We may know a little more about these strange types of cosmic explosions than we thought.
They are known as Fast Luminous Blue Optical Transients, or LFBOTs, and one of them is named Finch (AT2023fhn) is observed in intergalactic space, at great distances from nearby galaxies.
This is a problem, because astronomers think the LFBOT could be a type of massive supernova – something that is thought to only occur within galaxies.
“The more we learn about LFBOT, the more it surprises us.” said astronomer Ashley Krems European Space Agency and Radboud University in the Netherlands.
“We have now shown that LFBOTs can occur at great distances from nearby galaxies, and Finch’s location is not what we would expect for a supernova.”
The first LFBOT was spotted in 2018, and since then we’ve seen quite a few of them. With each new discovery, LFBOT continues to baffle scientists. This space explosion was very bright – at least 10 times brighter than a normal supernova – and very short.
Ordinary supernovae tend to flare up to a peak, then dissipate within a few weeks or months; LFBOT is like a camera flash in space. And it’s very hot. This is what gives it the bluish color.
Artist’s impression of the AT2023fhn, also known as The Finch. (NASA, ESA, NSF NOIRLab, M. Garlick, M. Zamani)
Scientists think the event may have been caused by an unusual type of supernova collapse, where the core of a dying star collapses directly into a neutron star or black hole. This requires a massive progenitor star, At least eight times the mass of the Sun.
Another possibility is that the flash may have been caused by a black hole devouring another ultra-dense object, such as an object White dwarf star.
Massive stars don’t live long The main sequence Spirit. That Less than 100 million years ago A star with a mass eight times the mass of the Sun. They are born in areas very rich in dense gas and dust, which means galaxies. there There is not much matter in intergalactic space.
Although some stars can be knocked out of their orbits onto escape paths and out of their host galaxies, the progenitors of massive neutron stars and black holes are not expected to make it that far before a supernova eventually appears.
In fact, all previous LFBOTs were found in the spiral arms of galaxies where star formation occurs, which is thought to be the site of supernovae.
This brings us to the Finch problem. Discovered by the Zwicky Transient Facility on April 10, 2023. Its temperature was measured at 20,000 degrees Celsius (approximately 36,000 Fahrenheit). Hubble was then called in to find out the source. This is where things start to get a little weird.
The explosion occurred about 2.86 billion light years away, but in intergalactic space, about 50,000 light years from the nearest spiral galaxy, and 15,000 light years from the spiral galaxy’s nearest dwarf galaxy. This poses a major challenge to the supernova hypothesis.
Hubble image of a finch. (NASA, ESA, STScI, A.Krems/Universitas Radboud)
However, the black hole hypothesis is still being debated. Researchers say it is possible that an ancient and isolated ball of stars known as a globular cluster is hiding in intergalactic space.
Globular clusters are thought to be full of black holes, a rarely seen group of intermediate masses. If there are globular clusters out there, too faint to see, we may have caught one of these black holes feeding uncontrollably.
Another possibility is that the explosion was the result of a collision between two neutron stars, one of which was a magnetar, whose strong magnetic field could have strengthened the resulting kilonova. A theoretical analysis needs to be performed to determine the plausibility of this scenario.
“This discovery raises more questions than it answers.” Kata Cream. “Further research is needed to find out which of several possible explanations is correct.”
But one thing is certain. The more of these things we discover, the stranger they become.
This research was accepted at Monthly Notices Letters of the Royal Astronomical Societyand available at arXiv.
2023-10-07 20:53:33
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