An astrophysical mystery solved long 50 years thanks to the space telescope Ixpe of NASA and the Italian Space Agency: through its ‘eyes’ it was possible to observe the X-rays emitted by the binary system like never before Cygnus X-3discovering that its particular light it’s the one that he arrives to us after being reflected from a wall of matter falling into black hole of the same binary system. The results of the study are published in the journal Nature Astronomy by an international research team in which Italy participates with Asi, the National Institute of Astrophysics, the National Institute of Nuclear Physics and the University of Roma Tre.
Since the early 1970s, the Cygnus X-3 binary system has been known to become very bright in the radio bandexcept then fade in a few days. This peculiar characteristic stimulated scientists from all over the world to carry out the first coordinated astronomical investigations.
The turning point came with the Ixpe satellite, created by NASA and ASI with the contribution of Inaf, Infn and Ohb-Italia. According to Alexandra Veledina, a researcher at Finland’s University of Turku and lead author of the study, the use of polarization in X-rays provided crucial information about the geometry of the material near the central black hole. “We found that the compact object is surrounded by a shell of dense and opaque matter“, explains Veledina. “The light we observe is a reflex from the inner walls of a cup-like funnel with l‘mirrored interior“.
This discovery led to classification of Cygnus X-3 as an ultra-bright X-ray source (Ulx): the source it can quickly swallow so much gas That a part of this it is not captured by the black holebut is instead expelled from the system itself.
“The dense and opaque matter that leads to such a high polarization in Cygnus X-3 unique”.
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