At the end of last year, researchers using Nasa’s Swift space observatory launched an investigation to study a group of mysterious radio sources first detected nearly six decades ago. For four months, team observed 21 bright radio sources from the revised Third Cambridge Catalogue, leading to the detection of ‘significant’ emissions for nine of them with the X-ray Telescope.

But, when using the spacecraft’s Ultraviolet/Optical Telescope, no sources could be found. These new observations support earlier assumptions that the source of these emissions may be ‘heavily obscured’ active galaxies. In the new study, led by Andrew Maselli of the Institute of Space Astrophysics and Cosmic Physics of Palermo, Italy, researchers used the Swift spacecraft to observe a group of 3CR radio sources between November 2014 and March 2015. READ MORE