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Relativist ic Corrections to the Thermal Sunyaev-Zel'dovich Power Spectrum

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chinese Journal of Astronomy and Astrophysics 2003年第5期3卷 410-414页

作者： Hai-Ning LiNational astronomical observatories, chinese academy of sciences, beijing 100012 lhnDepartment of Astronomy, beijing Normal University, beijing 100875 National astronomical observatories CAS NAOC Beijing 100012 China []Department of Astronomy Beijing Normal University Beijing 100875

We present a quantitative estimate of the relativistic corrections to thethermal SZ power spectrum produced by the energetic electrons in massive clusters. The correctionsare well within 10% for current experiments with working frequencies below ν 350 GHz. Moreover, the corrections appear to be slightlysmaller at higher l or smaller angular scales. We conclude that there is no need to include therelativistic corrections in the theoretical study of the SZ power spectrum especially at lowfrequencies unless the SZ power spectrum is used for precision cosmology.

关键词： cosmic microwave background cosmology: theory galaxies: clusters: general

Molecular Gas and Dust in the Massive Star Forming Region S 233 IR

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chinese Journal of Astronomy and Astrophysics 2004年第5期4卷 440-454页

作者： Rui-Qing Mao and Qin Zeng1 Purple Mountain Observatory, chinese academy of sciences, Nanjing 210008 2 National astronomical observatories, chinese academy of sciences, beijing 100012 National astronomical observatories CAS NAOC Beijing 100012 China

The massive star forming region S 233 IR is observed in the molecular lines CO J = 2–1, 3–2, NH3 (1,1), (2,2) and the 870 um dust continuum. Four submillimeter continuum sources, labelled SMM 1–4, are revealed in the 870 um dust emission. The main core, SMM1, is found to be associated with a deeply embedded near infrared cluster in the northeast; while the weaker source SMM2 coincides with a more evolved cluster in the southwest. The best fit spectral energy distribution of SMM1 gives an emissivity of β = 1.6, and temperatures of 32 K and 92 K for the cold- and hot-dust components. An SMM1 core mass of 246 M☉, and a total mass of 445 M☉ are estimated from the 870 um dust continuum emission. SMM1 is found to have a temperature gradient decreasing from inside out, indicative of the presence of interior heating sources. The total outflow gas mass as traced by the CO J = 3–2 emission is estimated to be 35 M☉. Low velocity outflows are also found in the NH3 (1,1) emission. The non-thermal dominant NH3 line width as well as the substantial core mass suggest that the SMM1 core is a ``turbulent, massive dense core', in the process of forming a group or a cluster of stars. The much higher star formation efficiency found in the southwest cluster supports the suggestion that this cluster is more evolved than the northeast one. Large near infrared photometric variations found in the source PCS-IR93, a previously found highly polarized nebulosity, indicate an underlying star showing the FU Orionis type of behavior.

关键词： ISM: jets and outflows ISM: molecules ISM: dust, extinction stars:formation ISM: individual

A Note on the Mixing Length Theory and Massive Star Evolution

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chinese Journal of Astronomy and Astrophysics 2001年第1期1卷 50-56页

作者： Li-Cai Deng and Da-Run Xiong ( beijing astronomical Observatory, chinese academy of sciences, beijing 100012 Purple Mountain Observatory, chinese academy of sciences, Nanjing210008 National astronomical observatories, chinese academy of sciences, Beij CAS-Peking University Joint beijing Astrophysical Center Beijing 100871

In this paper, we investigate the problem of supersonic convection caused by the application of the usual Mixing Length Theory (MLT), and give a modification to the original expression of the MLT. In the case of the usual MLT, a zone of supersonic convection exists when the stellar model goes into yellow-red supergiant phase. When the modification is applied, the models of late type supergiants possess shallower convective envelopes for a given temperature compared with the normal formalism of the MLT. Therefore the stellar models made with our new formalism move to lower effective temperature by 100-400 K depending on the luminosity of the star. Such a modification does not affect the convective envelope structure of lower luminosity late type stars, as both expressions of the MLT give the same result. In these stars.

