| NSF Org: |
AST Division Of Astronomical Sciences |
| Recipient: |
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| Initial Amendment Date: | June 15, 2012 |
| Latest Amendment Date: | June 3, 2014 |
| Award Number: | 1211680 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Matthew Benacquista
AST Division Of Astronomical Sciences MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | July 1, 2012 |
| End Date: | June 30, 2017 (Estimated) |
| Total Intended Award Amount: | $424,175.00 |
| Total Awarded Amount to Date: | $424,175.00 |
| Funds Obligated to Date: |
FY 2013 = $139,773.00 FY 2014 = $144,285.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
W5510 FRANKS MELVILLE MEMORIAL LIBRARY STONY BROOK NY US 11794-0001 (631)632-9949 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
WEST 5510 FRK MEL LIB Stony Brook NY US 11794-3366 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | EXTRAGALACTIC ASTRON & COSMOLO |
| Primary Program Source: |
01001314DB NSF RESEARCH & RELATED ACTIVIT 01001415DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.049 |
ABSTRACT
A longstanding problem in astrophysics is to understand how galaxies form and develop throughout their lifetimes. Such understanding is necessary to uncover how our Universe evolved and to gain insight into the origin of our own Milky Way Galaxy. One important aspect of understanding galaxy formation and evolution is to develop detailed theories of star formation. As star formation occurs in giant molecular clouds (GMCs) within galaxies, astrophysicists study the formation and evolution of GMCs. With unprecedented high quality and high resolution data, this study will explore the evolution of GMCs and consequent star formation in galactic disks, and it will critically and quantitatively reconsider the standard picture of gas evolution in galaxies, specifically the one driven by stellar feedback. The study enables for the first time a census of GMC populations in substantial spiral galaxies.
This project will also serve as a prototype for research with the Atacama Large Millimeter/submillimeter Array (ALMA) (a new international facility funded in part by the National Science Foundation), which will resolve the internal structure of GMCs in nearby galaxies and routinely produce images of molecular gas and star formation in very distant galaxies. For this project the investigators will use observations from their new CO survey of nearby galaxies with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) and the Nobeyama Radio Observatory 45m telescope (NRO45), a survey that is nearly complete. The investigators will release to the astronomical community the CO data of nearby galaxies from CARMA and NRO45, and they will also release the software for the combination of interferometer and single-dish data developed for the survey.
The investigating team also plans educational and outreach activities that involve building a radio interferometer for a hands-on astronomical laboratory course and disseminating the course materials to other schools. Because the concept of interferometry is challenging to master, developing such a hands-on laboratory course is crucial to the education of the next generation of radio astronomers for the ALMA era.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Intellectual Merit
Molecular clouds are concentrations of a huge amount of molecular gas in interstellar space. Their masses often reach as much as million times the mass of the Sun. Molecular clouds are the birthplace of virtually all stars in galaxies, as such a huge amount of gas naturally leads to star formation. Understanding molecular clouds is, therefore, necessary for understanding star formation. However, a question as to how such molecular clouds are assembled and maintained in galaxies has remained uncertain. Until recently, textbooks presented only a working hypothesis that molecular clouds are accumulated from diffuse atomic gas in the interstellar space. As they become dense, the gas phase changes from atomic to molecular, resulting in star formation. This NSF project called for a paradigm shift. By observing molecular gas in many galaxies in the Local Universe, we found that molecular clouds do not go back to the atomic phase in a significant way. They stay as dense molecular clouds, but are sometimes fragmented to smaller clouds, and then are coagulated back to larger clouds. The process of the coagulation and fragmentation is helped by dynamic motions of gas around large galactic structures, such as spiral arms. Therefore, star formation and galaxies are dynamically linked. The previous textbook picture applies only to the outskirts of galaxies, but in the main parts of the galaxies, we need to adopt the new picture of molecular gas evolution as proven by this project (see Image 1).
Broader Impacts
This NSF project utilized the technique called radio interferometry. Interferometry is becoming more and more important in astronomy, but the technique is too complicated for typical students to understand without hands-on experiment. We therefore developed a low-cost radio interferometer for education, using the parts mostly from shelves in electronic and hardware stores, such as TV satellite dish and receiver, man-hold ladder, plywood, and kitchen aluminum foil, etc. With this interferometer, we developed an astronomy laboratory course in which students measure the diameter of the Sun. This work was published in a leading journal of physics education and made a cover page (see Image 2). A copy of the interferometer is being built in other universities, which help training astronomers of future generations.
Last Modified: 09/28/2017
Modified by: Jin Koda
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