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Temporal variation of hemispheric solar rotation

Research in Astronomy and Astrophysics 2012年第2期12卷 187-200页

作者： Jing-Lan Xie 1,2.Xiang-jun Shi 1,2.and Jing-Chen Xu 1,2. national {2. Observatories /yunnan observatory,chinese academy of sciences,kunming 650011,china 2.Graduate University of chinese academy of sciences,Beijing 100049,china national astronomical Observatories/ {2. observatory Chinese Academy of Sciences Kunming 650011 China Graduate University of chinese academy of sciences Beijing 100049 China

The daily sunspot numbers of the whole disk as well as the northern and southern hemispheres from 1945 January 1 to 2.10 December 31 are used to investi- gate the temporal variation of rotational cycle length through the continuous wavelet transformation analysis method. Auto-correlation function analysis of daily hemi- spheric sunspot numbers shows that the southern hemisphere rotates faster than the northern hemisphere. The results obtained from the wavelet transformation analysis are that no direct relationship exists between the variation trend of the rotational cy- cle length and the solar activity in the two hemispheres and that the rotational cycle length of both hemispheres has no significant period appearing at 11 yr, but has a sig- nificant period of about 7.6 yr. Analysis concerning the solar cycle dependence of the rotational cycle length shows that acceleration seems to appear before the minimum time of solar activity in the whole disk and the northern hemisphere, respectively. Furthermore, the cross-correlation study indicates that the rotational cycle length of the two hemispheres has different phases, and that the rotational cycle length of the whole disk as well as the northern and southern hemispheres, also has phase shifts with corresponding solar activity. In addition, the temporal variation of the north-south （N- S） asymmetry of the rotational cycle length is also studied. This displays the same variation trend as the N-S asymmetry of solar activity in a solar cycle, as well as in the considered time interval, and has two significant periods of 7.7 and 17.5 yr. Moreover, the rotational cycle length and the N-S asymmetry of solar activity are highly corre- lated. It is inferred that the northern hemisphere should rotate faster at the beginning of solar cycle 2..

关键词： Sun: activity - Sun: rotation - Sun: sunspot

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A puzzle of the radio-quiet quasar PG 1407+2.5:Are optical and X-ray emissions produced from a relativistic jet?

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Science china(Physics,Mechanics & Astronomy) 2011年第1期54卷 183-186页

作者： CHEN liang 1,2.3 & BAI JinMing 1,2.1 {2. astronomical Observatories/yunnan observatory,chinese academy of sciences,kunming 650011,china 2.key Laboratory for the Structure and Evolution of Celestial Objects,chinese academy of sciences,kunming 650011,china 3 Graduate University of chinese academy of sciences,Beijing 100049,china national astronomical Observatories/{2. 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 chinese academy of sciences Beijing China

PG 1407+2.5 is a radio quiet quasar that has a relativistic *** this report,we show some peculiar properties of its optical and X-ray emissions,which indicate possible non-thermal origins produced from the *** use a simple synchrotron + synchrotron self Compton (SSC) model to fit the emissions with different ratios of energy densities between the magnetic field and electrons (η≡U B/U e),which predicts a different γ-ray *** First LAT AGN Catalog (1LAC) did not include PG 1407+2.5,which indicates an upper limit of γ-ray *** upper limit constrains the ratio to be unreasonably large (η≥10 4-5).This inversely indicates that the optical and X-ray emissions may not be produced from the beaming *** discuss the physical implications of these results.

关键词： active galactic nuclei jet non-thermal emission PG 1407+2.5

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The Chemical Classification of the AGB Star IRAS 17515-2.07

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chinese Journal of Astronomy and Astrophysics 2003年第6期3卷 551-554页

作者： Pei-Sheng Chen and Pin Zhang1national astronomical Observatories, {2. observatory, chinese academy of sciences, kunming 650011 2.osmic Ray Institute, {2. University, kunming 650091 national astronomical Observatories Yunnan Observatory Chinese Academy of Sciences Kunming 650011 Cosmic Ray Institute Yunnan University Kunming 650091

The chemical classification of IRAS 17515-2.07 has been debated for a longtime. Up to now there are two contenders, oxygen-rich or carbon-rich. We believe that IRAS17515-2.07 is an oxygen-rich source: because (ⅰ) it shows the silicate self-absorbed emission; (ⅱ)in the near infrared-IRAS diagram it is located in the oxygen-rich object region and (ⅲ)particularly, it has detected SiO maser emission.

