Posted: Apr 22 2014 9:41 AM By Kieran Dickson
Astronomers Have Detected Mysterious Intergalactic Radio Bursts, Again
A short yet powerful burst of radio waves has been detected deep in outer space by a team of astronomers at the Arecibo Observatory in Puerto Rico, leading to an array of theories about what's behind it. The huge 3 millisecond spike in radio waves is being likened to mysterious readings that came out of Australia in 2011 and 2012, which researchers believed to have originated from outside our galaxy.
When a series of radio bursts were detected by the Parkes radio telescope in Australia in 2011 and 2012, they were short and repetitive in nature. This repetition led to the theory that the spike in radio activity was attributed to a blitzar, a proposed astronomical phenomenon that occurs when a neutron star fails to develop into a black hole. However, the astronomical community has failed to draw an agreed upon conclusion with other explanations ranging from deteriorating black holes to supernova gamma ray bursts.
While a cause for the radio bursts seen by observatories such as Arecibo and Parkes has not been easy to nail down, with each new detection scientists are able to better understand roughly where they are originating from. In most cases, the consensus seems to be that the origin of these radio waves is billions of light years away, meaning that it is highly likely we are receiving radio waves from another galaxy.
Researchers are able to get an idea on how far away these waves originated using a measurement called dispersion.
"Normally, radio waves travel at the speed of light. This means that all the different wavelengths and frequencies of radio waves emitted by the same object - say, a pulsar - should arrive on Earth in one big batch," says Nat Geo's Nadia Drake.
"But if something is sufficiently far away, that changes. Longer, lower frequency waves traveling through the cosmos have a trickier time getting to Earth. Clouds of ionized interstellar particles - electrons, primarily - form roadblocks that slow and redirect these longer waves, causing them to follow a more sinuous path. As a result, the longer waves arrive just a bit later than their shorter kin - sometimes the difference is only a fraction of a second."
In the case of these latest readings, it is the conclusion of the study's authors that the radio burst detected at the Arecibo Observatory are intergalactic in nature.
"Recent work has exploited pulsar survey data to identify temporally isolated millisecond-duration radio bursts with large dispersion measures (DM)," reads the draft study. "These bursts have been interpreted as arising from a population of extragalactic sources, in which case they would provide unprecedented opportunities for probing the intergalactic medium; they may also be linked to new source classes."
The longer gap between bursts recorded at Arecibo not only lead to a conclusion that they originated a long, long way away, but they also suggest that they will not be so easily categorized as originating from previously theorized phenomenon such as pulsars or blitzars, both of which demonstrate bursts in quick succession of each other.
So it would seem that something outside of our galaxy is pumping high energy radio waves our way, quite what it is though, is another matter entirely. However, with more readings expected to come into the Parkes Telescope in New South Wales, Australia, and a host of other telescopes being looked at, it may not be long until we starting uncovering the mystery of these mysterious intergalactic radio waves.
A digital copy of the study is available below: