'Megamaser' is most distant sign of cosmic water
A foreground galaxy distorts the quasar MG J0414+0534 into four images; two reveal water maser emission. Seen from nearby, the quasar might look similar to the galaxy M87 (inset at lower right) (Illustration: Milde Science Communication/HST Archive data/CFHT/J-C Cuillandre/Coelum)
Water has been spotted inside a galaxy at the edge of the visible cosmos. Finding other such signals could help pin down the properties of monster black holes in the early universe.
The telltale sign of the water is maser emission - the microwave equivalent of laser light - coming from warm water vapour inside a distant quasar, an energetic galaxy powered by gas and dust swirling onto a giant black hole.
The quasar, called MG J0414+0534, is so distant that its light has travelled for 11.1 billion years to reach the Earth, having left when the universe was only 2.5 billion years old. It beats the previous distance record for a watery galaxy by many billions of light years.
"We now know water is out there," says Violette Impellizzeri from the Max Planck Institute (MPI) for Radio Astronomy in Bonn, Germany. "Because water masers arise close to the cores of galaxies, our result opens new interesting possibilities for studying supermassive black holes at a time when galaxies were forming."
Impellizzeri's team used the 100-metre Effelsberg radio telescope to observe the quasar, which is particularly bright thanks to an effect called gravitational lensing. The gravity of a foreground galaxy acts like a cosmic telescope, magnifying the quasar's light and distorting it into four separate images.