We may know much less about a freak cosmic explosion than we thought.
They are called luminescent fast blue optical transients, or LFBOTs, and one Finch (AT2023fhn) observed in interstellar space at considerable distances from the nearest galaxy.
That’s a problem, because astronomers thought LFBOTs might be a type of massive supernova — something that actually happened within the confines of a galaxy.
“The more we learn about LFPODs, the more they surprise us.” Astronomer Ashley Grimes says European Space Agency and Radbot University in the Netherlands.
“We have now shown that LFPODs can occur far away from their nearest galaxy, and Finch’s location is not what we would expect for a supernova.”
The first LFBOT was discovered in 2018, and since then we’ve discovered quite a few. With each new discovery, LFBOTs continue to puzzle scientists. These space explosions are very bright – at least 10 times brighter than a normal supernova – and very brief.
Normal supernovae peak and fade over weeks or months; LFBOTs are like camera flashes in space. And they are very hot; That’s what gives them their blue color.
Scientists thought these events might be caused by an unusual type of core-collapse supernova, in which the core of a dying star collapses directly into a neutron star or black hole. This requires a large progenitor star, At least eight times the mass of the Sun.
Another possibility is that the flashes could be caused by the black hole swallowing another ultradense object. A white dwarf star.
Big stars don’t live long Main sequence Lives. Its Less than 100 million years A star has eight times the mass of the Sun. And they were born in regions of dense gas and dust, namely galaxies. It’s there Not much in intergalactic space.
Although some stars can exit the orbit and exit the velocities of their host galaxies, massive neutron star and black hole progenitors are not expected to get that far before their final supernovae.
In fact, all previous LFBOTs have been found in the spiral arms of galaxies where star formation is occurring—the place where one would expect to find a supernova.
This brings us to Finch’s problem. It was detected by the Zwicky Transient Facility on 10 April 2023. Its temperature has been measured at 20,000 degrees Celsius (about 36,000 Fahrenheit). Hubble was called in to find out where it came from. This is where things started to go a little slow.
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 that spiral galaxy’s nearest dwarf satellite galaxy. This poses a significant challenge to the supernova hypothesis.
But the black hole hypothesis is still on the table. Researchers say it’s possible that an old, isolated ball of stars, called a globular cluster, is lurking in intergalactic space.
Globular clusters are thought to be entangled with black holes, a rare intermediate mass type. If there is a globular cluster out there, too faint to see, we may have blindly snacked on one of these black holes.
Another possibility is that the explosion was caused by a collision between two neutron stars, one of which may have been a magnet, whose intense magnetic field could have amplified the resulting kilonova. Theoretical analysis should be performed to determine the plausibility of this scenario.
“The finding raises more questions than it answers.” Crimes say. “More work is needed to determine which of the many possible explanations is correct.”
One thing is certain though. The more we discover these things, the weirder they are.
The research was accepted Monthly Notices of Letters of the Royal Astronomical Societyand available arXiv.