Cow became ten times brighter than a typical supernova, which is one of the most powerful explosions that exist. This is the research around this mysterious space phenomenon.
We put you on record: on June 16, 2018, a brilliant star explosion – completely different from what had been seen before – was unleashed in the skies, quickly capturing the attention of astronomers around the world.
The peculiar event was first seen by the ATLAS service in Hawaii, whose scientists dubbed it AT2018cow through a random name system. It would not take long to earn the nickname of ‘cow’ (cow, in English). Reasons were not lacking for such media success: just three days after the explosion, Cow had become ten times brighter than a typical supernova, which is one of the most powerful explosions that exist, announcement of the death of a massive star.
Therefore, the experts are completely lost in this new phenomenon. “We still do not know what this is, although it is one of the most studied cosmic events in history,” says Anna Ho, a graduate of Caltech and lead author of a study on the event. She argues that Cow was probably a supernova, but other scientists have proposed that it could have been caused by a black hole that destroyed a type of star called white dwarf.
In any case, and thanks to the technology that we explain below, astronomers believe that this is the first time that a newborn compact object is seen in real time, like a black hole, that shines brightly in X-rays. that, because it is embedded in the ejection of the supernova explosion, the engine would normally be hidden from view … at least until now.
How was the ‘cow’ studied?
Hours, days and weeks after the event, the terrestrial and space telescopes were set on Cow, observing a dramatic increase in brightness across the electromagnetic spectrum, from high-energy X-rays to low-energy radio waves.
Specifically, Ho and his colleagues observed millimeter wave light, which is slightly higher in energy than radio waves, from the Submillimeter Array in Hawaii and the Atacama Large Millimeter Array in Chile. “We have never seen such a bright supernova in millimeter waves. We were shocked, “he says. So much admiration caused the phenomenon that observed the event, which since then has decreased in brightness in millimeter waves, intermittently for no less than 80 days.
In his work, Ho states that the millimeter wave data reveals that a shock wave is coming out of the explosion at one tenth of the speed of light. “The millimeter waves inform us about the early evolution of these fast-paced events and their impact on the environment,” the scientist details. By combining the millimeter wave data with the X-ray data available to the public, the team was also able to conclude that Cow is probably “driven by a motor” and that a central object was formed from a supernova, such as a black hole or a dense death.
In the future, Ho says that astronomers should be able to observe more real-time cosmic events like this at millimeter wavelengths, thanks to more modern studies such as ATLAS or the Zwicky Transient Facility (ZTF) from Caltech, which capture these events a lot. faster than before.
“You have to act fast to catch the millimeter waves, but when you do, they give you a new window to what is happening in these brilliant explosions,” he concludes.