National Astronomical Observatories

      Chinese Academy of Sciences

      A20 Datun Road, Chaoyang

      Beijing 100012

      P.R.China

      Email: xuelei@bao.ac.cn

      Fax：86-10-64850103

      Title of talk: Constrain the dark matter property with cosmic ionization history

      Abstract: The cosmic ionization history provides a useful tool to constrain the decay and annihilations of dark matter particles. Even a small fraction of dark matter particles decayed or annihilated during the cosmic dark age can provide sufficient energy to affect the ionization state of the baryonic gas. The ionization history of the Universe can be probed by CMB observations. Using current CMB data, we obtain constraint on the decay and annihilation rate of dark matter particles.

2.  Chu, Yao-Quan  (褚耀泉)

      Center for Astrophysics

      University of Science and Technology of China

      96 Jinzai Lu

      Hefei, Anhui 230026

      P.R.China

      Email: yqchu@ustc.edu.cn

      Fax: 86-551-3631760

     Title of talk: The Scientific Prospect and Project Progress of the LAMOST

     Abstract: focal length of 20-meter and a field of view of 5-degree. Using active optics technique to control its reflecting corrector makes LAMOST a unique astronomical instrument in combining a large aperture with a wide field of view. The available large focal plane of 1.75-meter in diameter may accommodate up to 4000 fibers, by which the collected light of distant and faint celestial objects is fed into the spectrographs, promising a very high spectrum acquiring rate of several ten-thousands of spectra per night. The telescope will be located at the Xinglong Station of Beijing Astronomical Observatory, Chinese Academy of Sciences, as a national facility open to the whole astronomical community. The spectroscopic survey carried out by LAMOST of tens of millions of galaxies and others will make substantial contribution to the study of extra-galactic astrophysics and cosmology, such as galaxies, quasars and the large-scale structure of the universe. Its spectroscopic survey of large number of stars will make substantial contribution to the study of stellar astrophysics and the structure and evolution of The Galaxy. Its spectroscopic survey combining with the surveys in other wavebands, such as radio, infrared, X-ray and -ray will make substantial contribution to the cross-identification of multi-waveband of celestial objects.

3,  Deng, Licai  (邓李才)

     National Astronomical Observatories

Chinese Academy of Sciences

20A Datun Road, Chao-Yang District, 

Beijing, 100012,

P.R. China

Email: licai@bao.ac.cn

Title of talk: Observational constraints of Simple Stellar Population model and a new approach

Abstract: The concept of simple stellar population (SSP) in its classical scheme is defined as stars born at the same time with the same chemical abundance, and the theoretical model for it is made based on the theory of single star evolution. Observations of the real counterpart of SSPs, star clusters, show a certain deviations from the theoretical picture. There are stars observed in these stellar populations, which are straggling away from the convectional picture of stellar evolution and are very bright therefore have significant alternations to the integrated properties of SSP. In this work, we will demonstrate both observationally and theoretically that inclusion of these stragglers will bring about modifications to age and metallicity measurements of stellar populations, and hence will change the measurements of the basic parameters of galaxies in which the stellar populations are embedded.

4.  Deng, Zugan (邓祖淦)   

        Department of Physics,

Graduate School

Chinese Academy of Sciences

Beijing, 100049

P.R. China

Email: zugan_deng@yahoo.com,

Fax: +86 10 82791548

Cell: +86 10 13522150873

      Title of talk: Structural properties and scaling relations of early-type galaxies from the Sloan Digital Sky Survey

