CSO to End Operations

Caltech Submillimeter Observatory in Hawaii to End Operations

After almost 29 years, the California Institute of Technology (Caltech) will end operations of the Caltech Submillimeter Observatory (CSO) in Hawaii in September, 2015. As previously announced, Caltech will begin the planning for the dismantling of the observatory. This process will be planned in close coordination with the Office of Mauna Kea Management, University of Hawaii at Hilo, to ensure that it is undertaken promptly and in a culturally and environmentally respectful manner. Caltech is sincerely grateful to the people of Hawaii Island for the use of Maunakea for nearly three decades, enabling superb research from this excellent astronomical site for the betterment of humanity. Caltech commits to the dismantling of the telescope and site restoration according to the Decommissioning Plan approved by the Board of Land and Natural Resources.

The CSO is a cutting-edge facility for astronomical research and instrumentation development. The CSO’s 10.4-meter radio telescope was designed and assembled in the 1980s by a team led by the late Robert Leighton, Caltech’s Valentine Professor of Physics. Under the leadership of CSO founding director Tom Phillips, the John D. MacArthur Professor of Physics, Emeritus, at Caltech, new instrumentation for the CSO was developed over the years by Caltech faculty, students, and staff; by staff scientists from NASA’s Jet Propulsion Laboratory (which is managed by Caltech); and by collaborators at institutions around the world.

Located near the summit of Maunakea, the CSO began operation in early 1987, under the management of Caltech by agreement with the University of Hawaii. For nearly three decades, astronomers from around the world have used the observatory to pursue research and to accomplish groundbreaking achievements in submillimeter and millimeter astronomy—the study of light emitted by atoms, molecules, and dust grains in the interstellar space where stars and planets form. Well over 100 students, from Caltech and other institutions, have used the CSO for their PhD research.

“The CSO has played a central role in the development of the science and instrumentation of submillimeter and millimeter astronomy over the last three decades,” says Sunil Golwala, current director of the CSO and a professor of physics at Caltech. “The CSO legacy of combining training in instrumentation development, hands-on observing, and science will live on via its former students and researchers as well as in new projects for which it has laid the foundation.”

“This has been a most exciting time in which the field of submillimeter astronomy has been developed, leading to an understanding of astrochemistry, star formation, and distant, dust-obscured galaxies,” says Phillips, now the CSO’s director emeritus. “We thank the National Science Foundation, which funded the CSO continuously from construction in 1984 to the end of 2012.”

“The CSO has been foundational in creating the thriving discipline of submillimeter astronomy,” says Tom Soifer (BS ’68), Kent and Joyce Kresa Leadership Chair of Caltech’s Division of Physics, Mathematics and Astronomy. “It is with a deep sense of gratitude to the people of Hawaii that we thank them for hosting this magnificent facility for all this time.”

CSO Scientific Achievements

• Development of superconducting-tunnel-junction detectors and spiderweb bolometers for radio astronomy, now commonly used on ground- and space-based radio observatories (ALMA, CARMA, Herschel, Planck), as well as the first astronomical demonstrations of an emerging new technology, kinetic inductance detectors.
• Determination of the role of atomic carbon in the interstellar medium.
• Detection of the submillimeter “line forest” using the line-survey technique, as well as of key hydride molecules, which has led to an improved understanding of interstellar chemistry.
• Discovery of a new phase of stellar evolution for red giant stars, which occurs just before they completely lose their envelope of gas during the formation of planetary nebulae.
• Mapping of the molecular gas of the radio galaxy Centaurus A, among others.
• Determination of the volatile composition of comets, including the first ground-based detection of HDO (heavy water) in a comet, leading to an improved understanding of the origin of comets and of terrestrial water
• Discovery of ND₃, a rare type of ammonia, with emission about 11 orders of magnitude stronger than initially presumed.
• Discovery of signs of intermittent turbulence in interstellar molecular clouds.
• Use of tools such as the Submillimeter High Angular Resolution Camera (SHARC) to image distant, dusty galaxies that are difficult to observe with optical telescopes.
• Spatially resolved imaging of nearby stellar debris disks, using SHARC, providing evidence for the presence of planets in these systems.
• Spectroscopy of distant and local galaxies using the Z-Spec spectrometer—developed at CSO—which has helped yield a better understanding of the processes of galaxy formation and provides a method for measuring galaxies that are too dusty to be seen with optical instruments.
• Mapping of the pressure in the gaseous component of massive galaxy clusters via its interaction with the cosmic microwave background (the thermal Sunyaev-Zel’dovich effect).
• The first detection of the change in the cosmic microwave background caused by its interaction with the gaseous component of a high-speed subclump within a massive galaxy cluster (the kinetic Sunyaev-Zel’dovich effect).