Milan, November 17th. (Askanews) – The merger of two black holes as a result of a head-on collision, and thus not preceded by the typical spiral spiral found in the direction of signals detected so far by gravitational interferometers, could be one way in which these violent astrophysical phenomena occur. This is supported by a study conducted by a group of researchers from the university and the INFN department in Turin, together with colleagues from the Friedrich Schiller-University (FSU) in Jena (Germany), published today, Thursday, November 17 in the journal Nature. astronomy.
Through computer simulations, scientists have confirmed that the model predicting the existence of binary systems made up of pairs of long-orbiting holes, capable of fast and precise collisions, is consistent with the short-lived anomaly observed by the two. The American LIGO and European Virgo interferometers, hosted in Italy, at the European Gravity Observatory EGO founded by INFN and the French Center for Scientific Research. If confirmed, the result could provide a new tool for interpreting gravitational signals, and further understanding of the configurations that characterize binary black hole systems.
Observed for the first time in 2015, gravitational waves, imperceptible perturbations in space-time, are able to provide us with valuable information about the celestial bodies that make up the binary systems responsible for their emission, as well as about the dynamic evolution of these same systems. In the case of black holes, the gravitational signals detected so far have matched predictions from the model used to interpret them, which characterize three different phases in the merger process: initial, characterized by the black holes’ spiraling orbit around each other (inspiral); merger-related centralization (merger); and final, as the newly created celestial body expands and contracts before settling down (the ring).
“The analysis of a specific signal recorded on May 21, 2019 by the LIGO and Virgo collaboration showed some differences compared to the data we are used to working with. The shape and brevity of the signal associated with the event — less than a tenth of a second — actually leads us to hypothesize an instantaneous merger of two holes, which occurred in Absence of an upward phase ”, comments Alessandro Nagar, researcher at the INFN department in Turin.
The event is called GW190521, which could be the product of the merger of two generations of black holes, since their masses, equal to about 85 and 60 solar masses, would theoretically not be allowed as a result of a stellar collapse, so it was the subject of careful investigation by the scientific community that proposed alternative hypotheses. to explain its origin. “GW190521 – explains Rossella Gamba, researcher at the University of Jena and lead author of the paper – a particularly mysterious signal because its shape and explosive nature make it very different from what we have observed in the past.”
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