This is a collaborative project led by Dr Cowie. Sub-millimeter observations with the revolutionary SCUBA camera on the James Clerk Maxwell Telescope on Mauna Kea, Hawaii, revealed the existence of a population of dust-obscured, ultra-luminous galaxies that dominates star formation in the high-redshift Universe. The new camera, SCUBA-2, speeds up the mapping of wide fields by almost three orders of magnitude, and will dramatically expand understanding of the sub-millimeter Universe and the history of dusty star formation. This project will carry out a SCUBA-2 survey of two heavily studied fields of the Great Observatories Origins Deep Survey (GOODS), during weather conditions suitable for observing at a wavelength of 450-microns. Since the confusion limit is lower at this wavelength, which is shorter than other wavelengths used, these data will be able to (i) measure the more typical sources contributing to the sub-millimeter background, (ii) measure fluxes close to the rest wavelength peak of the blackbody distribution, and (iii) obtain much more accurate positions for the sources. Combining the sub-millimeter data with radio, infrared, optical, and X-ray data, from space and from the ground, will determine the multi-wavelength properties of the distant, heavily dust-obscured sources, and provide accurate positions for spectroscopic follow-up. The research will determine redshifts, luminosities, and star formation rates, and thus trace the extent and evolution of obscured star formation in the distant Universe.
Understanding the star formation history of the universe is a major goal of modern astronomy, and of great public interest. This research will inform popular science articles, web sites, and frequent talks to broad sections of the technical and lay communities. Previous data collected by these investigators have been made available to the community and have proved valuable for many outside projects: this practice of regular release will continue with the new survey data. Both investigators continue to promote diversity and cultural interaction at their respective institutions, including students from throughout the Pacific arena (in Hawaii), and a strong effort to involve women (in Wisconsin), who remain a vastly under-represented group.
One of the main goals in cosmology is to map the history of the formation of galaxies over cosmic time. Over the last two decades there has been enormous progress in determining this history. However, one major problem is that much of the light produced in the galaxies is obscured by dust. This light is reradiated by the glowing dust in the far infrared. Much of the galaxy light is missed in this way. For the most massive galaxies, where the effects of the dust are largest , the galaxies are often completely unseen in the optical. The primary goal of this proposal was to carry out a detailed study of these far-infrared dominated galaxies using a new camera SCUBA-2 on the JCMT 15m telescope on Mauna Kea.This revolutionary camera, which works at wavelengths of 450 and 850 microns, allowed us to measure the population of galaxies that dominate the light at 450 microns. We used measurements with interferometers (the submillmeter array on Mauna Kea and the radio VLA) to piinpoint the positiions of the dusty galaxies. We then combined with other data to determine the redshifts, bolometric luminosities, and star formation rates of the galaxies. We showed that the population of obscured galaxies is a substantial part of the galaxy formation history over much of cosmic time (out to redshifts beyond 5) and that most of the most massive galaxies are formed in this way. All of the goals of the program were achieved. The research program trained graduate students in a wide variety of observational techniques. reflecting the wide range of telecsopes the Institute for Astronomy (IFA) at the University of Hawaii has access to. The IFA draws many of its students from the Pacific area, and such training also enhances the cultural interaction with the Japanese, Chinese, Korean, and Taiwanese astronomical communities who are now participating in many of the new observational facilities under construction. This includes the Thirty meter telescope which will be built in Hawaii. One Taiwanese graduate student Dr TC Chen obtained his PhD working on the 450 micron galaxies. A second student Dr Ryan Keenan from Wisconsin obtained his PhD at U Wisconsin Madison working on near infrared data collected under the project and is now a postdoctoral researcher at ASIAA in Taiwan. All of the data has been published in the form of catalogs and the SCUBA-2 data can be accessed through the Canadian data archive CADC.
