New Executive Director for Long Wavelength Array Prepares to Build a Major Astronomy Research Instrument

UNM Today : Astrophysicist Lee J. Rickard will direct the assembly and testing of the Long Wavelength Array for the University of New Mexico. Rickard is following up on work he did with the Remote Sensing Division of the Naval Research Laboratory at the Very Large Array near Socorro, N.M. in the early 1990’s.

At that time his research group was working to determine whether the “noise” in the ionosphere could be filtered out well enough to do productive research in the lower frequencies of the radio spectrum. Initial results showed it probably can and a new area of scientific research began.

The Long Wavelength Array is a radio telescope designed to allow researchers a way to detect radio waves in the radio frequency range of 10 - 80 MHz passing through the ionosphere. The ionosphere is a part of the atmosphere that begins about 25 miles above the earth and extends outward hundreds of miles. It contains charged particles that allow lower frequency radio waves to be transmitted great distances and has its own ‘weather’ that can disrupt communications and navigation systems.

The initial demonstration instrument, the Long Wavelength Demonstrator Array, is already in place at the VLA in Socorro. It was funded by the Naval Research Laboratory and built by the Applied Research Laboratories of the University of Texas.

Rickard is now searching for sites in southwestern New Mexico for the next 16 instruments. Combined, they will act as a single receiver to give much greater focus and clarity to faint signals.

Opportunities for StudentsAs the LWA is designed and built, it will offer an unusual opportunity for undergraduate and graduate students to become involved in constructing and operating a major astronomical instrument. Rickard says “the kind of electronics we put on the antennas and use for receivers are the sorts of things that students can put together in a laboratory. So what we are looking at is an opportunity to do radio astronomy in a way that students can get a lot more engagement with than they can with the other big facilities.”

At UNM that means working with one of the professors involved with the project. In the Physics and Astronomy Department associate professor Greg Taylor, http://www.phys.unm.edu/~gbtaylor/ , professor Jack McIver, who is also Senior Associate Vice President for Research and Economic Development, associate professor Patricia Henning, assistant professor Ylva Pihlstrom http://www.phys.unm.edu/~ylva/ and adjunct professors John Dickel and Helene Dickel are all working in some area of the project. Civil Engineering professor Walter Gerstle is involved in engineering aspects, and electrical engineering associate research professor Christopher Watts http://www.ece.unm.edu/~cwatts/ is working on ionospheric studies.

Genesis of an Idea

This project began as an idea in the astrophysics community more than 15 years ago when researchers at the Naval Research Laboratory decided to follow up work by University of Maryland professor Bill Erickson, whose Clark Lake telescope imaged low frequency waves in the radio spectrum. They put a test dipole on the VLA which showed them that a large part of the “noise” in the ionosphere could be filtered enough to warrant a closer look with better instrumentation.

Rickard and other researchers at the NRL proposed a major project through the decadal process at the National Academy of Sciences. That is essentially a strategic planning effort run by the National Research Council to decide what big areas of research warrant major spending by the U.S. Government. The idea was approved and the Long Wavelength Array was launched. That meant the research community backed the idea, and that several institutions were prepared to cooperate in the research.

Three major efforts are now underway to study the ionosphere worldwide. The effort in New Mexico is led by the Southwest Consortium, which includes the University of New Mexico, Los Alamos National Laboratory, the University of Texas at Austin, the Naval Research Laboratory and Virginia Tech.

Project TimelineRickard is now searching for 16 sites in southwestern New Mexico he can use to construct the initial arrays of instruments. Each site will hold several hundred dipoles, which in concert will be used to better focus the available information. Site selection is ongoing, but he plans to have the first site online by the end of 2008 to complete Phase I of the project.

Phase II, expected to last through 2010 will bring another six or seven stations to completion. In Phase III and IV, the remaining stations will be completed and the entire initial project is expected to be running by 2014. But the partially built telescope should be able to do important scientific work even at the earliest construction phases.

If the information provided by the initial array is worthwhile, Rickard says the project may eventually expand to include 50 arrays.

Science Focus

The LWA will have several jobs. Perhaps most important is gaining an understanding of ionospheric ‘weather’ which can disrupt navigation systems like GPS, military communications systems and a variety of other commercial and defense systems.

Researchers will use it to search for the faint and distant traces from the beginning of the universe; to study the distribution of cosmic rays in the Milky Way Galaxy and to search for planets in other solar systems. The system is so flexible that it will allow them to search for transient objects such as gamma ray bursts and study the effects of solar and space weather on the earth.

More information about the LWA is available at Long Wavelength Array.