Astronomers find most distant signs of water in the Universe to date
Washington, April 23: Astronomers have found the most distant signs of water in the Universe to date, in the form of water vapor contained in a jet ejected from a supermassive black hole at the center of a galaxy.
Dr. John McKean of the Netherlands Institute has made the discovery for Radio Astronomy (ASTRON).
The water emission is seen as a maser, where molecules in the gas amplify and emit beams of microwave radiation in much the same way as a laser emits beams of light.
The faint signal is only detectable by using a technique called gravitational lensing, where the gravity of a massive galaxy in the foreground acts as a cosmic telescope, bending and magnifying light from the distant galaxy to make a clover-leaf pattern of four images of MG J0414+0534, the galaxy in question.
The water maser was only detectable in the brightest two of these images.
According to Dr. McKean, “We have been observing the water maser every month since the detection and seen a steady signal with no apparent change in the velocity of the water vapor in the data we’ve obtained so far.”
“This backs up our prediction that the water is found in the jet from the supermassive black hole, rather than the rotating disc of gas that surrounds it,” he said.
The radiation from the water maser was emitted when the Universe was only about 2.5 billion years old, a fifth of its current age.
“The radiation that we detected has taken 11.1 billion years to reach the Earth. However, because the Universe has expanded like an inflating balloon in that time, stretching out the distances between points, the galaxy in which the water was detected is about 19.8 billion light years away,” explained Dr. McKean.
The team is now analyzing high-resolution data to find out how close the water maser lies to the supermassive black hole, which will give them new insights into the structure at the center of active galaxies in the early Universe.
“This detection of water in the early Universe may mean that there is a higher abundance of dust and gas around the super-massive black hole at these epochs, or it may be because the black holes are more active, leading to the emission of more powerful jets that can stimulate the emission of water masers,” said Dr. McKean. (ANI)