Chandra finds new evidence of a hot intergalactic environment

Chandra finds new evidence of a hot intergalactic environment

After many years of research, Chandra's X-rays of Abell 98 finally seem to indicate the existence of WHIM, a warm intergalactic environment, between galaxies and clusters of galaxies.

For many years, astronomers have used NASA's X-ray Space Observatory "Chandra" to find evidence of "missing" mass between galaxies. This material, called Warm-Hot Intergalactic Medium, WHIM, will be a material in the form of giant overheating threads in an intergalactic environment. Unfortunately, few studies have been successful. A recent study by Chandra of colliding galaxies in Abell 98 has finally provided new clues for the existence of WHIM.

The newly restored image presented at the beginning of the article shows Abel 98

What is a hot intergalactic environment?

This missing material is not dark matter. Dark matter is invisible, unknown in nature, and is considered to be the majority of matter in the universe. Instead, WHIM will be a common matter, which is contained in conventional objects such as stars and planets. About a third of this matter, created in the first billion years after the Big Bang, has not yet been detected in local observations.

Researchers suggested that at least part of this mass could be hidden in giant threads of warm or hot gas between galaxies and clusters of galaxies. They called it WHIM.

Direct evidence in new data

A team of astronomers examined Chandra's Abell 98 data, a galaxy accumulation system located about 1.4 billion light years away from Earth, showing an X-ray bridge between two colliding clusters containing:

  • The gas at a temperature of about 20 million Kelvins is probably one of two clusters that overlaps each other.

The observations are consistent with the theoretical predictions of the WHIM characteristics.

The X-ray data from Changra also showed a shock wave, and the position determined by the sudden decrease in X-ray luminance and gas temperature was measured from the north to the south.

This is the first time that astronomers have discovered such a shock wave in the early stages of a galaxy collision before the galaxy centres meet and lean on each other. This shock wave can be directly related to the discovery of WHIM in Abell 98 because it heated the gas between clusters of galaxies when they crash.

An article discussing these results, published in The Astrophic Journal Letters, is available.

Further evidence of the existence of the WHIM thread between these two clusters was found by the Suzaku X-ray telescope of the Japan Aerospace Exploration Agency in a new study. A parallel study also provides evidence of the existence of WHIM on the opposite side of the cluster, which leads to the collision identified in the image above. These two WHIM detections indicate that the clusters are located along a huge structure 13 million light years long.

An article on this other study was accepted for publication in The Astrophic Journal and is available as a preprint version.