       Abstract: A representive sample of 150 local bright early-type galaxies has been selected from Data Release 2 (DR2) of Sloan Digital Sky Survey (SDSS). Two-dimensional bulge/disk light decomposition has been performed with GIM2D in both g- and r- bands by assuming that bulge and disk of a galaxy can be described with a S$\acute{e}$rsic and a exponential light profile respectively. Parameter $<a_4/a>$ which indicates deviation of isophote from pure ellipses has been carried out by IRAF task $ellipse$ for each galaxy. Analyses of our results confirm correlation between bulge-to-total light ratio (B/T) and S$\acute{e}$rsic index $n_B$ as well as between bugle and disk scale sizes as reported by former researchers. However, no significant correlation between B/T to the isophote shape parameter $<a_4/a>$ has been found. From decomposition in both g- and r- bands, it has been found that disks and bulges components have nearly the same color, this fact may show that they have nearly the same stellar populations. Both bulge and disk components satisfy color-magnitude relation (CMR) well. In average, disk components of early-type galaxies satisfy color-magnitude relation with slope as the same as that of disks of late-type spiral galaxies but slightly shift to redder side. It may imply the difference of the stellar populations in these two disks. As Investigate the distribution on Fundamental Plane in $\kappa$ space, it is found that galaxies with higher B/T appear to have distribution in $\kappa$ space tighter and closer to the so-called "zone of avoidance" than galaxies with lower B/T do. It may hint that scatter in distribution on the Fundamental Plane might be caused by the existence of disks. Our analysis indicate that for early-type galaxies kappa_1 + kappa_2 correlate with (g-r) color significantly and have trendence to correlate with B/T but none with shape parameter a_4/a.

5.  Fang, Li-Zhi  (方勵之)  

         Department of Physics

University of Arizona,

Tucson, AZ 85721

USA

Email: fanglz@physics.arizona.edu

     Title of talks: Stories of SN 1006 in Chinese literatures

      Abstract: The historical records of supernova 1006 AD in Chinese literature will be presented. I will also present the story of astrology related to SN 1006, which is valuable to identify false information.

     Title of talks: 21 centimeter emission from the first generation of stars

  Abstract: 21 cm emission of neutral hydrogen is a powerful tool to study the history of reionization, and, especially the formation and evolution of the first generation of stars. In the first stage of reionization, the field of hydrogen gas has a patchy structure, i.e. most space is filled by neutral hydrogen in low temperature, but fully ionized patches with high temperature around isolated UV photon sources appear. The 21 cm emission of these patches probably is first observable signal at the end of dark ages. I will present the analytical and numerical results of 21 cm emission from the first generation of UV sources.

6.  Feng, Long-Long  (冯珑珑) 

        Purple Mountain Observatory

        Chinese Academy of Sciences

        2 Beijing, Xi Lu

        Nanjing, Jiangsu, 210008

        P.R.China

        Eamil: fengll@pmo.ac.cn

     Title of talk:  Simulating Star Formation in Disk Galaxies

7.  Lee Da-Shin  (李大興)

      Department of Physics

      National Dong Hwa University,

      1 Da Hseuh Rd, Sec 2, Shoufeng,

Hwalien 974

      Taiwan

      Email: dslee@phys.ndhu.edu.tw

      Fax: +886-3-8633690

    Title of talk: Influence on electron coherence from quantum electromagnetic fields in the presence of conducting plates

    Abstract: The influence of electromagnetic vacuum fluctuations in the presence of the perfectly conducting plate on electrons is studied with an interference experiment. The evolution of the reduced density matrix of the electron is derived by the method of  influence functional. We find that the plate boundary anisotropically modifies vacuum fluctuations that in turn affect the electron coherence. The path plane of the interference is chosen either parallel or normal to the plate. In the vicinity of the plate, we show that the coherence between electrons due to the boundary is enhanced in the parallel configuration, but reduced in the normal case. The presence of the second parallel plate is found to boost these effects.  The potential relation between the amplitude change and phase shift of interference fringes is pointed out. The finite conductivity effect on electron coherence is discussed.

8.  Lee, Wolung  (李沃龍)

       Department of Physics

       Taiwan Normal University

       88，Sec.4, Ting-Chou Rd,

       Taipei, 116

       Taiwan

       Email: leewl@mail.sinica.edu.tw

       Fax: +86 10 13522150873

     Title of talk: Quantum noise and a low cosmic microwave background quadrupole

     Abstract: Considering the coupling of the inflaton to the quantum environment, we propose that cosmological density perturbations may arise from inflationary fluctuations induced by the colored quantum noise.  A time scale for the growth of

fluctuations naturally emerges in response to the driving force of the noise, resulting in a suppression of large-scale density perturbation. This may explain the observed low quadrupole in the WMAP cosmic microwave background anisotropy data and potentially unveil the initial time of inflation.

