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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 {2.,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 {2. of Chinese academy of sciences,beijing 100012.china 1. national astronomical {2. 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 2.0 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 2.0 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

Modeling earthquake indexes derived from the earthquake warning system upon the planet earth

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Science china(Physics,Mechanics & Astronomy) 2010年第12期53卷 2293-2299页

作者： LI Yong national astronomical {2., Chinese academy of sciences, beijing 100012, china 1. national astronomical {2. Chinese Academy of Sciences Beijing 100012 China

By studying the correlation between historical earthquake data and the distributional characteristics of parameters of solid earth tides in the earthquake epicenter, we are able to design a forecasting function of earthquake probability. We put forward a design method for the Earthquake Warning System. The model could theoretically simulate and be used to predict the probability of strong earthquakes that could occur anywhere at any time. In addition, the system could also conveniently obtain global or partial Modeling Earthquake Indexes to finally combine the precise pointing prediction and forecast of partial indexes. The literature quotes global data values, provided by NEIC, of 1544 M ≥ 6.5 earthquakes. It also gives examples of instantaneous earthquake indexes of the whole world and Taiwan Region on 1st January 2.10, UT=0:00 and the average earthquake index near the Taiwan Region. According to the 10-year pointing prediction of strong earthquakes in San Francisco, the literature provides the average earthquake index on 2.th June 2.15 (± 15 days), in its neighborhood.

关键词： earthquake earthquake warning system astrogeodynamics index

2.ASS photometry and age estimation of the globular clusters in the outer halo of M31

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Research in Astronomy and Astrophysics 2012年第2期12卷 115-126页

作者： Jun Ma 1,2. national astronomical {2.,Chinese academy of sciences,beijing 100012.china 2.Key Laboratory of Optical Astronomy,national astronomical {2.,Chinese academy of sciences,beijing 100012.china national astronomical {2. Chinese Academy of Sciences Beijing 100012 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

We present the first photometric results in J, H and Ks from 2.ASS （Two Micron All Sky Survey） imaging of 10 classical globular clusters （GCs） in the far outer regions of M31. Combined with the V and I photometric data from previous literature, we constructed a color-color diagram between J - Ks and V - Ⅰ. By comparing the integrated photometric measurements with evolutionary models, we estimate the ages of these clusters. The results showed that all of these clusters are older than 3 × 109 yr, and among them four are older than 10 Gyr and the other six have intermediate ages between 3 - 8 Gyr. The masses for these outer-halo GCs are from 7.0 × 104 M to 1.02.× 10^6 M. We argued that GC2.and GC3, whose ages, metallicities and distance moduli are almost the same, were accreted from the same satellite galaxy, if they did not form in situ. The statistical results show that the ages and metallicities of these 10 M31 outer-halo GCs do not vary with projected radial position, and a relationship between age and metallicity does not exist.

关键词： galaxies: halos - galaxies: individual (M31) - star clusters: general

Expected Number Counts of Radio Galaxy Clusters

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Chinese Journal of Astronomy and Astrophysics 2002年第2期2卷 106-111页

作者： Wei Zhou national astronomical {2., Chinese academy of sciences, beijing 100012 national astronomical {2. Chinese Academy of Sciences Beijing 100012

Clusters of galaxies may contain radio sources if they still experience successive mergers at present. This has been confirmed by radio observations that about 30% of nearby clusters possess radio halos. We present a theoretical pre- diction of radio cluster counts using a semi-analytic approach which incorporates the empirical correlation between radio power and dynamical mass of clusters, and the cluster mass function described by the Press-Schechter formalism. The total population of radio clusters over the whole sky and their redshift distribution are given.

关键词： cosmology: theory-galaxies: cluster: general-radio sources:extended

Simulation of interplanetary scintillation with SSSF and SSDF mode

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Science china(Physics,Mechanics & Astronomy) 2010年第1期53卷 187-192页

作者： LIU LiJia & PENG Bo national astronomical {2., Chinese academy of sciences, beijing 100012, china 1. national astronomical {2. Chinese Academy of Sciences Beijing 100012 China

The sun has the biggest effect on the Earth in many ways. Observing the solar wind is an important method to study the solar-earth environment. Ground-based interplanetary scintillation observations are an effective method of monitoring solar wind speed, studying the random fluctuations of the interplanetary plasma and the structures of radio sources. Two modes of single-station observations, namely, single station-single frequency (SSSF) and single station dual-frequency (SSDF), are briefly introduced and numerically simulated in this paper. The SSSF mode are easier to carry out and has been widely used. Although the observing system and data processing system of the SSDF mode are more complicated, it can measure the solar wind speed more accurately. A new SSDF system is under construction in Miyun, NAOC (the national astronomical {2., Chinese academy of sciences), with a 50 m telescope, which will serve the Meridian Project, and this paper is devoted to preparing for this new system.

