Once again, astronomers have spotted a rare and mysterious blue flash. This discovery increases the mystery surrounding this type of cosmic explosion.
An extremely bright explosion in the universe, which was already very rare and strange, has become even more mysterious. Astronomers again saw a “blue flash” (Luminous fast blue optical transients, or LFBOTs) were monitored. But what makes this discovery remarkable is that this phenomenon was not in the place normally expected, inside the star-forming region, but surprisingly outside it.
More about LFBOTs
Fast Luminous Blue Optical Transients (LFBOTs) are some of the brightest events known in the Universe. They appear suddenly, like camera flashes. These intense, rapid blue flashes are only visible for a few days, a very short period compared to supernovae, which can continue to shine for weeks or even months. The first LFBOT was spotted in 2018 and was named AT2018cow (or cow). The powerful explosion initially looked like a supernova, although it was much faster and brighter than any other star explosion scientists have discovered so far. The object was 10 to 100 times brighter than the average supernova. Since the discovery of the first LFBOT, only a few of these strange phenomena have been documented. Each of these events has been given a nickname based on the last letters of its astrological designation, which indicate the name of the animal. Currently, LFBOTs are discovered approximately once a year.
It is currently unclear what causes blue flashes. The latest blue flash, which has been dubbed “The Sparrow,” raises more questions.
Because flashes appear quickly and disappear quickly, astronomers search for them with telescopes that continuously monitor large areas of the sky. The bird was tracked down with assistance Zwicky Transit FacilityIt is a telescope that maps the entire northern sky every two days. After the bird was first discovered, the event was observed by several telescopes covering different parts of the electromagnetic spectrum, from X-rays to radio waves. But ultimately, it was the Hubble Telescope’s extremely high resolution that allowed scientists to pinpoint the exact location of the newly discovered LFBOT.
Chaffinch showed all the hallmarks of LFBOT, such as intense emission of blue light and rapid evolution, quickly reaching maximum brightness and then fading within a few days. Spectroscopic measurements performed with Gemini southThe telescope in Chile revealed that the bird’s temperature was very high, reaching 20,000 degrees Celsius. But unlike other LFBOTs seen before, Chaffinch happened in a completely unexpected place, far away from any star system. This is strange. So far, all previous LFBOTs have been discovered in the spiral arms of galaxies where new stars were forming at the time.
But Hubble discovered that Finch is located exactly between two neighboring galaxies. It is located about 50,000 light-years from a nearby spiral galaxy and about 15,000 light-years from a smaller galaxy. This is a somewhat confusing site, because, as mentioned earlier, these cosmic events are generally thought to occur within galaxies. “The observations made with the Hubble Telescope are invaluable,” says study leader Ashley Kremes. “They made us realize that this situation is exceptional compared to other similar cases. Without Hubble data, we would have had no idea about these unusual properties.
To understand the sparrow’s strange location, scientists are examining two possible explanations. The first is that it was the explosion of a star that was moving very quickly. Another hypothesis is that they were formed as a result of the collision of two neutron stars that approached each other over billions of years and eventually collided. “This discovery raises many more questions than it answers,” Krems said. “More research is needed to find out which of the possible explanations is correct.”
Hubble results It suggests that astronomers actually understand less about LFBOTs than they initially thought. “The more we find out about LFBOTs, the more they surprise us,” the researcher points out. “We have now shown that LFBOTs can occur at large distances from the center of the nearest galaxy, and this is in stark contrast to what we normally expect from supernovae.” In the coming years, astronomers hope to discover more of these blue flashes to better understand this phenomenon. They pinned their hopes, among other things, on the project currently under construction Vera C. Rubin Observatory In Chile. This telescope will scan the entire southern sky every few nights, which will allow researchers to spot more mysterious LFBOTs.
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