Image: NRAO / AUI / NSF
Astronomers at northwestern University in the US have discovered a new type of cosmic phenomena related to the transients, that is, to change the brightness of the objects or phenomena in which there is a release of large amounts of energy. The anomaly refers to the FBOT (eng. fast optical transient blue) — blue optical transients, and scientists know of only three such phenomenon. In fact, it is a heavy duty explosion, visible in the optical, x-ray and radiologic. Article with results of observations published in The Astrophysical Journal.
The object that originated the explosion, is 500 million light-years from Earth. The characteristics of it is reminiscent of another famous FBOT — AT2018COW, also called “Cow”. AT2018COW found June 17, 2018 at a distance of 195,7 million light years, when an unknown object suddenly increased its luminosity to the level of the brightest supernova, and he did it for a record three days. None of the known at that time, the type of transients could not produce such a quick flash, the speed of expansion of which is estimated at 42 thousand kilometers per second. According to one hypothesis, the “Cow” was a very kind of supernova, but the exact nature of the phenomenon remained unclear.
However, the new FBOT designated as CSS161010, was stronger and faster, “Cow.” It gave rise to the outflow of gas and particles, the speed of which reached 55 percent of the speed of light. It is known that such are able to do gamma-ray bursts, but they run the material whose mass is only a millionth the mass of the Sun. Scientists estimate that CSS161010 dispersed to more than half the speed of light from 1 to 10 percent of the mass of the Sun. Based on this, researchers believe that the FBOT is the fastest transition process in the Universe.
Before the discovery CSS161010 the main mechanism FBOT was considered the collapse of a massive star gamma-ray burst or the merger of neutron stars. However, scientists believe that a rare transient was generated by the absorption of stars by the black hole. Another key to the nature of the phenomenon are places where there is FBOT. This is a small galaxy that contains about 10 million stars (for comparison: the milky Way contains billions of stars), are characterized by low metallicity, that is, they have few elements heavier than hydrogen and helium. Giant star of low metallicity for all his life saves a lot, then dies in heavy duty flash. This explains why FBOT are not observed in larger galaxies.
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