关键词： interplanetary scintillation single station-single frequency single station dual-frequency simulation

Testing the Universality of the TIS Model on Cluster Scales from the X-ray Surface Brightness Profiles

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Chinese Journal of Astronomy and Astrophysics 2001年第1期1卷 29-38页

作者： Yu-Ying Zhang (beijing astronomical Observatory and {2. astronomical observatories, Chinese academy of sciences, beijing 100012) beijing astronomical Observatory and {2. astronomical observatories Chinese Academy of Sciences Beijing 100012

The truncated isothermal sphere (TIS) model has been recently suggested as an alternative for virialized dark halos (Shapiro et al. 1999). Both its profound theoretical motivation and its successful explanations for the galactic rotation curves and the gravitational scaling laws of clusters indicate that the TIS model is a promising candidate among other prevailing models such as the NFW profile and the Burkert profile. This promotes us to re-examine the universality of the TIS model on cluster scales from a different angle. Using an ensemble of X-ray surface brightness profiles of 45 clusters, we test the goodness of fit of the TIS predicted gas distributions to the X-ray data under the assumption of isothermal, hydrostatic equilibrium. Unlike the conventional B model or the NFW/Burkert profile, for which about half of the clusters have the reduced X2.values smaller than 2. the TIS model fails in the fitting of the X-ray surface brightness profiles of clusters in the sense that 38 out of the 45 clusters show X2.> 2. This may constitute a challenge for the universality of the TIS model unless the present analysis is seriously contaminated by other uncertainties including the negligence of non-gravitational heating processes and the unconventional sampling of the X-ray data.

关键词： cosmology: theory -dark matter - galaxies: clusters: general- X-rays: galaxies

A Remark on Using Gravitational Lensing Probability as a Probe of the Central Regions of CDM Halos

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Chinese Journal of Astronomy and Astrophysics 2002年第5期2卷 399-407页

作者： YunLinational astronomical {2., Chinese academy of sciences, beijing 100012 national astronomical {2. Chinese Academy of Sciences Beijing 100012

We calculate the gravitational lensing probabilities by cold dark matter (CDM) halos with different density profiles, and compare them with current observations from the Cosmic Lens All-Sky Survey (CLASS) and the Jodrell-Bank VLA Astrometric Survey (JVAS). We find that the lensing probability is dramatically sensitive to the clumping of the dark matter, or quantitatively, the concentration parameter. We also find that our predicted lensing probabilities in most cases show inconsistency with the observations. It is argued that high lensing probability may not be an effective tool for probing the statistical properties of inner structures of dark matter halos.

关键词： cosmology: dark matter - gravitational lensing - cosmology:theory - galaxies: halos

Infrared Galaxies in the Nearby Universe

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Chinese Journal of Astronomy and Astrophysics 2008年第6期8卷 643-652页

作者： Jian-Ling Wang 1 national astronomical {2.,Chinese academy of sciences,beijing 100012.china 2.Graduate School of Chinese academy of sciences,beijing 100049,china national astronomical {2. Chinese Academy of Sciences Beijing 100012 China Graduate School of Chinese academy of sciences Beijing 100049 China

We used the Sloan Digital Sky Survey （SDSS） Data Release 5 （DR5） to study the morphological properties of 1137 nearby infrared （IR） galaxies, most of which are brighter than 15.9 mag in r-band. This sample was drawn from a cross-correlation of the Infra-Red astronomical Satellite （IRAS） point source catalog redshift survey with DR5 at z ≤ 0.08. Based on this IR galaxy sample, we constructed five volume-limited sub-samples with IR luminosity ranging from 10^9.5 L⊙ to 10^12.⊙. By deriving the IR luminosity functions （LF） for different morphological types, we found that normal spiral galaxies are the dominant population below LIR ~ 8 ~ 10^10 L⊙; while the fraction of barred spiral galaxies increases with increasing IR luminosity and becomes dominant in spiral galaxies beyond LIR ≈ 5 × 10^10L⊙. As the IR luminosity decreases, the IR galaxies become more compact and have lower stellar masses. The analysis also shows that normal spiral galaxies give the dominant contribution to the total comoving IR energy density in the nearby universe, while, in contrast, the contribution from peculiar galaxies is only 39%.

关键词： galaxies evolution galaxies interactions galaxies starburst infrared galaxies galaxies luminosity function

A network flow algorithm to position tiles for LAMOST

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Research in Astronomy and Astrophysics 2009年第11期9卷 1277-1284页

作者： Guang-Wei Li and Gang Zhao national astronomical {2., Chinese academy of sciences, beijing 100012, china national astronomical {2. Chinese Academy of Sciences Beijing 100012 China

We introduce the network flow algorithm used by the Sloan Digital Sky Survey （SDSS） into the sky survey of the Large sky Area Multi-Object fiber Spectroscopic Telescope （LAMOST） to position tiles. Because fibers in LAMOST＇s focal plane are distributed uniformly, we cannot use SDSS＇ method directly. To solve this problem, firstly we divide the sky into many small blocks, and we also assume that all the targets that are in the same block have the same position, which is the center of the block. Secondly, we give a value to limit the number of the targets that the LAMOST focal plane can collect in one square degree so that it cannot collect too many targets in one small block. Thirdly, because the network flow algorithm used in this paper is a bipartite network, we do not use the general solution algorithm that was used by SDSS. Instead, we give our new faster solution method for this special network. Compared with the Convergent Mean Shift Algorithm, the network flow algorithm can decrease observation times with improved mean imaging quality. This algorithm also has a very fast running speed. It can distribute millions of targets in a few minutes using a common personal computer.

关键词： methods data analysis -- methods statistical