The Caltech Submillimeter Observatory employs a precision 10.4-meter-diameter telescope operating within a dome to observe the sky at submillimeter wavelengths. This award will continue funding for the next three years for observatory operations, staff and student support, and for instrumentation development. Areas of research will include studies of molecular gas and dust in distant primeval galaxies, large-scale imaging of star-forming clouds using powerful new bolometer cameras, and observations of the Sunyaev-Zeldovich effect on the cosmic microwave background. Instrumentation will be developed to increase overall system sensitivity and mapping speed. The CSO trains many undergraduate students, graduate students and postdoctoral fellows, in both observational science and instrumentation development. A considerable fraction of telescope time is allocated to students, both at Caltech and at other institutions; overall, more than 50% of telescope usage is by astronomers from outside of Caltech. The CSO is noteworthy for its pioneering research in astronomical receiver and bolometer technology, which is used at many other observatories both national and worldwide. A new bolometer camera system based on Microwave Kinetic Induction Devices (MKIDs) will be developed and used on the telescope during this award period.
Water at the Edge of the Universe For 25 years, the Caltech Submillimeter Observatory has been studying the interstellar medium from the Milky Way to distant galaxies. In a recent study, an international team of astronomers led by the California Institute of Technology and involving the University of Colorado Boulder has discovered the largest and farthest reservoir of water ever detected in the universe. The amount of water is estimated to be at least 100,000 times the mass of the sun. This discovery shows that water was abundant when the universe was only about 1.6 billion years old and provides a probe of conditions occurring in distant quasars. The finding also highlights the usefulness of the millimeter and submillimeter band for astronomy research. The huge water vapor cloud was found in a distant quasar--one of the most powerful objects in the universe that pumps out the energy equivalent of 1,000 trillion suns--about 65,000 times that of the Milky Way galaxy. The quasar's power comes from matter spiraling into the central, supermassive black hole. Because the quasar--essentially a voraciously feeding black hole--is so far away, its light has taken 12 billion light years to arrive at Earth. To sense the water vapor, the researchers used a spectrograph called Z-Spec at the Caltech Submillimeter Observatory (CSO), a 10-meter-diameter telescope near the summit of Mauna Kea on the big island of Hawaii. Z-Spec's detectors are cooled to within 0.06 degrees Celsius of absolute zero in order to obtain the sensitivity required for these measurements. In a separate study, the same instrument was used, together with other ground-based facilities, to measure the precise redshift of a massive starforming galaxy at the edge of the Universe. These measurements reveal the presence of a hundred billion solar masses of gas, which is being converted into stars at a rate more than 2000 times that of the Milky Way.
