CosPA 4

Frontier Observation in Optical and Infrared Astronomy

The partner universities (Taiwan, Central, and Tsing-Hua) and Academia Sinica will form a consortium. This Taiwan consortium will gain access of a major OIR telescope facility by taking part in the development of a new instrument for the telescope and sharing the cost to build it. The most suitable facility seems to be the Canadian-French-Hawaiian Telescope. It is well equipped with many forefront user-friendly instruments. Its adaptive optics and superb seeing enable it to achieve near IR angular resolution even supercedes that of the Hubble Space Telescope. When studying clusters of galaxies for observational cosmology purposes, CFHT can complement AMIBA in many ways. For instance, its multi-object spectrograph can measure red shifts of galaxy clusters detected through their S-Z effects up to Z=0.08. With careful choice of filters and calibration, photometry can extend this to Z=1.4. Such data sets would be crucial for both the determination of cosmological parameters and the testing of different evolution models of large structures in the universe. Another example is to take advantage of its forthcoming wide field (1 sq. degree!) camera to study the weak shear on the background galaxies in the outer regions of nearby clusters of galaxies. The result would be invaluable for probing the distribution of dark matter in clusters. The synergism between the OIR observation proposed here and the radio and theory efforts proposed in projects no. 1 and 2 for cosmology simply can not be over emphasized. Moreover, we should not forget that great power of CFHT can also be brought to bear on other exciting subjects in modern astrophysics. Examples are studying the Kuiper Belt, the new home for comets in the outer solar system, or IR imaging of the birth of young stars inside dense molecular cloud cores. In addition to CFHT, there are three other alternative organizations of possible collaboration, United Kingdom IR Telescope in Hawaii, University of Hawaii's Inst. For Astronomy, and University of Arizona's Steward Observatory. Equally important is the benefit of the present proposal on improving the infrastructure for OIR astronomy in Taiwan. The successful development of Taiwan's radio astronomy demonstrates the effectiveness of a three phased growth strategy: (1) the access to the Berkeley-Illinois-Maryland mm-wave Array enables Taiwan to attract a team of active radio observers; (2) the collaboration with SAO to construct world's first sub-mm array according to SAO's design stimulates Taiwan to build up the infrastructure for radio instrumentation; (3) the proposal of designing a highly competitive specialized array, AMIBA, the center piece of the present package, signifies Taiwan's attainment of scientific and technological maturity in this field. To access a major OIR telescope and to participate in building a backend instrument (such as the Wide field IR Camera on CFHT) proposed here serve as phases (1) and (2) for the growth of OIR astronomy in Taiwan along this proven path of infrastructure building through international collaboration. To help infrastructure building, ASIAA will put its technical strength behind the instrument effort and NCU will upgrade its Lu-Lin station at Yu-Shan National Park to serve as the domestic training ground for the entire consortium (project no. 5). To aid international collaboration, the PI will apply the skills gained from helping to launch Taiwan's radio effort whereas both Co-Is will exploit their considerable experience in the world arena. To provide expert guidance, an impressive group of world class astronomers of Chinese origin, who are either very active observers doing cosmology on large telescopes or experts in OIR instrumentation, has been organized. They are committed to advise, to collaborate, to evaluate, to educate by spending significant time in Taiwan, and to open their labs for training Taiwan personnel. When carried out, the action proposed here will no doubt lead to Taiwan's ability to conduct high-impact astronomical research via the important OIR window at the dawning of the new millenium.