9．Qin, Bo  (秦波)

       National Astronomical Observatories

       Chinese Academy of Sciences

       A20 Datun Road, Chaoyang

       Beijing 100012

       P.R.China

       Email: qinbo@bao.ac.cn

       Fax: +44-1865-273390

Title of talk: Dark Matter and Extra Dimensions

Abstract: Recent observations suggests that our standard picture of the "collisionless cold dark matter" model may have problems, and that dark matter particles may have considerable self-interaction. We find that this self-interaction is a natural consequence of a world with 3 large extra dimensions, where gravity diviates from Newtonian gravity in submillimeter scales and takes the r^{-5} law. We also study the enhanced gravity in large extra dimension scenarios and its implications for dark matter direct detections.

10．Wu, Xiang-Ping （武向平）

       National Astronomical Observatories

       Chinese Academy of Sciences

       A20 Datun Road, Chaoyang

       Beijing 100012

       P.R.China

       Email: wxp@bao.ac.cn

    Title of talk: Construction and Performance of 21 Centimeter Array (21CMA)

Abstract: 21CMA is an interferometric radio array dedicated to measurement of  the redshifted 21 cm emission/absorption signatures of neutral hydrogen against CMB in the epoch of reionization. The array, located in Xinjiang,  west China, consists of 81 pods with a total of 10287 log periodic antennas. It operates at frequencies from 50 to 200 MHz, covering a redshift range of 6-27. In this talk, I will present the motivation, construction and performance of 21CMA and its impact on our understanding of the history of reionization. 

11.  Xia, Xiaoyang (夏晓阳) 

       National Astronomical Observatories

       Chinese Academy of Sciences

       A20 Datun Road, Chaoyang

       Beijing 100012

       P.R. China

       Email: xyxia@bao.ac.cn

       Fax: 86-22-23540133

    Title of talk: The morphology of luminous infrared Galaxies in the local universe

    Abstract: We study the morphology, stellar mass and star formation rate of 159 local luminous infrared galaxies (LIRGs) using multi-color images from Data Release 2 (DR2) of the Sloan Digital Sky Survey (SDSS). The LIRGs are selected from a cross-correlation analysis between the {\sl IRAS} survey and SDSS. They are all brighter than 15.9 mag in the $r$-band and below redshift $\sim 0.1$, and can be reliably classified morphologically. The fractions of interacting/merging and normal disk galaxies are 48\% and 40\% respectively. The normal disk galaxies tend to have lower infrared luminosity than interacting/merging galaxies and hence become an increasingly important population at lower infrared luminosity. Our results complement and confirm the morphology evolution trend of LIRGs found by Melbourne, Koo \& Le Floc'h (2005) from $z \sim 1$ to $z \sim 0.1$. We also find that about 75\% of disk galaxies in the local LIRGs are barred, indicating that bars play an important role in triggering star formation rates $\ga 20\myear$ in the local universe.   

12.  Xiang Shou-Ping  (向守平)

       Center for Astrophysics

       University of Science and Technology of China

       96 Jinzai Lu

       Hefei, Anhui 230026

       P.R.China

       Email:  xpxiang@ustc.edu.cn

       Fax: 86-551-3601861

    Title of talk: TBA

     Abstract:

 13.  Xu, Haiguang  (徐海光)

     Physics Building 1206

Department of Physics,

Shanghai Jiao Tong University

800 Dongchuan Road, Minhang,

Shanghai 200240, PRC

E-mail: hgxu@sjtu.edu.cn

Tel & Fax: +86-21-5474-2055

Title of talk: 2D metal distribution in the hot gas of the compact group of galaxies HCG 62

Abstract: We present the X-ray imaging spectroscopic study of the compact group of galaxies HCG 62 (z=0,0137) with the high-resolution Chandra ACIS data. By using the Centroidal Voronoi Tessellation arithmetic, we obtain the two-dimensional distributions of the gas temperature and iron-dominated metal abundance. We find that the X-ray emitting gas around the central galaxy is roughly distributed in a symmetric pattern. The gas temperature is about 0.7 keV at the center and then gradually increases with radius to about 1.2 keV in the outermost region of the group. At about 35 kpc to the group center, there is an arc structure where the metal abundance is remarkably high at the 90% confidence level. The arc extends clockwise from the west of the central galaxy to the south and is about 20 kpc in width. The average gas temperature and abundance of this arc region are about 1.30 keV and 0.56 solar, respectively, which are higher than those of the rest regions. Also, the metal abundance shows clear spatial variations up to about 0.8 solar in the metal-rich arc, with its total iron mass estimated to be of the order 1e7 solar mass. It is hard to interpret the origin of this abundance arc in terms of the resonant scatterings due to its asymmetry, nor is it formed by tidal or ram pressure stripping. More possibly, it is caused by massive gas outflows triggered by starbursts and/or merger events in history.

