West Virginia undergrad makes discovery of possible new space object

William Atkins
Saturday, 29 September 2007 22:16

Science - Space

West Virginia University undergraduate student David Narkevic was looking at old radio data taken from an Australian radio telescope when he found something that looked like a very short and powerful burst of radio energy from a pulsar—but it wasn’t from a pulsar. So what is it?

While working with a team of five astronomers, headed by assistant professor of physics Duncan Lorimer of West Virginia University (WVU, Morgantown) and assistant astronomer the National Radio Astronomy Observatory (Socorro, New Mexico), Narkevic found this single blip (that lasted only about 5 milliseconds or 0.0005 second) within about 500 hours of old data recorded from the 21-foot Parkes radio telescope in Australia.

The radio burst was found by Narkevic near the irregular dwarf galaxy called the Small Magellanic Cloud—although it is located no where near this galaxy. It is one of two galaxies (the other being the Large Magellanic Cloud) that make up the Magellanic Clouds (one member of the Local Group of galaxies, of which the Milky Way is a member). The Small Magellanic Cloud is estimated to be 200,000 light-years from the Milky Way galaxy (where one light-year is the distance that light travels in vacuum over the course of one earth-year).

The results of Narkevic’s observations have been published in the September 27, 2007 online edition of Science magazine, which is called Science Express. Narkevic is a senior majoring in physics and political science. The other WVU team members are Matthew Bailes (Swinburne University, Australis), Maura McLaughlin (WVU and NRAO), and Fronefield Crawford (Franklin and Marshall College, Lancaster, Pennsylvania).

What makes this discovery very important is that the blip is not found on any other scans taken before or after the event that was observed by Narkevic. Two subsequent scans of the sky around the Narkevic blip did not show it either.

Initial analysis by the Lorimer team have determined that is it nothing that can be explained by already known astronomical phenomenon. It appears not to be a radio burst. The team thinks that the blip could be only about 1,000 miles (1,600 kilometers) across and around 3 billion light-years away—although these figures are preliminary and not yet verified.

Three billion light-years was determined to be its estimated distance away based on dispersion; or, the phenomenon that the phase velocity of a radiation wave, such as radio waves, depends on its frequency, which causes the separation of it into spectral components of different wavelengths. In the case of the blip, the higher frequencies of the signal arrived at the telescope before the lower frequencies arrived due to the radio waves passing through ionized gas while on its journey to Earth.

Currently, the Lorimer team is searching for other blips, which would help to verify the first discovery by Narkevic. They also want to discover the source of the blip. As quoted from the Sky & Telescope web article “Mystery Pulse from Outer Space”, the WVU astronomers are excited about the find, saying "The potential of [using] a population of radio bursts at cosmological distances to probe the ionized intergalactic medium is very exciting."

They have offered two theories about the event: According to the WVU website “WVU physics team discovers new phenomenon in universe,” Lorimer states, “This burst appears to have originated from the distant universe and may have been produced by an exotic event such as the collision of two neutron stars or the death throes of an evaporating black hole.”

McLaughlin, a team member and also an assistant professor of physics at WVU, said in the WVU article, “We’re actively looking for more of these powerful, short bursts in other archival pulsar surveys and hope to resolve the mystery of their origin. If we can associate these events with galaxies of known distance, the radio dispersion we measure can be used as a powerful new way to determine the amount of material in intergalactic space.”

Additional information is found at the National Radio Astronomy Observatory website titled “Powerful Radio Burst Indicates New Astronomical Phenomenon”.