FR4: Chinese Speakers Print E-mail

Title: Exploiting the Forthcoming Pan-STARRS Dataset

Speaker: Yan-Chuan Cai

Institution: University of Durham, UK

Abstract: Pan-STARRS (Panoramic Survey Telescope and Rapid Response System) 3pi survey will cover 3/4 of the sky. Its PS1 telescope is expected to detect approximately 23rd magnitude in less than a week. For using the forthcoming Pan-STARRS data to study Large Scale Structure, we have used the Millennium N-body simulation and the GALFORM semi-analytical galaxy formation model to build a mock Pan-STARRS galaxy catalogue. This allows us to determine the basic properties expected for the Pan-STARRS surveys, such as the number counts of galaxies and their redshift distribution. These mocks have been produced for use by the Pan-STARRS consortium to test the performance of photometric redshift estimation codes. Applications of this work such as impact of photo-z errors on the measurement of baryonic acoustic oscillations will be addressed.

Title: Brightest central galaxies and dry mergers

Speaker: Zugan Deng

Institution: Graduate School of the Chinese Academy of Sciences, China

Abstract: A sample of local BCGs selected from C4 cluster has been analysed. Our results show that many BCGs are on going dry mergers. Our evidence shows that the dry merger rate for BCGs is much higher than field elliptical galaxies. Detail research of dry merger may provide important constraints on galaxy formation, especially the formation of most massive galaxies.

Title: 21 cm signals from ionized and heated regions around first stars

Speaker: Li-Zhi Fang

Institution: University of Arizona, USA

Abstract: 21 cm signals from the UV ionizing sources in the reionization epoch is crucial to understand the physics at the end of dark ages. The formation and evolution of 21 cm emission and absorption regions depend essentially on the kinetics of photons in the physical and frequency spaces. To solve the radiative transfer equation, we use the WENO algorithm, which is effective to capture the sharp ionization profile and the cut-off at the front of light and to handle the small fraction of neutral hydrogen and helium in the ionized sphere. We show that a spherical shell of 21 cm emission and absorption will develop around a point source once the speed of the ionization front (I-front) is significantly lower than the speed of light. The 21 cm shell extends from the I-front to the front of light; its inner part is the emission region and its outer part is the absorption region. The 21 cm emission region depends strongly on the intensity, frequency-spectrum and life-time of the UV ionizing source. For a source of short life-time, no 21 cm emission region can be formed if the source dies out before the I-front speed is significantly lower than the speed of light. Yet, a 21 cm absorption region can form and develop even after the emission of the source ceases.

Title: A New Fast Algorithm of Cosmic Statistics for Large Data Sets

Speaker: Long-long Feng

Institution: Purple Mountain Observatory, China

Abstract: Based on the Beylkin-Cramer summation rule, we introduce a new fast algorithm that enable us to explore the high order statistics efficiently in large data sets. Central to this technique is to make decomposition both of fields and operators within the framework of multi-resolution analysis (MRA), and realize theirs discrete representations. Accordingly, a homogenous point process could be equivalently described by a operation of a Toeplitz matrix on a vector, which is accomplished by making use of fast Fourier transformation. The algorithm could be applied widely in the cosmic statistics to tackle large data sets. In the numerical procedures, the algorithm scaled with $O(N\log N)$ is significantly faster than the current particle-based methods, and its computational cost does not relies on shape or size of sampling cells. In addition, based on this technique, we propose further a simple fast scheme to compute the second statistics for cosmic density fields and justify it using simulation samples. Hopefully, the technique developed here allows us to make a comprehensive study of non-Gaussianity of the cosmic fields in high precision cosmology.

Title: Phenomenological Models of Dark Energy

Speaker: Changjun Gao

Institution: National Astronomical Observatories of China

Abstract: two phenomenological models of dark energy are presented. They give a possible explanationfor both the fine-tuning and the coincidence problem. Also they are consistent with the observations very well. The quintessence theory of the models is also constructed.

