Heading the Long Wavelength Array (LWA1) project for Virginia Tech is Steve Ellingson, associate professor with the Bradley Department of Electrical and Computer Engineering in the College of Engineering. Chris Wolfe of Chesterfield, Va., a doctoral student in electrical and computer engineering, designed part of the telescope and is developing an upgrade as part of his dissertation.
The roughly $10 million LWA1 is located on the Plains of San Agustin, which is also home to the National Radio Astronomy Observatory’s Very Large Array. “LWA1 is among the world’s most powerful telescopes operating at frequencies between 10 megahertz and 88 megahertz,” Ellingson said. The antennas are tent-shaped, with four wing-like sides attached to a vertical pole and a box on top that points skyward.
The telescope’s digital beamforming mode allows simultaneous observation in four independent directions, making it possible for four astronomers to use the telescope at the same time. In addition, LWA1 simultaneously produces high-sensitivity images of the entire sky every five seconds, Ellingson said. “The all-sky mode is not the ‘primary’ mode of the instrument, but it is what we show most often because most people can immediately understand what it is,” he added.
Astronomers and others will use LWA1 to study pulsars, Jupiter, the sun, and the earth’s ionosphere.
It is one of several telescopes worldwide in the race to detect the very weak broadband spectrum of the red-shifted 21-centimeter hydrogen line, which scientists expect will reveal details of the very early universe, as it existed before the first stars were formed. That race, of which Ellingson is a part, is known as the Large Aperture Experiment to Detect the Dark Ages, a collaboration with the University of New Mexico, Harvard University, and the University of California, Berkeley.
Also on deck for observation: A suspected class of powerful, but difficult to detect, intermittent astrophysical signals. Possible sources of these signals include giant flares from magnetars, exploding primordial black holes, and mergers of neutron stars in binary systems.
Discovering an exploding primordial black hole would be huge, said John Simonetti, professor and associate chairman of the physics department with the Virginia Tech College of Science, who will be listening for the distinct time-frequency signature of these events using LWA1. Physicists believe primordial black holes created in the Big Bang “evaporate” after a long period time, eventually self-annihilating in a final explosion which should be detectable by LWA1, he said.
Discovering such an event “would be an extremely exciting experience, it would confirm an idea of quantum gravity, the study of the physics of gravity,” Simonetti said.
Primordial black holes or not, astronomers say they are eager to use LWA1 to observe the universe in a frequency range that until now was neglected. “You see things you have never seen before, and we learn we know so little about the universe. We’re only scratching the surface of the universe, when we look out there,” Simonetti said.
Ellingson and Simonetti previously worked together with Cameron Patterson, also an associate professor of computer and electrical engineering, on a much smaller array radio telescope project, encompassing 24 dipole antennas, near Asheville, N.C. Competed in 2008, that project served as a technical pathfinder for LWA1, nearly 11 times larger in size. Patterson and Ellingson are co-advising Wolfe on the telescope project.
The LWA1 project began in 2007 as a collaborative effort between the University of New Mexico, Los Alamos National Laboratory, NASA’s Jet Propulsion Laboratory, the U.S. Naval Research Laboratory, and Virginia Tech. Funding came from NASA, the Office of Naval Research and the National Science Foundation. In December 2011, the project was designated as a University Radio Observatory by the National Science Foundation for the years 2012 to 2015, bringing a $1.5 million grant to support research efforts.
The Long Wavelength Array is a sensitive radio telescope operating in the frequency range of 10 megahertz to 88 megahertz and designed to observe in many directions simultaneously. This opens a new astronomical window on one of the most poorly explored regions of the electromagnetic spectrum, according to the project website.
Partners in the Long Wavelength Array project are:
The Long Wavelength Array, at a glance
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