Star Search
WV High School Students Discover Pulsars
Astronomical discoveries aren’t exactly rare at the giant Robert C. Byrd Green Bank Telescope at the National Radio Astronomy Observatory (NRAO) at Green Bank, W.Va. With a reflecting dish that measures 100 meters (328 feet) in diameter, the Green Bank Telescope is the largest fully steerable radio telescope in the world. As such, it provides astronomers an unequalled opportunity to explore and understand the heavens.
But it’s not every day that significant astronomical discoveries are credited to high school students. Yet that’s exactly what happened when West Virginia students were given an opportunity to analyze data gathered by the big telescope.
Lucas Bolyard, a sophomore at South Harrison High School in Clarksburg, and Shay Bloxton, a sophomore at Nicholas County High School in Summersville, each have been credited with discovering a pulsar – a rotating, super-dense neutron star.
The story behind the two students’ remarkable achievements began in the summer of 2007 when the giant telescope underwent a major track renovation. One of the largest moving structures anywhere on land, the telescope weighs more than 16.7 million pounds. That rolling weight pushed the limits of the telescope’s steel track beyond its design capabilities. After a two-year design and manufacturing process, a track replacement project was slated.
That work meant severely limiting the operation of the telescope, perhaps even shutting it down completely, for as long as four months. However, working with astronomers Maura McLaughlin and Duncan Lorimer at West Virginia University, NRAO staff scientists and engineers developed a program that would allow the telescope to continue to take data with minimal movement as the sky passed overhead.
The result was approximately 120 terabytes of data collected from about 35 percent of the visible sky while utilizing receivers specifically designed to detect the super-dense neutron stars called pulsars and transient astronomical radio signals called rotating radio transients.
Fully analyzing all the data collected is a daunting task that will require years of computing time. However, NRAO Education Officer Sue Ann Heatherly saw this as an opportunity to give West Virginia high school students the ability to become radio astronomy researchers through first-hand experience with real scientific data.
Thus, some of the data taken during the track replacement project was set aside for students and the Pulsar Search Collaboratory (PSC) was born.
Funded by a grant from the National Science Foundation, the PSC is a joint effort between NRAO and WVU. The goal is to interest students in science, technology, engineering and mathematics (STEM) related careers through scientific research using radio astronomy data. The PSC, led by Heatherly and Project Director Rachel Rosen, includes training for teachers and student leaders, and provides parcels of data from the Green Bank Telescope to student teams. Some 300 hours of the observing data were reserved for analysis by the student teams.
The teams use specially designed analysis software to reveal evidence of pulsars. Each portion of the data is analyzed by multiple teams. In addition to learning to use the analysis software, the students also must learn to recognize man-made radio interference that contaminates the data. The project will continue through 2011.
"The students get to actually look through data that has never been looked through before," Rosen said. From the training, she added, "the students get a wonderful grasp of what they’re looking at, and they understand the science behind the plots that they’re looking at."
The data is part of a survey to detect two types of astronomical objects: pulsars and rotating radio transients. Pulsars, super-dense neutron stars with large magnetic fields, are known for their lighthouse-like beams of radio waves that sweep through space as the neutron star rotates, creating a pulse as the beam sweeps by a radio telescope. Pulsars are the corpses of massive stars that exploded as supernovae. Rotating radio transients (RRATs) are thought to be similar to pulsars except that while pulsars emit these radio waves continuously, rotating radio transients emit only sporadically, one burst at a time, with as much as several hours between bursts. Because of this, they are difficult to discover and observe, with the first one only discovered in 2006.
"These objects are very interesting, both by themselves and for what they tell us about neutron stars and supernovae," McLaughlin said. "We don’t know what makes them different from pulsars – why they turn on and off. If we answer that question, it’s likely to tell us something new about the environments of pulsars and how their radio waves are generated. They also tell us there are more neutron stars than we knew about before, and that means there are more supernova explosions. In fact, we now almost have more neutron stars than can be accounted for by the supernovae we can detect."
When two of the high school students started plowing through the data given them, they each made an exciting discovery.
The first student, Lucas Bolyard, made his discovery in March 2009, after he already had studied more than 2,000 data plots from the Green Bank Telescope and found nothing.
"I was home on a weekend and had nothing to do, so I decided to look at some more plots from the GBT," he said. "I saw a plot with a pulse, but there was a lot of radio interference, too. The pulse almost got dismissed as interference."
Nonetheless, he reported it, and it went on a list of candidates for WVU astronomers McLaughlin and Lorimer to re-examine, scheduling new observations of the region of sky from which the pulse came. Disappointingly, the follow-up observations showed nothing, indicating that the object was not a normal pulsar. However, the astronomers explained to Bolyard that his pulse still might have come from a rotating radio transient.
Confirmation didn’t come until July. Bolyard was at the observatory with fellow PSC students. The night before, the group had been observing with the GBT in the wee hours, and all were very tired. Then Lorimer showed Bolyard a new plot of his pulse, reprocessed from raw data, indicating that it is real, not interference, and that Bolyard is likely the discoverer of one of only about 30 radio transients known.
Suddenly, Bolyard said, he wasn’t tired anymore. "That news made me full of energy," he exclaimed. His discovery fueled enough excitement for the student to be a guest of honor at the White House star party on October 7, 2009.
President Obama, in his opening remarks at the star party, introduced Bolyard, who stood next to the podium as the president said:
"And earlier this year, Lucas Bolyard ... A high school sophomore from West Virginia, discovered some unusual data that turned out to be an extremely rare kind of star called a pulsar. And Lucas was explaining to me just what a pulsar was so that I wasn’t embarrassed when I came out here."
The second student, Shay Bloxton, spotted evidence of a pulsar on October 15. Bloxton, along with NRAO astronomers observed the object again one month later. The new observation confirmed that the object is a pulsar.
"I was very excited when I found out I had actually made a discovery," Bloxton said. She went to Green Bank in November to participate in the follow-up observation. She termed that visit "a great experience. It also helped me learn a lot about how observations with the GBT are actually done."
For at least these two students, the PSC has brought to life the excitement of discovery. "Science is a lot more exciting for me now that I’ve made this discovery," Bolyard said. Scientific research, he learned, "is a lot of hard work, but it’s worth it!"
A year ago, he said, he wouldn’t have thought of astronomy as a career, but the experience of discovery made astronomy at least a possibility for him. However, he added, "I’m still hoping to be a doctor."
For Bloxton, the pulsar discovery may be only her first in a scientific career. “Participating in the PSC has definitely encouraged me to pursue my dream of being an astrophysicist,” she said, adding that she hopes to attend West Virginia University to study astrophysics.
Michael Holstine is the business manager at the National Radio Astronomy Observatory (NARO) in Green Bank, W. Va., where he manages facility operations and has been the project manager for construction at the site for the last 18 years. Originally from Campbells Creek near Charleston, W. Va., he attended the U.S. Naval Academy and is a 1980 graduate of West Virginia Institute of Technology with a degree in civil engineering. He is a registered Professional Engineer.
