Astronomers have detected a new signal from mysterious objects most likely located outside the Milky Way galaxy. This is the first instance such a signal has been detected, that too from four different objects.
According to LiveScience, astronomers observed these four circular objects at radio wavelengths and found that they had bright edges. Usually, such circular observations have been known to represent astronomical objects like a supernova remnant, a planetary nebula, a circumstellar shell, a protoplanetary disc or even a star-forming galaxy.
But, scientists found nothing that would imply that these four circular features were like any of the astronomical objects previously observed. In their paper, astronomers have reported that these objects are part of a new class of the astronomical objects that have been named as odd radio circles or ORCs.
The astronomers mentioned in their paper, which is still under review by Nature Astronomy, “We have found an unexpected class of astronomical objects which have not previously been reported, in the Evolutionary Map of the Universe Pilot survey, using the Australian Square Kilometre Array Pathfinder telescope.”
All four ORCs were found to only be observable at radio wavelengths and didn’t show up on either the optical, infrared or X-ray wavelengths. But two of the ORCs were found to have a galaxy near their centre which was observed at optical wavelength.
The astronomers think that these ORCs can be “jets of a radio galaxy or blazar when seen end-on, down the “barrel” of the jet. Alternatively, they may represent some remnant of a previous outflow from a radio galaxy.” But again, no observations of this phenomenon was found to be similar to ORCs which have a bright edge and no signs of a visual blazar or radio galaxy at the centre.
Additionally, astronomers have also considered the possibility that these circular features might represent more than one astronomical object/phenomenon. But further work is required to study the nature of ORCs and find out more about these objects.
*Image for representation purpose only.