An article published in “The Astrophysical Journal” reports a study on a double X-ray source in the early universe cataloged as MG B2016+112 which could be composed of two supermassive black holes whose image is distorted by a gravitational lens. Cristiana Spingola, Daniel Schwartz, and Anna Barnacka started from a survey obtained by NASA’s Chandra X-ray Observatory to examine the double object observed. This is an unprecedented situation because from the Earth we see it as it was when the universe was about two billion years old with the two components separated by only 650 light-years. At present, it cannot be ruled out that it’s a single supermassive black hole and one of its jets of materials whose image was strongly distorted by the gravitational lens.
The story of what was interpreted as a double active galactic nucleus cataloged as MG B2016+112 begins on April 12, 2000, when the Chandra X-ray Observatory detected 24 photons over the course of just over two hours of observation. They reached Chandra after a not-so-smooth ride in the sense that there was a galaxy in their way whose gravity deflected them.
Chandra’s detection remained on archive but new observations of the same area were conducted on February 25, 2002, and July 2, 2016, with the VLBA (Very Long Baseline Array) radio telescope network, which collected radio emissions from the MG B2016+112 source. Again, those were distorted emissions from the gravitational lens.
Thanks to these observations, in an article published in September 2019 in the journal “Astronomy & Astrophysics” a team led by Cristiana Spingola hypothesized that MG B2016+112 was a system with two supermassive black holes. The examination of the various X-ray and radio wave detections continued together with Daniel Schwartz and Anna Barnacka and the conclusion is a confirmation that the source is the same in all the observations.
That’s not a foregone conclusion due to the limitations of X-ray detections and the distortion caused by the gravitational lens. The image (Illustration: NASA/CXC/M. Weiss; X-ray (inset): NASA/CXC/SAO/D. Schwartz et al.) shows Chandra’s detection, which in the illustration of their path indicates how the image of one of the components of MG B2016+112 was duplicated by a galaxy’s gravitational action.
The analysis of the data shows a situation consistent with two supermassive black holes nearly 12 billion light-years away from Earth. This means that they are in the early universe, as we see them from Earth as they were when the universe was about two billion years old. This is the first X-ray detection from objects at such a distance that at the same time are so close, as they’re just about 650 light-years apart.
It’s not possible to completely rule out the possibility that MG B2016+112 is composed of a single supermassive black hole and a jet of materials emitted from it. However, the analysis of the characteristics of this source makes this possibility very unlikely.
New observations with the Chandra Space Observatory of a much longer duration than those conducted in 2000 could bring better detections useful to obtain certainties on the nature of MG B2016+112 and on its characteristics. Better-quality detections in other bands of the electromagnetic spectrum may require next-generation instruments.
Solving the scientific mystery of MG B2016+112 for good would have some ramifications linked to cosmological research of various types in addition to the advances in the exploitation of gravitational lenses for the observation of very distant objects. There’s a lot of research on primordial supermassive black holes trying to understand how they formed relatively quickly. If it were ascertained that there are two supermassive black holes, their proximity could produce gravitational waves that could be detected by new-generation instruments now in the design stage. In short, the studies of this object will continue and could offer more interesting results.