关键词： stars: AGB stars: chemical classification stars: maser infrared: stars

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Observational Features of Large-Scale Structures as Revealed by the Catastrophe Model of Solar Eruptions

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chinese Journal of Astronomy and Astrophysics 2007年第4期7卷 457-476页

作者： jun lin {2. astronomical Observatories/yunnan observatory, chinese academy of sciences, kunming 650011 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02.38, USA national astronomical Observatories / {2. observatory Chinese Academy of Sciences Kunming 650011 Harvard-Smithsonian Center for Astrophysics 60 Garden Street Cambridge MA 02138 USA

Large-scale magnetic structures are the main carrier of major eruptions in the solar atmosphere. These structures are rooted in the photosphere and are driven by the unceasing motion of the photospheric material through a series of equilibrium configurations. The motion brings energy into the coronal magnetic field until the system ceases to be in equilibrium. The catastrophe theory for solar eruptions indicates that loss of mechanical equilibrium constitutes the main trigger mechanism of major eruptions, usually shown up as solar flares, eruptive prominences, and coronal mass ejections （CMEs）. Magnetic reconnection which takes place at the very beginning of the eruption as a result of plasma instabilities/turbulence inside the current sheet, converts magnetic energy into heating and kinetic energy that are responsible for solar flares, and for accelerating both plasma ejecta （flows and CMEs） and energetic particles. Various manifestations are thus related to one another, and the physics behind these relationships is catastrophe and magnetic reconnection. This work reports on recent progress in both theoretical research and observations on eruptive phenomena showing the above manifestations. We start by displaying the properties of large-scale structures in the corona and the related magnetic fields prior to an eruption, and show various morphological features of the disrupting magnetic fields. Then, in the framework of the catastrophe theory, we look into the physics behind those features investigated in a succession of previous works, and discuss the approaches they used.

关键词： Sun: large-scale magnetic structures - Sun: eruptive processes - Sun: theory and observations - magnetic reconnection and current sheets

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High-energy radiation from old pulsars

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 135-138页

作者： JIANG Zejun1,2.& ZHANG li{2. yunnan astronomical observatory,national astronomical Observatories,chinese academy of sciences,kunming 650011,china 2.Department of Physics,yunnan University,{12. 650091,china yunnan astronomical {2. National Astronomical Observatories Chinese Academy of Sciences Kunming China Department of Physics Yunnan University Kunming China

In this paper,we study nonthermal high energy radiation from old rotation-powered pulsars with ages greater than 106 yr based on the revised outer gap *** this model,the inclination angle and geometry of the magnetic field have been taken into account,and the fractional size f of the outer gap is determined by the electron/positron pair production *** cascade process caused by the back-flowing particles moving from the outer gap to the star will produce the observed nonthermal X-ray emission,and the relativistic particles accelerated in the outer gap will produce gamma-rays via curvature *** nine old pulsars which have been detected to have nonthermal X-rays,we first use the observed nonthermal X-ray emission to estimate reasonable inclination angles,and then estimate their gamma-ray *** also study the possibilities of gamma-ray emissions from other old rotation-powered *** compare our predicted gamma-ray flux with the sensitivities of AGILE and Fermi.

关键词： superbubble HII region cluster PAH dust

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Stochastic Particle Acceleration in Blazar Jets

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chinese Journal of Astronomy and Astrophysics 2002年第1期2卷 1-7页

作者： Jian-Cheng Wang yunnan observatory Chinse {2. of sciences, kunming 650011 national astronomical Observatories, chinese academy of sciences, Beijing 100012.United Laboratory of Optical Astronomy chinese academy of sciences Extragalactic astronomy Recei yunnan observatory Chinese Academy of Sciences Kunming 650011 national astronomical Observatories Chinese Academy of Sciences Beijing 100012 United Laboratory of Optical Astronomy Chinese Academy of Sciences

The bulk kinetic energy of jets can be dissipated via generating tur- bulen plasma waves. We examine stochastic particle acceleration in blazar jets to explain the emissions of all blazars. We show that acceleration of electrons by plasma turbulence wavs with a spectrum W(k) ~ k^(-4/3) produces a nonthermal population of relativistic electrons whose peak frequency of synchrotron emission can fit the observational trends in the spectral energy distribution of all blazars. The plasma nonlinear processes responsible for the formation of turbulent spectrum are investigated. Increases in the ioteraction time of turbulent waves can produce a fiatter spectrum leading to efficient particle acceleration.

关键词： acceleration of paxticles - blazars: theory - plasma: turbulence - radiation mechanism: nonthermal

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A study of a sequence of blazars from FSRQs to BL Lac objects

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 231-234页

作者： liU HongTao1 & Chen liang1,{2. national astronomical Observatories/yunnan observatory,chinese academy of sciences,kunming 650011,china 2.Graduate University of the chinese academy of sciences,Beijing 100049,china national astronomical Observatories/{2. observatory Chinese Academy of Sciences Kunming China Graduate University of the chinese academy of sciences Beijing China

There are significant correlations between the broad line region luminosity LBLR,the quantity Δmax(maximum of Δ≡log[(Fν)cm/(Fν)mm]) and redshift *** are strong correlations between the extended radio luminosity PE,LBLR and Δ*** 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 *** is indicated that there is a disk-jet symbiosis in blazars.

