Astronomers that observed 21 radio sources from outer space using NASA’s space observatory have made a shocking discovery. Out of the 21 radio sources that researchers analysed, four cases exhibit anomalous characteristics.
Astronomers led by Andrea Masseli of the Institute of Space Astrophysics and Cosmic Physics of Palermo, Italy, undertook an observational campaign to study and analyse a group of unassociated radio sources using NASA’S Swift Space Observatory. They found that some of the radio sources CANNOT be determined, suggesting they may originate from a source that is currently ‘invisible’ to us.
NASA’s Swift spacecraft explores our universe in gamma rays, X-rays, ultraviolet, and optical wavebands. It is a very useful tool that allows astronomers to analyse electromagnetic events from outer space.
The Swift space observatory carried out the first sensitive hard X-Ray survey of the skies.
Experts used it for a period of four months as they followed closely 21 bright radio sources from the Third Cambridge Catalogue, which allowed the detection of ‘significant’ emissions for nine of them using the X-Ray telescope.
According to the study published in arXiv, researchers wrote: “The extragalactic subset of the revised Third Cambridge Catalogue (3CR) of radio sources has a long history as one of the fundamental samples used to understand the nature and evolution of powerful radio galaxies and quasars, as well as their relationship to their host galaxies and environments on parsec through megaparsec scales.”
In order to understand the radio sources, astronomers utilised the X-ray Telescope (XRT) and the Ultraviolet/Optical Telescope (UVOT) aboard the Swift space observatory.
The discovery proved to be fascinating.
Astronomers indicate that nine of the radio sources display prominent emissions in the soft X-Ray band.
Interestingly, for each of the radio sources, and four others that did not have a soft X-Ray association, astronomers managed to assign an infrared equivalent in the (AllWISE) All Wide-field Infrared Survey Explorer catalogue. However, researchers were unable to find an optical/ultraviolet counterpart utilising the UVOT.
Okay, so what does this exactly mean?
Well, in this case, a mystery leads towards more mysteries… sort of.
Astronomers have explained that these radio emissions originate from something we may not be able to observe, or in this case, from a group of ‘active galaxies’ that are obscured from our view.
Researchers further explained: “It is worth mentioning that no optical/UV counterpart has been detected in the UVOT filters at the position of the 21 NVSS sources: this is in agreement with the notes reported in the 3CR catalogue in which the large fraction of these 3CR unidentified radio sources were classified as obscured active galaxies.”
However, researchers warn it’s too early to conclude for sure and that in order to get to the bottom of the mystery and what’s truly out there, pectroscopic analysis in the infrared range will be needed to accurately determine the nature of the radio sources.