关键词： convection - stars: supergiants - stars: massive stars - stars: evolution

Observational Accuracy of Sunrise and Sunset Times in the Sixth Century China

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chinese Journal of Astronomy and Astrophysics 2006年第5期6卷 629-634页

作者： Yong Li National astronomical observatories Chinese Academy of Sciences Beijing 100012

The Daye Calendar was compiled in AD 597 in the Sui Dynasty. We investigate the records of sunrise and sunset times on the 24 solar-term days in the calendar. By converting the ancient chinese time units, Chen, Ke and Fen to hour, minute and second, and carrying out a comparison between the ancient records and values computed with modem astronomical theory, we find that the accuracy of solar measurements in the Sui period is remarkably high： for sunrise times, the average absolute deviation is 3.63 min （this value can be further reduced to 3.03 min when erroneous data are excluded）, and for sunset times it is 3.48 min. We also find that the observed sunrise and sunset times are strictly symmetrically distributed with respect to both the Winter Solstice and the Summer Solstice, with their deviations showing a similar symmetrical distribution as well. We give a discussion on the date of observation, the feature of the data, and possible reasons of the deviation.

关键词： history of astronomy -- astrometry -- solar-terrestrial relations -- methods statistical

Pulsar observations in China

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chinese Science Bulletin 2002年第4期47卷 265-266页

作者： KANG LianshengNational astronomical observatories, chinese academy of sciences, beijing 100012, China National astronomical observatories Chinese Academy of Sciences Beijing China

The development history and achievement of pulsar observation in China were introduced. The history is very short, only ten years. The cooperation program about pulsar timing observation at 18 cm using a 25-m radio tele-scope of UAO between China, Australia and Great Britain has been carried out since 1997. Some scientific results such as glitch, model changing, interstellar scintillation and the spectra of pulsar have been obtained. The plans of develop-ment of the pulsar observation were also introduced using chinese radio telescopes.

关键词： pulsar observation.

A Possible Origin of 6.7 GHz Linear Methanol Maser Sources

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chinese Journal of Astronomy and Astrophysics 2001年第5期1卷 389-394页

作者： Ye Xu (Shanghai astronomical Observatory, chinese academy of sciences, Shanghai 200030) (Urumqi astronomical Observatory, chinese academy of sciences, Urumqi 830011) (National astronomical observatories, chinese academy of sciences, beijing 100012) E-mail Shanghai astronomical Observatory Chinese Academy of Sciences Shanghai 200030 []Urumqi Astronomical Observatory Chinese Academy of Sciences Urumqi 830011 []National Astronomical Observatories Chinese Academy of Sciences Beijing 100012

We present a model which explains the observed multi-linear spatial structures with different velocity gradients of the 50-61A+ methanol line at 6.7 GHz. We consider this and other hypotheses and conclude that the met... 详细信息

关键词： masers - stars: circumstellar matter - stars: formation

Comparisons of Infrared Colors and Emission-line Intensities between Two types of Seyfert 2 Galaxies

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chinese Journal of Astronomy and Astrophysics 2002年第5期2卷 408-418页

作者： Lin-Peng Cheng, Yong-Heng Zhao and Jian-Yan WeiNational astronomical observatories, chinese academy of sciences, beijing 100012 National astronomical observatories CAS NAOC Beijing China

We study the relation between the infrared colors, [OIII] emission lines, gaseous absorbing column density (NH),and the detectability of the polarized (hidden) broad-line region (HBLR) in a large sample of 75 Seyfert 2 galaxies (Sy2s). From the indicators of star-formation activity, f60/f100 and LFIR/LB, we find some evidence that the Sy2s without HBLR show higher star-formation activities than those with HBLR, in agreement with previous prediction. Also, we confirm that the HBLR Sy2s tend to have a larger luminosity ratio of the core to the host galaxy, suggesting that the HBLR Sy2s display more powerful AGN activity. However, the level of obscuration found in previous papers is nearly indistinguishable between the two types of Sy2s. The results support the statement that the non-HBLR Sy2s, with a weaker core component and a stronger star-formation activity component, are intrinsically different from the HBLR Sy2s, which are Sy1 systems with a hidden powerful AGN core and a low star-formation activity. The indications are that the non-HBLR Sy2s might be at an earlier evolutionary phase than the HBLR Sy2s.

