Astronomers recently discovered a unique radio wave emitted from the direction of the heart of the Milky Way. The unique way in which the polarization of the waves rotates, as well as the variation in brightness, doesn’t closely match what the astronomers expect of other known celestial objects.
Published today in The Astrophysical Journal, the Astronomers have named the object responsible ASKAP J173608.2-321635, after its coordinates.
“This object was unique in that it started out invisible, became bright, faded away, and then reappeared. This behaviour was extraordinary.”Professor Tara Murphy
The international team of scientists behind the paper first discovered the object using the Commonwealth Scientific and Industrial Research Organizations (CSIRO’s) Australian Square Kilometer Array Pathfinder (ASKAP) telescope. The telescope array (which will be fully operational next year) makes use of 36 dish antennas 12 meters in diameter spread across a large area to increase the imaging capabilities.
“The strangest property of this new signal is that it is has a very high polarisation. This means its light oscillates in only one direction, but that direction rotates with time,” said Ziteng Wang, lead author of the new study.
Over the course of nine months in 2020, the teams observed six radio signals from the object, but were unable locate the source object in visible light.
The intermittent nature of the signal led the team to attempt to locate the object with a more sensitive telescope. The team used the MeerKAT radio telescope (the precursor to the Square Kilometer Array). Using the different equipment they located the single once again, but it was still intermittent,
Professor David Kaplan from the University of Wisconsin-Milwaukee, said, “The information we do have has some parallels with another emerging class of mysterious objects known as Galactic Centre Radio Transients [GCRT], including one dubbed the ‘cosmic burper.’”
But even these GCRTs are not well understood by scientists.
For now, this is another object in the space that is not yet understood.
The team notes in the paper that with how little time these emissions were detected, and the limited nature of sampling, suggests there could be other objects like this one in the field that simply haven’t been observed yet.
Hopefully future telescopes, such as the intercontinental Square Kilometer Array, will come online and provide additional more regular data to help understand this newly discovered object.
“We expect the power of this telescope will help us solve mysteries such as this latest discovery, but it will also open vast new swathes of the cosmos to exploration in the radio spectrum.”Professor Murphy