臺北天文館學報 JTAM Vol.4 中國天文學會 2006 年研討會論文摘要 Abstracts of CAST Symposium 2006 SMA Observations of Star Forming Regions [Oral 1-1] Sheng-Yuan Liu ASIAA The SMA Team Abstract The Submillimeter Array (SMA) located atop of Mauna Kea in Hawaii is a collaborative project of the Smithsonian Astrophysical Observatory (SAO) and the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA). With its coverage over the submillimeter regime of the EM spectrum, the SMA best probes in high angular resolution the dense and warm material (including both gas and dust) particularly associated with the dynamical and often energetic processes in the formation of stars and planetary systems. This presentation gives recent results obtained with the SMA in the area of star formation. These studies covers phenomena associated with low- and high-mass young stellar objects such as dense cores, circumstellar disks, jet and outflows, as well as the complex chemical processes within. ASIAA-SMA Seyfert Survey [Oral 1-2] Matsushita, S. Inst. of Astronomy and Astrophysics, Academia Sinica, Taiwan ASIAA-SMA Extragalactic Group Abstract Seyfert activity is believed to be powered by a supermassive black hole, and the fuel for the activity is believed to be supplied from dusty disk/torus surrounding the supermassive black hole. In addition, a broadly accepted model (unified scheme) suggests that the type of the Seyfert (type 1 and 2) can be explained with the viewing angle of the circumnuclear dusty disk/torus (whether it obscures the supermassive black hole or not). Molecular gas in submillimeter-wave, such as higher-J CO lines, can trace warmer and denser molecular gas selectively, and therefore it is suitable to study the distributions, kinematics, and physical conditions of the circumnuclear disk/torus, and the relation between the Seyfert activities and also the large-scale strucutres. Here, we present the current status of the ASIAA-SMA Seyfert Survey. So far, we observed one Seyfert 1 galaxy and three Seyfert 2 galaxies. Most of the galaxies (three out of four) show possible molecular gas concentrations with rotating features at the nuclei, and multi-line CO studies show these central components are warm and dense. We will discuss more details in the talk. Instrumentation and Science with the CFHT [Oral 1-3] Jeremy Lim ASIAA Abstract Taiwan astronomers have access to the Canadian-France-Hawaii Telescope (CFHT) through participation in the Wide Field Infrared Camera (WIRCam) project. Here I give an overview of the telescope, focussing in particular on the instruments that are especially competitive or unique, and examples of the science being conducted with these instruments. I also briefly review the process of applying and allocating time on the telescope. The CFHT provides an opportunity to develop a broader optical/IR community in Taiwan, and we hope this review will encourage more Taiwan astronomers to conduct research with this telescope. - 45 - 中國天文學會 2006 年研討會論文摘要 Abstracts of CAST Symposium 2006 CFHT Megacam I and z Survey of DEEP2 Field [Oral 1-4] Hsieh, B. C. Inst. of Astronomy and Astrophysics, Academia Sinica, Taiwan Lin, Lihwai Inst. of Physics, National Taiwan Univ., Taiwan Abstract The photometric redshift technique is a good utility for extragalactic studies. However, the redshift limitations of most published photometric redshift catalogs are less than 0.7. Although there are few catalogs containing objects with redshift higher than 1.0, the templates for these photometric redshift estimations are inadequate to derive accurate photometric redshifts for high-z objects. The DEEP2 project provides tens of thousands spectroscopic redshifts up to z=1.5, which is an excellent template for the photometric redshift method to estimate the redshift at high-z. Therefore, we proposed the CFHT Megacam observation of DEEP2 field for filter i and z for 21 hours. By combining the data with the B, R, I observation of DEEP2 field, a photometric redshift catalog for DEEP2 field is generated. The catalog is ideal for studies of large scale structure, galaxy formation/evolution, and galaxy cluster/group/pair finding. In this talk, we will present the latest results of our studies. Iapetus and Enceladus as seen from Cassini [Oral 1-5] Wing-Huen Ip Inst. of Astronomy and Space Science, National Central Univ., Taiwan Wei-Ling Tseng Inst. of Astronomy, National Central Univ., Taiwan Lily Lin Inst. of Space Science, National Central Univ., Taiwan Jinnee Wang Inst. of Astronomy, National Central Univ., Taiwan Abstract While Titan remains to be the central focus of the Cassini-Huygens mission, two rising stars have been found. They are Iapetus and Enceladus, respectively. Iapetus is interesting because of the remarkable dichotomy in its surface brightness distribution with the albedo on the leading emisphere a factor of ten darker than the trailing hemisphere. The origin of such albedo asymmetry is still to be explained satisfactorily. But recent Cassini observations by the imaging SSI experiment onboard has shown that this medium-sized satellite (radius ~ 720 km) has a slightly ellipsoidal shape which might be indicative of an unusual tidal despinning history. In addition, Iapetus equator is lined up with a curious mountain ridge system probably as old as the satellite itself. The formation of this equatorial ridge system could be related to the tectonic process accompanying the tidal despinning or the collisional imprint of a primordial ring system. Iapetus is thus a representation of the satellite formation process in the days long gone. On the contrary, the small icy satellite Enceladus (radius ~ 250 km) displays an amazing level of outgassing activity. The recent Cassini SSI report of possible presence of liquid water on its surface is even more of a shock to planetary science. In this talk some of these interesting results will be summarized. AMiBA Science [Oral 2-1] Jiun-Huei Proty Wu Dept. of Phys. NTU, Taiwan Abstract The Array for Microwave Background Anisotropy (AMiBA) is a Taiwanese project to observe the Cosmic Microwave Background (CMB). It is led by a joint effort from the Academic Sinica Institute of Astronomy and Astrophysics (ASIAA) and the Institute of Astrophysics at National Taiwan University (IoAp, NTU). I will give an overview on the science goals of the project, with particular emphasis on the Sunyaev-Zel'dovich effect, the CMB polarization, and the cosmic strings. We expect the project to enhance not only our understanding of the universe, but also the competitiveness of Taiwan in the - 46 - 臺北天文館學報 JTAM Vol.4 international cosmology community. Ultra-Wideband Digital Correlator of Upgraded AMiBA [Oral 2-2] H.H. Li, S.K. Wong & T. Chiueh Institute of Astrophysics & Department of Physics, National Taiwan University Abstract In the upgraded AMiBA to begin operation in early 2007, the bandwidth will increase from 18Ghz to 35Ghz so as to compensate for the sensitivity loss of a 13-element array compared with the original 19-element array. In addition, to circumvent the 50% efficiency loss of analog correlation present in the current version of AMiBA due to its wide band, a world fastest digital correlator, able to process signals of 10Ghz bandwidth, is being developped. We report the design and progress of this digital correlator. SZ Effect from Secondary Electrons in Clusters of Galaxies [Oral 2-3] Hwang, Chorng-Yuan Graduate Institute of Astronomy, National Central University, Taiwan Abstract Secondary electrons will be produced in interactions between cosmic rays and thermal plasma. This process in galaxy clusters will continuously last longer than a Hubble time because the cosmic ray protons contained within the galaxy clusters have a lifetime longer than the age of the cluster. These secondary particles in the galaxy clusters will scatter the cosmic micro-wave background photons and produce a non-thermal SZ effect in addition to the thermal SZ effect caused by the thermal plasma in the clusters. We derive the non-thermal SZ effect from the secondary electrons under a variety of scenarios and discuss our findings in relation to observations. X-shaped sources: An unusual result at low radio frequency [Oral 2-4] Lal, D.V. Institute of Astronomy and Astrophysics, Academia Sinica, Taiwan, R.O.C. Rao, A.P. National Centre for Radio Astrophysics, TIFR, Pune, India. Abstract Lal & Rao (2005) reported an unusual result for 3C~223.1, an X-shaped radio source, i.e., the wings (or the low-surface-brightness jets) have flatter spectral indices with respect to the high-surface-brightness (active) jets, using low frequency data from Giant Metrewave Radio Telescope (GMRT). This clearly shows the value of mapping the sample of X-shaped radio sources at low frequencies to understand the formation scenario of these sources. We have now obtained GMRT data for almost all of the X-shaped radio sources, performed in a uniform way. Here, we will present our results from the GMRT radio images at 240 and 610 MHz for these sources with an aim to test the formation models of these sources. Dynamical History of Galaxy Encounters [Oral 2-5] Sun, W.H. Institute of Astronomy, National Central University Abstract I will review the several cases of interacting galaxies in which low surface brightness extension around the galaxies and/or faint, diffuse emission have been detected. Multi-wavelength observations of these galaxies reveal the fact that often the diffuse emission are both gaseous and stellar in nature. By studying the spectral energy distributions of the stellar components and comparing to that of the member galaxies, - 47 - 中國天文學會 2006 年研討會論文摘要 Abstracts of CAST Symposium 2006 as we have done using the BATC archive, the origin of the scattered stars can be studied, which allows us to trace back and delineate the interacting process among the participating galaxies. Structure and Kinematics of CO 2-1 Emission in the Central Region of NGC4258 [Oral 2-6] Sawada-Satoh, S.