关键词： galaxies: active - galaxies: Seyfert - polarization - star formation

Thermal analysis of the baffle structure of the Solar Space Telescope

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Science China(Physics,Mechanics & Astronomy) 2010年第9期53卷 1755-1764页

作者： LI Rong1,2,3 & WANG Sen1,3 1 National astronomical observatories,chinese academy of sciences,beijing 100012,China 2 Graduate University of chinese academy of sciences,beijing 100049,China 3 Key Laboratory of Solar Activity,National astronomical observatories of chinese academy of sciences,beijing 100012,China 1. National astronomical observatories Chinese Academy of Sciences Beijing 100012 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Key Laboratory of Solar Activity National Astronomical Observatories of Chinese Academy of Sciences Beijing 100012 China

The SST(Space Solar Telescope) is an astronomical telescope with a primary mirror of 1 m in *** observes the sun with a small view field to ensure that its high spatial resolution imaging has 0.1″-0.15″ and high SNR(signal to noise ratio).Surrounding the small view field is still the sun,which is an intense source of both heat and stray *** baffles(the main baffle,the aperture,and the outer baffle),which are used to eliminate the stray light,will change the thermal flux in the SST and will weaken the effect of the thermal control *** this study,the compatibility analysis of the thermal effect of baffle structures in SST is *** GCF(Geometry Composing Function) and BRDF(Bidirectional Reflectance Distribution Function),which are two inherent related parameters in the compatibility analysis,are *** objective and method of the compatibility analysis are *** the thermal analysis software,the temperature fields are calculated for different lengths of the main baffle,different radii of apertures,different lengths of the outer baffle with a 3' tilt angle and 16' tilt angle,and different tilt angles of the outer baffle with a 200 mm length.A series of configurations and sizes of the baffles are studied with the goals of both thermal control and elimination of stray *** design of the baffle structure of SST is achieved:the main baffle of length 4100 mm,the internal shield of radius 494 mm,the outer baffle of length 200 mm,and the outer baffle of tilt angle 3' are successfully *** paper presents the relationship between the thermal control design and stray light elimination plan in the *** aims of the optimal design of the baffle structure of SST are *** thoughts and methods of the optimal analysis are also useful for similar optical telescopes designed for solar observation.

关键词： baffle the main baffle the outer baffle GCF BRDF

The Variability of Hardness Ratio 1 observed by ROSAT:Narrow-Line Seyfert 1 Galaxies versus Broad-Line Seyfert 1 Galaxies

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chinese Journal of Astronomy and Astrophysics 2002年第3期2卷 207-215页

作者： Lin-Peng Cheng , Jian-Yan Wei and Yong-Heng ZhaoNational astronomical observatories, chinese academy of sciences, beijing 100012 National astronomical observatories Chinese Academy of Sciences Beijing 100012

We examined the correlation between the ROSAT Hardness Ratio 1 and Count Rates eight Narrow-line Seyfert 1 Galaxies (NLSls) and 14 Broad-line Seyfertl Galaxies (BLSls). We found that six of the NLSls show a positive HR1-CTs correlation, and seven of the BLSls, a negative correlation. The other two NLSls and seven BLSls do not show any clear HR1-CTs correlation. Thus, the spectral behavior is statistically different for the NLSls and BLSls. The different behaviors can possibly be interpreted in terms of a stable 'soft excess' that is strong in NLSls and weak in BLSls, plus a power law component, common to both, which softens with increasing flux.

关键词： galaxies: Seyfert - galaxies: active - X-ray: galaxies