 14．Xue, She Sheng（薛社生）

      ICRAnet

     Piazzale della Repubblica,

     10 - 65100 Pescara,

     Italy

      Email: xue@icra.it

    Title of talk: TBA

    Abstract:

15．Zhang, Tong-Jie  (张同杰)

       Department of Astronomy

       Beijing Normal University

       Beijing, 100875

       P.R.China

       Email: tjzhang@bnu.edu.cn

     Title of talk: X-ray emission of baryonic gas in the universe: luminosity - temperature relationship and soft-band background

     Abstract: We study the X-ray emission of baryon fluid in the universe using the WIGEON cosmological hydrodynamic simulations. It has been revealed that cosmic baryon fluid in the nonlinear regime behaves like Burgers turbulence, i.e. the fluid field consists of shocks. Like turbulence in incompressible fluid, the Burgers turbulence plays an important role in converting the kinetic energy of the fluid to thermal energy and heats the gas. We show that the simulation sample of the $\Lambda$CDM model without adding extra heating sources can fit well the observed distributions of X-ray luminosity versus temperature ($L_{\rm x}$ vs. $T$) of galaxy groups and is also consistent with the distributions of X-ray luminosity versus velocity dispersion ($L_{\rm x}$ vs. $\sigma$). Because the baryonic gas is multiphase, the $L_{\rm x}-T$ and $L_{\rm x}-\sigma$ distributions are significantly scattered. If we describe the relationships by power laws $L_{\rm x}\propto T^{\alpha_{LT}}$ and $L_{\rm x}\propto \sigma^{\alpha_{LV}}$, we find $\alpha_{LT}>2.5$ and $\alpha_{LV}>2.1$. The X-ray background in the soft $0.5-2$ keV band emitted by the baryonic gas in the temperature range $10^5<T<10^7$ K has also been calculated. We show that of the total background, (1) no more than 2\% comes from the region with temperature less than $10^{6.5}$ K, and (2) no more than 7\% is from the region of dark matter with mass density $\rho_{\rm dm}<50 \bar{\rho}_{\rm dm}$. The region of $\rho_{\rm dm}>50\bar{\rho}_{\rm dm}$ is generally clustered and discretely distributed. Therefore, almost all of the soft X-ray background comes from clustered sources, and the contribution from truly diffuse gas is probably negligible. This point agrees with current X-ray observations.

 16.  Zheng, Wei  (鄭瑋)  (May be)

       Division of Astronomical Sciences

       National Science Foundation

       Arlington, VA 22230

       Phone (703)292-4899

       Email:  wzheng@nsf.gov

       Fax: 1 703 292 9034

     Title of talk: In Search for Extremely Young Galaxies with "Cosmic Lens"

     Abstract: Significant progress has been made in our understanding of the universe at redshift of ~6, as the results of GOODS, UDF and other studies. We have carried out a search of z-band dropouts in the clusters that have been observed by the HST/ACS. The lensing effect of the clusters enhances our search power and enables us to find more than a dozen candidates of galaxies at redshift of 7-8. Some of these objects are very bright, making it possible for spectroscopic followup observations. I will describe the implications to the reionization history of the intergalactic medium, review other search efforts and discuss the prospect of using gamma-ray bursts to find objects at even higher redshift.

 17.  Zhu, Xing-Fen （朱杏芬）

      Center for Astrophysics

      University of Science and Technology of China

      96 Jinzai Lu

      Hefei, Anhui 230026

      P.R.China

      Email: zhuxf@ustc.edu.cn

      Fax: 86-551-3631760

     Title of talk: Probing the topology of empty and filled regions of galaxies in the Universe