词： accretion black hole physics BL Laceratae objects:general galaxies:nuclei quasars:general

Calibration of Vector Magnetogram with the Nonlinear Least-squares Fitting Technique

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chinese Journal of Astronomy and Astrophysics 2004年第4期4卷 365-376页

作者： Jiang-TaoSu Hong-QiZhang nationalastronomicalobservatories ChineseAcademyofSciencesBeijing100012

To acquire Stokes profiles from observations of a simple sunspot with the Video Vector Magnetograph at Huairou Solar Observing Station (HSOS), we scanned the FeI λ53.4.19 A line over the wavelength interval from 150mA redward of the line center to 150mA blueward, in steps of 10mA. With the technique of analytic inversion of Stokes profiles via nonlinear least-squares, we present the calibration coefficients for the HSOS vector magnetic magnetogram. We obtained the theoretical calibration error with linear expressions derived from the Unno-Becker equation under weak-field approximation.

关键词： Sun: activity - Sun: magnetic fields - sunspots

An iterative wavefront sensing algorithm for high-contrast imaging systems

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Research in Astronomy and Astrophysics 2011年第2期11卷 198-204页

作者： Jiang-Pei Dou 1,2,De-Qing Ren 1,2,3.and Yong-Tian Zhu 1,2 1 national astronomical observatories/Nanjing Institute of astronomical Optics & Technology,chinese academy of Sciences,Nanjing 210042,china 2 Key Laboratory of astronomical Optics & Technology,Nanjing Institute of astronomical Optics & Technology,chinese academy of Sciences,Nanjing 210042,china 3.Physics & Astronomy Department,California State University Northridge,18111 Nordhoff Street,Northridge,California 913.0-8268,USA national astronomical observatories / Nanjing Institute of astronomical Optics & Technology Chinese Academy of Sciences Nanjing 210042 China Key Laboratory of astronomical Optics & Technology Nanjing Institute of Astronomical Optics & Technology Chinese Academy of Sciences Nanjing 210042 China Physics & Astronomy Department California State University Northridge 18111 Nordhoff Street Northridge California 91330-8268 USA

Wavefront sensing from multiple focal plane images is a promising technique for high-contrast imaging ***,the wavefront error of an optics system can be properly reconstructed only when it is very *** paper presents an iterative optimization algorithm for the direct measurement of large static wavefront errors from only one focal plane *** first measure the intensity of the pupil image to get the pupil function of the system and acquire the aberrated image on the focal plane with a phase error that will be *** we induce a dynamic phase on the tested pupil function and calculate the associated intensity of the reconstructed image on the focal *** algorithm will then try to minimize the intensity difference between the reconstructed image and the aberrated test image in the focal plane,where the induced phase is a variable of the optimization *** simulation shows that the wavefront of an optical system can theoretically be reconstructed with high precision,which indicates that such an iterative algorithm may be an effective way to perform wavefront sensing for high-contrast imaging systems.

关键词： techniques: image processing -- methods: numerical -- planetarysystems

Analysis on the positioning precision of CAPS

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Science china(Physics,Mechanics & Astronomy) 2009年第3期52卷 328-332页

作者： JI YuanFa1,2 & SUN XiYan1,2 1 national astronomical observatories, {3. academy of Sciences, Beijing 100012, china 2 Applied Science and Technology College, Guilin University of Electronic Technology, Guilin 541004, china 1. national astronomical observatories Chinese Academy of Sciences Beijing 100012 China 2. Applied Science and Technology College Guilin University of Electronic Technology Guilin 541004 China

As a newly developed satellite positioning system, the chinese Area Positioning System (CAPS) is a typical direct sequence spread spectrum ranging system like GPS. The positioning precision of such navigation signals depends on many factors, including the pseudo-code rate, the signal to noise ratio, the processing methods for tracking loops and so on. This paper describes the CAPS link budget, the solution approach for CAPS positioning, focusing on the autocorrelation function feature of C/A code signals. The CAPS signal measurement precision is studied by the software approach together with theoretical analysis of the range resolution. Because the conventional Delay Lock Loop (DLL) is vul- nerable to the impact of noise, a narrow correlator and multiple correlators as well as the corresponding discrimination methods of phases are proposed, which improves the robustness of DLL and the code-phase resolution of the measurement. The results show that the improvement of the DLL structure and the discrimination method are the most important way to improve the ranging resolution. Theoretical analysis and experimental results show that a CAPS receiver could reach a 20-m positioning precision by using three satellites with a supported height from an altimeter.

关键词： satellite navigation receiver narrow correlation tracking loop

Birthrates and delay times of Type Ia supernovae

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Science china(Physics,Mechanics & Astronomy) 2010年第3期53卷 586-590页

作者： WANG Bo1,2,3. LIU ZhengWei1,2,3. HAN YunKun1,2,3. LEI ZhenXin1,2,3. LUO YangPing1,2,3.& HAN ZhanWen1,2 1national astronomical observatories/Yunnan Observatory, {3. academy of Sciences, Kunming 650011, china 2Key Laboratory for the Structure and Evolution of Celestial Objects, {3. academy of Sciences, Kunming 650011, china 3.raduate University of {3. academy of Sciences, Beijing 100049, china 1. national astronomical observatories/Yunnan Observatory Chinese Academy of Sciences Kunming 650011 China2. Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming 650011 China3. Graduate University of Chinese Academy of Sciences Beijing 100049 China

Type Ia supernovae (SNe Ia) play an important role in diverse areas of astrophysics, from the chemical evolution of galaxies to observational cosmology. However, the nature of the progenitors of SNe Ia is still unclear. In this paper, according to a detailed binary population synthesis study, we obtained SN Ia birthrates and delay times from different progenitor models, and compared them with observations. We find that the Galactic SN Ia birthrate from the double-degenerate (DD) model is close to those inferred from observations, while the birthrate from the single-degenerate (SD) model accounts for only about 1/2-2/3.of the observations. If a single starburst is assumed, the distribution of the delay times of SNe Ia from the SD model is a weak bimodality, where the WD + He channel contributes to the SNe Ia with delay times shorter than 100 Myr, and the WD + MS and WD + RG channels to those with age longer than 1 Gyr.

关键词： binaries: close stars: evolution supernovae: general white dwarfs