A research group led by graduate student Violette Impellizzeri from the Max Planck Institute for Radio Astronomy has used the 100 m Effelsberg radio telescope to detect water at the greatest distance from Earth so far. The water vapour was discovered in the quasar MG J0414+0534 at redshift 2.64, which corresponds to a light travel time of 11.1 billion years, a time when the Universe was only a fifth of the age it is today.
The water vapour is thought to exist in clouds of dust and gas that feed the supermassive black hole at the centre of the distant quasar. The detection was later confirmed by high-resolution interferometric observations with the Expanded Very Large Array.
The discovery of water in the early Universe was possible only due to the chance alignment of a foreground galaxy and the distant quasar MG J0414+0534. The foreground galaxy acts like a cosmic telescope, magnifying and distorting the light from the quasar forming four distinct images of the quasar. Without this gravitational lensing effect, 580 days of continuous observations with the 100 m telescope would have been needed instead of the 14 hours used to make this remarkable discovery. “Others have tried and failed to find water, and we knew we were looking for a very faint signal”, says Violette Impellizzeri, “so we thought of using a foreground galaxy like a cosmic magnifying glass to observe at a far greater distance and had to be persistent, and sure enough the line emission of water popped up.” … – sd