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Artist’s depiction of a gamma ray burst.
According to a recent study, the Arizona-based Very Energetic Radiation Imaging Telescope Array System also known as VERITAS detected a flare of telltale gamma rays from a remote galaxy, which scientists believe that it is located halfway across the visible universe.
The discovery helped astronomers learn more about how these gamma rays emerge and their exact birth location. The source of the gamma-rays was located within an extremely active galaxy dubbed PKS 1441+25. But the gamma ray flare was not ejected by the galaxy’s supermassive black hole at its center. Instead the source of radiation was some 5 light-years away, researchers estimated.
The galaxy is of a very rare type also known as a blazar. Blazars are very bright and active galaxies with a monster black hole at their cores. Because of their restlessness, blazars can release flares that can be tens of times brighter than the entire galaxy’s base radiation. A similar flare was detected earlier this year by various telescopes across the globe including VERITAS (which in Latin means ‘Truth’).
Jonathan Biteau of the UC Santa Cruz, who studied the radiation, explained that the flare had the highest level of energy ever detected by our telescopes. He added that the tremendous amount of radiation took everyone by surprise because theoretically the radiation should be blocked by the obstacles encountered in its incredibly long journey.
Researchers said that gamma rays are usually annihilated by photons in the process. This is why the team was surprised to learn that the radiation made it to Earth’s telescopes and somehow escaped the dense net of photons around their galaxy’s black hole and the less dense nets of photons on their way here.
According to scientists, the universe is filled with the extragalactic background light (EBL) that severely disrupts high-level radiation trying to reach us. EBL is made of photons coming from defunct galaxies and stars. Scientists were never able to measure the EBL because of disrupting sources of light in the universe.
The team explained that the farther a galaxy is, the higher the chances of its radiation to be eliminated by the EBL are. This is why the recent findings can now help scientists better understand and measure the EBL.
Study authors noted that the fact that the gamma ray flare was not caught into the dense net of photons around the supermassive black hole suggests that its source is located farther away from the galaxy’s core.
A paper on the findings was published Dec 15 in the Astrophysical Journal Letters.
Image Source: Wikimedia
