It could be a “kilonova”, the merger event analyzed by a team of researchers, as revealed in a statement from Northwestern University. Codenamed GW170817, the event was investigated by a team of researchers who discovered what is the afterglow of the merger that is believed to have occurred between two neutron stars, two hyperdense bodies.
X-ray detection of a melting event
Specifically, the researchers identified the X-rays generated by the meltdown event, which blew away numerous debris and various materials that expanded, generating a sonic “boom.”
Scientists are not 100% sure of the nature of this emission: it could be, even if it is a minor hypothesis, the fall of a large quantity of matter in a black hole, itself formed by the merger of two neutron stars. In this sense, the announcement is still “provisional”.
An “uncharted territory”
As Aprajita Hajela, an astrophysicist at Northwestern’s Center for Interdisciplinary Research and Exploration in Astrophysics (CIERA) and one of the study’s authors, explains, this is “uncharted territory.” Neutron star mergers are not an everyday occurrence, and when a merger is intercepted, the opportunity to understand these still somewhat mysterious phenomena is extraordinary.
Event intercepted for the first time in 2017
Neutron star merger events have been intercepted in the past. This same event was already intercepted on August 17, 2017. It is precisely from this area that the researchers discovered the emission of gravitational waves, real ripples in space-time. The researchers who carried out this new study reanalyzed the data, in particular the X-ray data collected by NASA’s Chandra Space Telescope. The researchers initially stopped collecting data in 2018, but Hajela’s team suggests that the decline in brightness didn’t actually stop until 2020, with X-ray emissions being unusually constant.
New hypotheses are likely needed to explain the strange emissions
According to one of the lead authors of the study, astrophysicist from the University of California at Berkeley Raffaella Margutti, to explain these X-ray emissions, it is probably necessary to hypothesize a new type of source, different from those previously discovered or supposed. In this sense, new studies should also be carried out to understand if it is really a kilonova.
What is a kilonova
A kilonova is a particular emission of powerful electromagnetic radiation caused in particular by the radioactive disintegration of the heavy nuclei of two neutron stars or of a neutron star and a black hole when they merge. The first kilonova was not discovered until 2008, when scientists detected a short-lived gamma-ray burst.