ESA XMM Newton and NASA Chandra: Large chunk of missing universe found

Large chunk of missing universe found COSMOS magazine


Scientists using two X-ray telescopes have found evidence for the 'missing matter' in the nearby universe.

This matter is made up of hot diffuse gas, which is known as WHIM (warm-hot intergalactic medium).

To get this result, researchers analyzed X-ray light from a distant quasar that passed through a 'wall' of galaxies about 400 million light-years away.

A large chunk of missing matter - theorised but never before measured - has been discovered as a vast smear of extremely hot intergalactic gas 400 million light-years away.


For the predominant theories about the formation and evolution of the universe to hold true, a certain amount of matter should be present; but large amounts of it have long remained elusive.

Now an international team of astronomers have found most of the missing matter, pinpointing its location using two different X-ray telescopes.

Clues to how galaxies formed
"We didn't just find a 'lost & found' item in the cosmic baryon budget," said Taotao Fang of the University of California at Irvine and lead author of the paper in The Astrophysical Journal, "our findings provide important clues to the question of how galaxies formed and evolved.

"The missing matter we found are the leftovers from the early galaxy formation process," said Fang.

The missing matter has long been hypothesised, and some of it has even been spotted before; but previous observations did not uncover the full extent of this massive gas cloud.
Higher temperatures
"What [previous studies] found is the missing matter at lower temperatures ... about 10-20% of the total missing matter," said Fang. "What we found are missing matter at higher temperatures and account for the majority 80 to 90% of the missing matter."
By using two X-ray telescopes, instead of one visible light telescope as in previous studies, the exact location of the missing matter could be calculated and the results were more robust.
The X-ray telescopes that captured the images identifying the location of the missing matter are housed on NASA's Chandra and the European Space Agency's XMM-Newton - which has a command centre in Perth, Australia. Both orbital observatories that have been in space since 1999.