Title: The first stars, how much we know (review)

Speaker: Liang Gao

Institution: Durham University, UK

Abstract: Here I shortly review the progresses in understanding the formation of the first stars. 6. Title: Cold Gas and Star Formation in Early Universe Speaker: Yu Gao Institute: Purple Mountain Observatory, China Abstract: We are soon-to-be available for the study of star formation in galaxies at high redshift. I will emphasize on the detection of the cold gas most relevant to the active star formation in galaxies in the early Universe, the current status of this research field highlighted by several dozens of CO detections and a few detections in other molecules such as HCN, and future directions in the next few years.

Title: Cold Gas and Star Formation in Early Universe

Speaker: Yu Gao

Institution: Purple Mountain Observatory, China

Abstract: I will try to introduce some major facilities currently available and some soon-to-be available (e.g., two major telescopes ALMA and EVLA) for the study of star formation in galaxies at high redshift. I will emphasize on the detection of the cold gas most relevant to the active star formation in galaxies at high redshift, the current status of this research field highlighted by several dozens of CO detections and a few detections in other molecules such as HCN, and future directions in the next few years.

Title: From galaxy distribution to AGN

Speaker: Yipeng Jing

Institution: Shanghai Astronomical Observatory, China

Abstract: I will talk about recent results from redshift surveys about the galaxy distribution and the environment of AGN, and their implication for thoeretical modeling of galaxy formation.

Title: Primordial magnetic fields from dark energy

Speaker: Wolung Lee

Institution: Taiwan Normal University, Taiwan

Abstract: Evidences indicate that the dark energy constitutes about two thirds of the critical density of the universe. If the dark energy is an evolving pseudo scalar field that couples to electromagnetism, a cosmic magnetic seed field can be produced via spinoidal instability during the formation of large-scale structures.

Title: Strong lensing by clusters of galaxies and searching for high-z object

Speaker: Shude Mao

Institution: University of Manchester, UK

Abstract: I will discuss some recent work on strong lensing by clusters of galaxies, and their cosmological implications. I will give a brief review of searches for high-z objects (by others) using strongly lensed clusters.

Title: Fractional Brownian Motion and halo model

Speaker: Jun Pan

Institution: Purple Mountain Observatory, China

Abstract: Fractional Brownian motion (FBM) is a concept which extends the normal Brownian motion by introducing correlation between steps of corresponding random walks. The idea is to generalise the excursion set theory for halo models with the FBM. The mass function, merger rate, merging history and halo biases are all revisited with the new formalism. Comparison with simulations indicates that the application of FBM is very sucessful and thus we can reliably renovate the halo model to perform analytical theoretical calculation with the spherical collapse.

Title: Extra dimensions: implications for dark matter detection

Speaker: Bo Qin

Institute: National Astronomical Observatories of China

Abstract: If our space has hidden dimensions, gravity would deviate from Newtonian gravity and be greatly enhanced on small distance scales. We show that if these extra dimensions are large and flat, as in the ADD scenario, then the cross section between dark matter and ordinary matter would be increased by many orders of magnitude due to this new gravity. We discuss on possible implications for dark matter detection experiments.

Title: 21 Centimeter Array (21CMA): Probe of the Reionization Epoch

Speaker: Xiang-Ping Wu

Institution: National Astronomical Observatories of China

Abstract: 21CMA is an interferometric radio array dedicated to measurement of the redshifted 21 cm emission 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 reshishift range of 6-27. In this talk, I will present the motivation, construction, performance and progress of 21CMA and its impact on our understanding of the history of reionization.

