Understanding how galaxies form and evolve across cosmic time is one of the central challenges of modern astrophysics. In the last fifteen years, astronomers have learned a great deal about distant galaxies in the early universe by studying the properties of their stars; however, much less is known about the properties of their gas, especially the relatively cool and diffuse material in which hydrogen is atomic (rather than ionized or molecular) in form.

This project will take an important first step toward understanding the universe's neutral atomic hydrogen by catalyzing a new international collaboration that has been approved to conduct a 5000-hour survey with an array of radio telescopes being built in South Africa. The new array is known as MeerKAT, and the new survey has adopted the name "Looking At the Distant Universe with the MeerKAT Array" or LADUMA. NSF funding will allow 12 U.S. scientists to attend the LADUMA survey's inaugural "all hands" collaboration meeting in Cape Town, South Africa in late 2011 or early 2012. The local host will be Dr. Sarah Blyth of the University of Cape Town, who shares leadership duties for LADUMA with Dr. Benne Holwerda of the European Space Agency and Dr. Andrew Baker of Rutgers, the State University of New Jersey.

The U.S. delegation will feature student participation and include representation from Rutgers, the National Radio Astronomy Observatory, the University of Arizona, the University of California at Berkeley, the University of Colorado, the University of New Mexico, the University of North Carolina, the University of Wisconsin, and West Virginia University.

The intellectual merit of this project derives principally from the immense scientific potential of a survey that will ultimately be able to detect neutral atomic gas at an epoch when the universe was less than half its present age. The collaboration's first "all hands" meeting will bring together radio, optical, and theoretical astronomers from across the 56-person team to determine the optimal strategy for the survey and to lay the groundwork for focused preparatory efforts in key areas, such as the acquisition of complementary data with other telescopes and the establishment of joint supervision of students. Because Cape Town is the location of the MeerKAT engineering office, the meeting will also allow face-to-face discussions between LADUMA scientists and MeerKAT engineers.

The broader impacts of the LADUMA collaboration include an opportunity to engage U.S. scientists and students in a new international research collaboration. All U.S. members of the LADUMA team have strong records of supervising students, and all have appointments that will facilitate recruitment of students to the survey in the future. Half of the U.S. LADUMA team have affiliations with institutions that are part of the optical Southern African Large Telescope (SALT) partnership, strengthening the bonds that already exist between these institutions and South Africa and catalyzing new relationships among the collaborators. The partnership will also result in opportunities for education and outreach in S. Africa.

This award is being funded by NSF's Office of International Science and Engineering.

Project Report

Cutting-edge research efforts in modern astronomy increasingly involve large teams of scientists who work in many countries around the world. One of the challenges for any such team as it gets going is to establish strong, productive working relationships among its own widely scattered members and with other key stakeholders (e.g., the engineers responsible for designing and building a new telescope that the team will use). This project's main goal was to ensure that U.S. astronomers could be actively engaged in the early stages of a survey known as LADUMA ("Looking At the Distant Universe with the MeerKAT Array"), which has been approved for 5000 hours of observations with an array of 64 radio telescopes currently under construction in South Africa. LADUMA's main goal is to study the evolution of galaxies' neutral atomic hydrogen gas over the course of cosmic time, looking back from the present to when the universe was only a third of its present age. In January 2012, the LADUMA team held a weeklong "all hands" meeting in Cape Town, where one of the survey's principal investigators (PIs) is employed at the University of Cape Town and the MeerKAT engineering team is based. Thanks to NSF's support for this project, 10 U.S.-based members of the LADUMA team and two additional graduate students were able to attend the meeting in person. This was the first chance many of the astronomers involved in the survey had to meet each other or the engineers with whom they will be working closely over the next several years. Discussions in Cape Town focused on fleshing out the most exciting science analyses the LADUMA team will be able to pursue once MeerKAT starts producing data, and on identifying the key needs that must still be met (e.g., for software, theoretical modelling, and complementary data from other telescopes) if those analyses are to succeed. An important outcome of these discussions was a well-defined set of scientific and technical action items for different subsets of the team to tackle over the next year. On the final day of the meeting, a substantial fraction of the participants (including eight members of the U.S. delegation) split up to visit 17 high schools across the Cape Town area, where they spoke to over 2100 students about astronomy, the promise of MeerKAT, and the possible routes to scientific or technical careers. In the wake of the "all hands" meeting, unused funds were redirected to support two summer undergraduate research students-- one at Rutgers University working to understand the limitations of using images alone to estimate the distances to galaxies in the LADUMA target field, and one at the University of Wisconsin building up catalogs of interesting types of galaxies in the LADUMA field that will be worthy of study when (and before) MeerKAT starts taking data. Broader impacts of this project include the training in research of two undergraduate students; the introduction of two graduate students to the complexities of working with a large and diverse international scientific collaboration; and the strengthening of bonds among U.S. scientists, their scientific collaborators from other countries, and the South African engineers who are building MeerKAT and making it work. The strong engagement of U.S. astronomers in LADUMA also constitutes an American foothold in a science area that is a major driver for the even more powerful Square Kilometre Array (SKA) to be built over the next decade and shared between South Africa and Australia. The U.S.-based PI of LADUMA, Professor Andrew Baker of Rutgers University, thanks U.S. taxpayers for their support of this peer-reviewed project and invites anyone interested in learning more about the survey to visit www.facebook.com/MeerKATLaduma.

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Rutgers University
New Brunswick
United States
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