Recent research indicates that modern gravitational wave detectors could be able to “listen” to the most powerful core-collapse supernovae at much greater distances than previously possible.It is estimated that the detectors could capture these events up to 65 million light-years away, well beyond the Milky Way, reaching up to the Virgo Cluster.
This capability would allow scientists to discover whether the dying massive star that generated the supernova left behind a black hole or a neutron star. Since the first detection of the subtle distortions in spacetime, known as gravitational waves, resulting from collisions and mergers between black holes and neutron stars, the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the United States, Virgo in Italy, and the Kamioka Gravitational Wave Detector (KAGRA) in Japan have opened a new window on the universe.
This innovative form of astronomy allows us to “listen” to some of the most violent and dramatic phenomena in the cosmos. The current generation of gravitational wave detectors, operating within the LIGO-Virgo-Kagra (LVK) collaboration, is designed to capture gravitational waves produced by supernova explosions marking the end of massive stars, followed by the formation of a black hole or a neutron star.
However, so far, they have not been able to detect the characteristic high-pitched “chirp” that should be heard during supernovae in our galaxy. According to the theory of general relativity formulated by Einstein in 1915, accelerating objects emit gravitational waves.
This means that, when black holes and stars approach each other, they emit low-frequency gravitational waves, which culminate in a high-pitched sound during the collision and merger, often resulting in a more massive black hole. Supernovae caused by the rapid collapse of the central core should also produce these gravitational wave emissions, but unlike mergers between dense stellar remnants, such as black holes and neutron stars, the signal produced by supernovae has not yet been detected. Maurice van Putten, from Sejong University, stated: “Considering the current capabilities of the LVK observatories and our calculations, we estimate that, under optimal conditions, about one event per year could be detected.” However, in a more conservative scenario, which takes into account less favorable conditions and the limited operational cycles of the detectors, a detection frequency of a few events per decade is expected. These numbers still represent a significant improvement compared to the two events per century estimated to occur within the Milky Way. The team focused on a particular type of core-collapse supernova, called Type-1c.
This type of supernova occurs when a massive star explodes after losing its outer layer of hydrogen and helium.
A subclass of these supernovae is particularly interesting, as the expansion of the expelled material is very rapid and associated with intense energy bursts called long gamma-ray bursts (GRB).
The final result of these explosions is likely a rapidly rotating black hole, surrounded by a huge “energy reservoir” in the form of angular momentum.
The angular momentum of these black holes is significantly higher than that of a neutron star formed by the same collapse process.
Our articles from Meteo Giornale are on Google News, follow us for free!
Follow our feed