Title: Dimensionality in Quantum Cosmology

Speaker: Zhong Chao Wu

Institution: Zhejiang University of Technology

Abstract: TBA

Title: Mid-infrared properties of IR QSOs

Speaker: Xiaoyang Xia

Institution: Tianjin Normal University, China

Abstract: We perform the statistical analysis for the mid-infrared properties of IR QSOs based on Spitzer IRS data. By comparing with PG QSOs and ULIRGs, it is clear that the IR QSOs are in the transition stage from massive starburst to classical QSOs. The close anti-correlation between 6.2mum PAH emission and the blueshift of Balmer lines is likely the evidence for the AGN feedback that heats and blows away surrounding cold gas and finally ceases star formation.

Title: Passively Evolving Galaxy Population as Seen by the GOODS Spitzer Observations

Speaker: Haojing Yan

Institution: Carnegie Observatories, USA

Abstract: Using the deep Infrared Array Camera (IRAC) observations of the Great Observatories Origins Deep Survey (GOODS) Spitzer Legacy Program, we construct a large sample of IRAC-selected Extremely Red Objects (IEROs; Yan et al. 2004). Such IEROs are luminous in IRAC passbands, but are very faint or even invisible in optical. Our previous work in the HUDF shows that such a population is likely dominated by very massive, passively-evolving, very old galaxies at z~2.4. This current study will extend to a much wider field, and will investigate 1) the fraction of passively-evolving galaxies; 2) the overlapping fraction between IEROs and other types of red galaxies such as EROs and DRGs; 3) the contribution of IEROs to the global stellar mass density; and 4) their progenitors and descendants.

Title: Cosmology with the Large Synoptic Survey Telescope (review on probes of dark energy)

Speaker: Hu Zhan

Institution: University of California, Davis, USA

Abstract: The proposed Large Synoptic Survey Telescope (LSST) will carry out a deep half-sky 6-band imaging survey, obtaining more than 3 billion galaxies and millions of supernovae. I will discuss the LSST science opportunities with a focus on the techniques of probing dark energy and dark matter, which include weak lensing, baryon acoustic oscillations, type Ia supernovae, and cluster counting. I will present innovative ways of using the survey data that enable better control on systematics and tighten the cosmological constraints. Finally, I will give a brief assessment on observing high-z galaxies and GRBs with LSST.

Title: Wavelet and Weak Lensing

Speaker: Tong-Jie Zhang

Institution: Beijing Normal University, China

Abstract: Weak lesning of galaxies by large scale structure is a poweful tool to mesure the matter density parameter \Omega_m of the universe. In this talk I will talk about the weak lensing of CMB polarization by large scal structure. Wavelet analyse is applied in the smoothing of the lensed convergence, T, E and B mode for CMB. Futher, we get the constraint on the \Omega_m and the equation of state(EoS) w for dark energy.

Title: Dense and Warm Molecular Gas in Prorotypical Ulirg Arp 220

Speaker: Jun-Hui Zhao

Authors: Jun-Hui Zhao and Tao An

Abstract: Arp 220 is the prototypical utltra-luminous infrared galaxy (ULIRG) with Lir = 1.4 x 10^12 solar luminosities. Two compact components in the nuclear region have been observed at radio and IR wavelengths. This galaxy is thought to be in the final stages of galaxy-galaxy merging. Study of Arp 220 could provide us detailed information on the astrophysical processes in the galaxies at high red-shifts. We present the results from SMA observations of Arp 220 in multiple CO transitions of J=6-5, 3-2, 2-1 and the isotope 13CO at J=2-1 at 690, 340 and 230 GHz with the Submillimeter Array (SMA) in angular resolutions of sub-arcsec to a few arcsec. Based on the measured ratios, we modeled the excitation condition of the molecular clouds, suggesting that the CO J=6-5 emission arises from dense (n[H2]~10^5 cm^-3) and warm (Tk ~ 100 K) cloud components. Each of CO J=6-5 clumps contains at least a few times 10^8 solar-mass molecular gas, suggesting presence of a few super giant molecular clouds (GMCs) in Arp 220. The dense, warm molecular clouds are likely to be the consequence of the galaxy merger. Properties determined from the super GMCs suggest that they are in different stages of star formation.

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