You know what often happens in space? Explosions. A lot of explosions. Typically all these the brightest events within the visible Universe, of course – studied by astronomers. So, one of the most beautiful and vital of cosmic events is the supernova explosions that mark the deaths of massive stars and the birth of new space objects – neutron stars and black holes. But recently, researchers are faced with a new type of cosmic explosion that has something in common with supernova explosions, and explosions, generating gamma-ray bursts. But what does that mean?
The most powerful explosion in the Universe
Scientists from northwestern University (USA) have discovered a new type of cosmic phenomena related to objects or phenomena that changes its brightness and which releases large amounts of energy. The anomaly applies to FBOTs (eng. fast optical transient blue) — blue optical transients. To date, there are only three such phenomenon. To describe it in simple words, is a powerful explosion, visible in the optical, x-ray and radiologic.
How to write the astronomers in the work, published in the journal the Astrophysical Journal, the object that gave rise to the most powerful explosion in the Universe is from the Earth at a distance of 500 million light years.
In 2018, scientists have observed a bright explosion in a small galaxy located at a distance of 195,7 million light years from Earth and found that the outgoing blue light – the result of FBOTs, a new form of explosion in the Universe, the speed of expansion of which is estimated at 42 thousand kilometers per second. Unlike traditional stellar explosions, new blast AT2018COW, also called “Cow”, had an unusual brightness, which quickly rose and disappeared in just three days. According to one hypothesis, the Cow was a kind of supernova, but the exact nature of this phenomenon was not known.
Except for Cows in space was discovered two unknown explosion. The first of these, known as CSS161010 have arisen from a galaxy located about 500 million light years from Earth. Another explosion, known as ZTF18abvkwla or Koala, was discovered at a distance of about 3.4 billion light years from our planet. As a Cow, CSS161010 and Koala showed strange features – the explosion was very bright and disappeared a few days later.
Due to the strange nature of these explosions, astronomers performed follow-up observations using different telescopes and observatories. The results showed that the brightness of the Koala is similar to a gamma ray burst, the most energetic form of light in space. On the other hand, CSS161010 threw an unexpected amount of material into interstellar space at speeds exceeding half the speed of light. These unique characteristics have prompted researchers to call them quick blue optical transients (FBOTs). You may be interested in: Gamma-ray bursts could destroy extraterrestrial life
Why the new explosions are difficult to find?
It is believed that it all starts when a star more massive than the Sun, collapses under the weight of its own gravity and explodes, reaching the end of its life cycle.
The explosion sends the stellar material in its vicinity, which sometimes form a rotating disk around a supernova remnant or a black hole formed. Spinning disk, or accretion disk, can throw powerful jets of matter into interstellar space. These jets often cause powerful gamma-ray bursts.
While FBOTs was more rare and difficult than some of us hoped, in the radio they are also much more luminous than expected, which allows to obtain a fairly complete data even about as far away from our planet events.
Astronomer Daniel Perley from Liverpool John Moores University.