A wandering black hole wanders in the Milky Way: it is located 5,000 light years from us and is the first solitary black hole to have ever been "observed", although its existence had been hypothesized for some time.
To "capture" it for the first time was a network of observatories on Earth and the Hubble Space Telescope thanks to the work of a hundred researchers, including some from the University of Salerno, the National Institute of Nuclear Physics (Infn), Sapienza di Roma and the National Institute of Astrophysics (Inaf), coordinated by the Space Telescope Science Institute in Baltimore whose results have been published on the arXiv platform and submitted to the Astrophysical Journal.
Being the remnants of ancient large stars, it is estimated that the number of black holes in our galaxy is very high, several million. But observing these very small and incredibly "heavy" objects is by their very nature an almost impossible challenge, as they do not emit any form of light or radiation.
The only black holes identified so far had been seen indirectly, only when a companion star was present near them or by noticing the "anomalous" behavior of gas clouds attracted by their gravitational field. Now for the first time a hole has been observed “solitary” black, that is, with nothing around.
The discovery comes from a very long work of comparing data collected over years by a network of telescopes on millions of stars to look for traces of "microlensing" effects, ie anomalies in the brightness of distant stars due to transit (between us and the source of distant light) of some very large mass.
Among the approximately 2,000 anomalies observed each year, researchers are sure to have recognized the signature of a black hole: an object with a mass 7 times that of the Sun, just over 5,000 light-years away in the direction of the galactic center, and in rapid displacement, 45 kilometers per second.
(Unioneonline / vl)