关键词： black hole physics galaxies:active galaxies:evolution galaxies:nuclei quasars:general

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A statistical study of the relation between soft X-ray excess and accretion disk

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 102-105页

作者： liU JieYing1,2.3 & QIAO Erlin1,{2. national astronomical Observatories/yunnan observatory,chinese academy of Science,kunming 650011,china 2.key Laboratory for the Structure and Evolution of Celestial Objects,{12.,kunming 650011,china 3 Graduate University of {12.,Beijing 100049,china national astronomical Observatories/{2. observatory Chinese Academy of Science Kunming China key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of Sciences Kunming China Graduate University of chinese academy of sciences Beijing China

To study the origin of the soft X-ray excess,we compile a sample of 94 unobscured,radio-quiet QSOs and Seyfert galaxies with available data from GALEX and *** find that 50 sources show strong soft X-ray excess and the other 44 show weak/no soft X-ray *** analyses of the data indicate that the difference in soft X-rays is mainly but not only resulting from different accretion rates(in units of Eddington rate).The statistical study of the sources with soft X-ray excess shows that the strength of soft X-ray excess weakly and positively correlates with the Eddington ratio and increases with the increase of the strength of UV radiations relative to the *** that the UV emissions are from the thin disk,the correlations imply that the origin of soft X-ray excess is associated with the thin disk,either by means of Comptonization of the disk photons or in some other ways.

关键词： accretion:accretion disks ultraviolet:galaxies X-rays:galaxies

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Projection Effects on Physical Parameters Obtained from Solar Vector Magnetograms

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chinese Journal of Astronomy and Astrophysics 2002年第2期2卷 174-182页

作者： Hui li Purple Mountain observatory, {2., Nanjing 2.0008 national astronomical Observatories, {2., Beijing 100012 Purple Mountain observatory Chinese Academy of Sciences Nanjing 210008 national astronomical Observatories Chinese Academy of Sciences Beijing 100012

Projection effects in Huairou solar vector magnetograms are corrected by transferring or mapping the observed vector magnetogram in the image plane to the heliographic plane (planar correction) and to the heliospheric coordinate system (spherical correction). The magnetograms after the correction are considerably dif- ferent. The planar correction and the spherical correction lead to slightly different magnetic configurations, especially when the active region involved is far from the disk center. We also discuss the effects of the corrections on magnetic activity pa- rameters, such as magnetic shear, current helicity, etc. It is shown that the neutral line is obviously distorted after the mapping. The mapping generally decreases the average shear angle on the neutral line by several degrees when the active region is in the eastern hemisphere, and increases it when in the western hemisphere. In most of the cases studied, the correction reduces the current helicity imbalance, and sometimes even changes its sign. It is found that the current helicity imbalance may change its sign in its evolution when there are apparent fluxes emerging from the lower photosphere. The corrections increase the noise level of Bz greatly, and decrease the noise level of B~ slightly. The accuracy of the magnetic field measure- ment at Huairou is estimated to be better than 2. G and 150 G for the longitudinal and the transverse component, respectively.

关键词： Sun: magnetic fields ─Sun: activity ─Sun: photosphere

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The periodicity of 3C 2.3's radio light curve at 15 GHz found by the wavelet method

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Science china(Physics,Mechanics & Astronomy) 2010年第S1期53卷 252-255页

作者： ZHANG HaoJing1,2.ZHAO Gang1,ZHANG Xiong3 & BAI JinMing4 1 national astronomical Observatories,{2.,Beijing 100012.china 2.Graduate University of {2.,Beijing 100049,china 3 Department of Physics,yunnan Normal Univeristy,kunming 650092.china 4 national astronomical Observatories/yunnan {12.,{2.,kunming 650011,china national astronomical Observatories Chinese Academy of Sciences Beijing China Graduate University of chinese academy of sciences Beijing China Department of Physics Yunnan Normal Univeristy Kunming China national astronomical Observatories/ {2. observatory Chinese Academy of Sciences Kunming China

We analyze the radio light curve of 3C 2.3 at 15 GHz from 1963 to 2.06 taken from the database of the literature,and find evidence of quasi-periodic *** the wavelet analysis method to analyze these data,our results indicate that:(1) There is one main outburst period of P1=8.1±0.1 year in 3C *** period is in a good agreement with Ozernoi's analysis in optical bands.(2. Based on the possible periods,we expect the next burst in 2.14 October.

关键词： quasar object individual(3C 2.3) radio band’s periodicity analysis wavelet method

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