What is something that is hundreds of billions of times more powerful than the Sun, and which repeatedly flashes with intense bursts of light, almost defying the laws of physics? No, it’s not your neighbors’ holiday lights that have broken down again. It’s a LFBOT in the depths of space.
LFBOTs (Luminous Fast Blue Optical Transit) are indeed very strange. They erupt with blue light, radio, X-ray, and optical emission, making them some of the brightest explosions ever seen in space, as luminous as supernovas. It is no exaggeration that it gives off more energy than hundreds of billions of stars like ours. They also tend to live quickly, burning for only minutes before burning out and fading into darkness.
LFBOTs are very rare, and in many cases their sources are unknown. But we’ve never seen anything as powerful as the LFBOT called AT2022tsd — also known as the “Tasmanian Devil.” Its strange behavior has been observed by 15 telescopes and observatories, including the WM Keck Observatory and NASA’s Chandra Space Telescope. Like other phenomena of its kind, it initially released incredible amounts of energy and then dimmed. Unlike any other LFBOT spotted before, this one appears to have come back from the dead. Caught again – again and again.
This is not a supernova
The most common transient extragalactic luminous events, i.e. flashes of light that rapidly develop and disappear, are supernovae. Their initial eruption is usually just weeks old. Not only did the Tasmanian Devil evolve faster than the supernova, but 14 individual flares were observed, lighting up over several months, or about a hundred days. Even near the end of the event, there was a single flare almost as bright as the original explosion of the transient. Scientists studying AT2022tsd still aren’t entirely sure whether they’ve accounted for every flare. It’s denser than another similar LFBOT that made headlines when it was discovered: AT2018cow, also known as “the cow.”
“The multi-wavelength properties of AT2022tsd are very similar to those of the cow-like transient AT2018…suggesting a common origin,” an international team of researchers said in a study recently published in the journal Nature.
AT2018cow displayed emissions similar to those of AT2022tsd (although not as strong). The “cow” could also be a reference to where these events get a lot of energy, as other similar transient beings are now thought to be possibly powered by a long-lasting energy source, although no such source has actually been found for any of the “cow” ” or “Tasmanian Devil” so far. This hypothetical source could be a compact object that continues to release massive amounts of energy through outflow or outflow. Some transients such as AT2018cow have been traced to magnetars or black holes that maintain Materials accumulate and are thus supplied with a continuous stream of energy.
Where I don’t know?
AT2022tsd’s eruptions must have come from something, and researchers are still trying to figure out why. Supermassive black holes are a tempting option because of the enormous amount of energy they produce. However, supermassive black holes also lurk at the centers of their galaxies. A closer look at the Tasmanian Devil and its location in its galaxy revealed that it was not close enough to the galactic core to be fed by a supermassive black hole. Although this hypothesis is considered unlikely, scientists believe that there are still other possibilities.
“Possible energy sources for the outflow are…a newborn neutron star or accretion on a stellar or intermediate-mass body,” they said in the same study. “In the latter case, the compact object could be a newly formed black hole with stellar mass.”
A stellar-mass black hole, intermediate-mass black hole, or neutron star likely unleashed a phenomenon wild enough to be called the Tasmanian Devil. The formation of LFBOT likely involved tidal disruption, which occurs when a star gets too close to a black hole and is torn apart by the black hole’s tidal forces. The tidal forces of neutron stars are also capable of disrupting stars. Devouring a star results in massive energy inputs and outputs to the black hole or neutron star, which may explain what sparked the Tasmanian Devil’s wrath.
Could At2022tsd change our understanding of physics? maybe. Both the enormous amount of energy they release and the shorter, long-lasting bursts test the limits of physics because so many bursts of light emitted over a short period of time would probably need to come from a relatively small source. But it is not clear how we will discover what this source is.
Nature, 2023. DOI: 10.1038/s41586-023-06673-6